Phan II. Cac Vi Khuan Gay Benh

7/31/2019 Phan II. Cac Vi Khuan Gay Benh

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PHN II

CC VI KHUN GY BNH THNG GP

CC CU KHUN GY BNH

Mc tiu hc tp1. Trnh by c mt s tnh cht vi khun hc ca mt s cu khun gy bnh.2. Nu c kh nng gy bnh ca cc cu khun ny.3. Trnh by c mt s phng php chn on vi khun hc i vi cc cu khun gybnh.

Cu khun gy bnh bao gm T cu, Lin cu, Ph cu vNeisseria. l nhng vikhun hnh cu v c gi chung l cu khun sinh m. TrNeisseria, cc cu khun sinhm u Gram dng.

I. T CU (STAPHYLOCOCCI)T cu tm thy khp ni v c th phn lp t khng kh, bi, thc phm, c th

ngi v ng vt. T cu l thnh vin ca khun ch da hoc nim mc t hu ngi. C 3loi t cu c kh nng gy bnh nhim trng ngi: Staphylococcus aureus (S.aureus: tcu vng) c xem l t cu gy bnh, Staphylococcus epidermidis (S. epidermidis) vStaphylococcus saprophyticus (S. saprophyticus) thng xem nh l t cu khng gy bnh;tuy nhin 2 loi sau cng c th gy nhim khun ng tit niu hoc nhim khun trong

phu thut tim, trong thng tnh mch. Ni dung bi ny tp trung vo S. aureus.1.c im sinh vt hc1.1. Hnh thi

Vi khun hnh cu hoc hnh thun, ng knh 0,8-1m, canh thang thng hpthnh tng cm nh chm nho, hnh thc tp hp ny do vi khun phn bo theo nhiu chiutrong khng gian. Trong bnh phm vi khun hp tng i hoc m nh. Vi khun bt muGram (Gram dng). Vi khun khng di ng, khng sinh nha bo, thng khng c v.1.2. Tnh cht nui cy

Vi khun pht trin d dng mi trng thng thng, hiu kh hoc k kh ty ,mc tt 370C nhng to sc t tt 200C. canh thang sau 5 - 6 gi lm c mitrng, sau 24 gi lm c r. mi trng c, khun lc trn li, bng lng, ng nhc th c mu vng m, mu vng cam hoc mu trng, tng i ln sau 24 gi.

Nhng chng khc nhau lm tan mu nhng mc khc nhau, thch mu typ tanmu thng c quan st xung quanh khun lc.

1.3. Tnh cht sinh ha v khngT cu c h thng enzyme phong ph, nhng enzyme c dng trong chnon l: catalase (phn bit vi lin cu), S. aureus c coagulase (tiu chun quan trng phn bit t cu vng vi cc t cu khc). T cu ln men chm nhiu loi ng,to axt nhng khng sinh hi, S. aureus ln men ng mannt. T cu tng i chunhit v thuc st khun hn nhng vi khun khc, chu kh v c th sng mitrng nng NaCl cao (9%), nhy cm thay i vi khng sinh, nhiu chng khngvi penicillin v cc khng sinh khc.1.4. Cu trc khng nguyn

Vch t bo vi khun cha khng nguyn polysaccharid, khng nguyn protein A b mt. Ngi ta c th cn c vo cc khng nguyn trn chia t cu thnh nhm,

tuy nhin phn ng huyt thanh khng c gi tr trong chn on vi khun.

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Cn c vo s nhy cm vi phag, ngi ta chia t cu thnh typ phag. Nhng bphage cho php xp loi phn ln cc chng t cu thnh 4 nhm phag chnh. nh typphage t cu c gi tr v dch t hc v chn on.1.5. Cc c t v enzyme

Kh nng gy bnh ca t cu l do vi khun pht trin v lan trn rng ri trong

m cng nh to thnh nhiu c t v enzyme.1.5.1. Hemolysin:c4 loi hemolysin c xc nh l , , v . Mt chng t cuc th to thnh nhiu hn mt loi hemolysin. l nhng phm vt bn cht proteingy tan mu nhng tc ng khc nhau trn nhng hng cu khc nhau. Chng c tnhsinh khng. Mt vi loi hemolysin gy hoi t da ti ch v git cht sc vt thnghim.1.5.2. Leucocidin: l nhn t git cht bch cu ca nhiu loi ng vt, bn cht

protein, khng chu nhit. T cu gy bnh c th b thc bo nh t cu khng gy bnhnhng li c kh nng pht trin bn trong bch cu.1.5.3. Coagulase: lm ng huyt tng ngi hoc th chng ng vi citrat natri hocoxalat natri. Coagulase lm dnh t huyt vo b mt vi khun v do hnh nh cn tr

s thc bo. Tt c cc chng S. aureus u c coagulase dng tnh.1.5.4. Hyaluronidase: thy phn axit hyaluronic ca m lin kt, gip vi khun lan trnvo m.1.5.5. -lactamase: s khng penicillin ca t cu vng l do a s t cu vng snxut c enzyme -lactamase.

Ngoi ra, t cu cn c nhng enzyme khc nh staphylokinase l mtfibrinolysin lm tan t huyt, nuclease, lipase.1.5.6. c t rut: do mt s chng t cu to thnh, c bit lc pht trin nng CO2 cao (30%) v mi trng c va. N khng s un si trong 30 pht cng nhtc ng ca enzyme rut. C 5 typ huyt thanh A, B, C, D, E; typ A, B thng gy

ng c thc n.1.5.7. c t gy hi chng shock nhim trng (Toxic schock syndrome toxin: TSST):thng gp nhng ph n c kinh nguyt dng bng bng dy, bn hoc nhng ngi

b nhim trng vt thng. C ch gy shock ca n tng t vi ni c t.1.5.8. Exfoliatin toxin hay epidermolitic toxin: l mt ngoi c t, gy nn hi chng

phng rp v chc l da (Scaded skin syndrome) tr em. 85% cc chng t cu vngthuc loi phage nhm II to c t ny. N gm 2 loi A v B, u l polypeptid, loiA bn vng vi nhit 1000C/20pht, cn loi B th khng. C th xc nh chng

bng k thut min dch (nh ELISA hoc RIA hay min dch khuch tn). Khng thc hiu c tc dng trung ho c t ny.1.5.9. Alpha toxin: bn cht protein, gy tan cc bch cu a nhn v tiu cu, t gy

ra p xe, hoi t da v tan mu. c t c tnh khng nguyn nhng khng th ca nkhng c tc dng chng nhim khun.2. Kh nng gy bnh

ng xm nhp l da (gc chn lng, ch b thng) v nim mc. T cukhng gy nn mt chng bnh nht nh nhng thng lm pht sinh nhiu hnh thcnhim khun khc nhau. T cu thng gy nn nhng im nung m da, nim mcnhng c th xm nhp vo nhng c quan khc nhau. S nhim trng xy ra nhngc th khng st km nh gi yu, tr cn b, bnh i tho ng.2.1. Cc nhim trng da v nung m su

L mt hnh thc c bit, nng l inh ru, tip n l chc l, vim ty xng,vim phi mng phi, vim mng ngoi tim, vim mng no.

2.2. Nhim trng huyt

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T nhng im nung m, vi khun c th i vo mu v gy nn nhim trnghuyt. Nhim trng huyt do t cu l mt bnh thng gp bnh vin, thng xy ra ngi c sc khng gim st.2.3. Vim rut cp tnh

Thng gp cc bnh nhn ung khng sinh c khng khun ph rng, khng

sinh hy dit nhng vi khun bnh thng rut, lm pht trin chng t cu sinh c trut v gy nn chng bnh.2.4. Ng c thc n

Do t cu sinh c t rut c bit typ huyt thanh A v B gy nn. Chng bnhc nhng c im: thi gian bnh ngn (1-8 gi), bun nn d di, nn, au bng, achy, khng st, bnh phc trong vng 24 gi.2.5. Hi chng da phng rp (Scalded skin syndrom)

Mt s chng t cu vng tit c t exfoliatin, gy vim da hoi t v phngrp. Bnh ny thng gp tr mi v tin lng xu.2.6. Hi chng shock nhim c (Toxic shock syndrome)

Thng gp nhng ph n c kinh nguyt dng bng v sinh dy, bn, b nhim

vi khun t cu vng. Bnh khu tr m o v cn nguyn l t cu vng, lin quann c t gy hi chng shock nhim trng, cy mu khng tm thy t cu vng.3. Chn on vi khun

Bnh phm l m, mu, m gii, phn, nc no ty ty theo chng bnh. Phnlp thch mu, canh thang hoc thch Chapman. Xc nh nh hnh thi knh hin viv tnh cht sinh ha. T cu c xem nh S. aureus nh 4 tiu chun : sc t vng, tanmu, ln men ng mannit, to thnh coagulase. Trong 2 tiu chun coagulase vln men ng mannit l quan trng nht, ch c th thiu mt trong 2 tiu chun chkhng th thiu c 2.

Phn ng huyt thanh khng c gi tr chn on vi khun.Ngi ta nh typ t cu bng phag. Nh nhng phag chnh c hiu ngi ta xp

t cu vo mt trong 4 nhm phag chnh (I, II, III v IV). T cu thuc nhm no th bly gii bi mt hoc nhiu phag trong nhm . nh typ phag c gi tr v dch t hc.4. Phng nga v iu tr4.1. Phng nga

Ngun t cu trong thin nhin l ngi. S ly nhim t ngi ny sang ngikhc l do tip xc trc tip hoc qua khng kh. Nhng ngi lnh mang trng ckhuyn co khng nn lm vic phng sinh, phng tr s sinh, phng m hoc cc xnghip thc phm.4.2. iu tr

Nhiu chng T cu khng vi nhiu khng sinh nht l penicillin nn cn lm

khng sinh . C trng hp s dng vaccine bn thn v vaccine tr liu c kt qu.II. LIN CU (STREPTOCOCCI)Lin cu l nhng cu khun xp thnh hnh chui, phn b rng ri trong thin

nhin. Mt vi loi l thnh vin ca khun ch bnh thng ngi. Mt vi loi gynn nhng chng bnh quan trng.1. c im sinh vt hc

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1.1. Hnh thVi khun hnh cu, ng knh1 m, Gram dng, thng xp thnh chui di

ngn khc nhau, c th ng i hoc ring l. Vi khun khng c lng, khng to nhabo. Nhiu chng thuc nhm A v C to v axit hyaluronic.1.2. Tnh cht nui cy

Lin cu l nhng vi khun hiu k kh ty , ch pht trin tt mi trng cmu hoc c cc dch ca c th khc. Nhng chng gy bnh thng i hi nhiu yut pht trin. Phn ln lin cu tan mu gy bnh pht trin tt 370C. Cc lin cu rut

pht trin tt khong nhit t 10 n 450C. mi trng lng vi khun d to thnhcc chui, sau 24 gi canh thang vn trong v c nhng ht, nhng cm dnh vo thnhng sau lng xung y ng.

thch mu, khun lc nh trn li mu hi xm, bng hoc m c. Nhngchng ca lin cu A c v to nn nhng khun lc ly nhy. Lin cu gy nn 3 typtan mu: tan mu ca lin cu tan mu A, tan mu ca lin cu viridans v tan mu ca lin cu khng tan mu.1.3. Tnh cht sinh vt ha hc

Lin cu khng c catalase (khc vi t cu). Lin cu A c bit nhy cm vibacitracin. phn bit lin cu v ph cu, ngi ta da vo kh nng ca lin cu khng vi mt hoc mui mt hoc vi optochin trong khi ph cu th ngc li.1.4. Cu trc khng nguyn

Lin cu c cu trc khng nguyn phc tp.1.4.1. Khng nguyn v axit hyaluronic

Tm thy v mt s lin cu A, khng c tnh cht sinh khng.1.4.2. Khng nguyn carbohydrat C c hiu nhm

y l khng nguyn nm vch t bo vi khun. Da vo khng nguyncarbohydrat C, Lancefield chia lin cu tan mu thnh nhiu nhm huyt thanh t A nO. Phn ln nhng lin cu gy bnh ngi thuc nhm A, tuy nhin nhng chngnhm B, C v G cng tm thy trong nhim trng h hp, nhim trng huyt v vimmng trong tim.1.4.3. Khng nguyn M c hiu typ

Khng nguyn M cng nm vch t bo vi khun, l protein M lin h nLin cu A v tm thy nhng vi khun to thnh khun lc m c hoc ly nhy. Ncn tr s thc bo. Cn c vo khng nguyn ny ngi ta chia lin cu A thnh nhiutyp, hin c trn 55 typ trong typ 12 gy bnh rt nghim trng.1.4.4. Phm vt T

Bn cht protein, khng lin quan n c lc, thu c bng cch thy phn ph hy protein M. Phm vt T cho php phn bit mt s typ lin cu.

1.5. Cc enzyme v c tLin cu to thnh nhiu enzyme v c t.1.5.1. Streptokinase

Tm thy nhiu chng lin cu tan mu . N bin i plasminogen thnhplasmin c kh nng thy phn t huyt v nhng protein khc. Streptokinase kch ngs to thnh khng th khng streptokinase (ASK) v enzyme ny c s dng iutr nhng tr ngi do ng mu gy nn.1.5.2. Streptodornase

Enzyme ny c kh nng thy phn DNA do lm lng m. Mt ch phm chastreptokinase v streptodornase c dng lm lng dch ngoi tit c, gip chokhng sinh n ch nhim trng v c s dung trong lam sng iu tr vim m

mng phi.1.5.3. Hyaluronidase :

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Thy phn axit hyaluronic, cht cn bn ca m lin kt v gip cho vi khunbnh trng su rng vo cc m.1.5.4. Dung huyt t :

Lin cu tan mu to thnh 2 loi dung huyt t :- Streptolysin O: c hot tnh tan mu trng thi kh oxy, nhng nhanh chng

b bt hot trng thi oxy ha. C tnh cht sinh khng mnh, n kch ng to thnhkhng th khng streptolysin O (ASO). Trong chn on bnh thp khp cp v vimcu thn cp, vic nh hiu gi ASO rt c gi tr khng nh nhim lin cu.

- Streptolysin S: chu trch nhim v s hnh thnh vng tan mu xung quanhkhun lc thch mu, khng b bt hot bi oxy v khng c tnh sinh khng.1.5.5. c t sinh :

Gy pht ban trong bnh tinh hng nhit, thng tm thy lin cu A.2. Phn loi lin cu

Da vo kh nng lm tan mu, s khng vi tc nhn l ha v th nghimsinh ha ngi ta chia lin cu thnh 4 nhm :2.1. Lin cu tan mu

To dung huyt t ha tan chu trch nhim v typ tan mu thch mu. Chngto thnh cacbohydrat C c hiu nhm. Da vo cacbohydrat C ngi ta chia lin cutan mu thnh nhiu nhm t A n O.2.2. Lin cu viridans

Khng gy tan mu thch mu. Nhiu loi gy tan mu , nhng cng cnhng loi khng tc dng vi mu. Lin cu viridans khng to thnh cacbohydrat C.Chng l thnh phn ch yu ca khun ch ng h hp v ch gy bnh lc xmnhim van tim khng bnh thng hoc mng no hoc ng tiu.2.3. Lin cu rut

To thnh cacbohydrat C c hiu nhm D, pht trin tt nhit t 10-

45

o

C, nng 6,5% NaCl v thch 40% mui mt. Kh nng tan mu thay i.Chng c tm thy khun ch bnh thng rut v c th gy bnh lc xm nhimm, mu, ng tiu hoc mng no.2.4. Lin cu lactic

Tan mu thay i, pht trin thch cha 40% mt nhng khng pht trin 45oC, khng gy bnh, thng tm thy trong sa.3. Kh nng gy bnh

Trong cc lin cu th lin cu nhm A l nhm lin cu gy bnh nhiu nht ngi. Chng gy nn nhng bnh cnh sau :3.1. Cc nhim khun ti ch

Nh vim hng, vim t hu, chc l, vim qung ngi ln, nhim khun cc

vt thng.3.2. Cc nhim khun th phtNh vim mng trong tim cp, st hu sn hoc nhim khun huyt m im xut

pht l t da, t cung hoc t vng t hu.3.3. Bnh tinh hng nhit

Thng gp tr em trn 2 tui cc nc n i.3.4. Cc di chng ca nhim lin cu A

c im ca nhim khun Lin cu A l s xut hin cc di chng 2-3 tun lsau bnh lin cu, c bit l sau vim hng. Di chng c th l vim cu thn cp hocthp khp cp.3.4.1. Vim cu thn cp

Xy ra mt s ngi 1-3 tun l sau khi nhim lin cu A, c bit l nhimcc typ 12, 4, 49 hoc 57 hng hoc da, do s tc ng ca phc hp khng nguyn-

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khng th ln mng c bn ca tiu cu thn. Triu chng l tiu mu, ph thng, caohuyt p. Cc gi thuyt cho rng l do s tc ng ca khng th chng li khngnguyn vch ca lin cu nhm A phn ng cho vi mng y ca cu thn.3.4.2. Thp khp cp

L mt di chng nghim trng nht v n a n ph hy c tim v van tim. Mt

vi chng lin cu A c khng nguyn mng t bo phn ng cho vi si c tim. Huytthanh ca bnh nhn thp khp cp cha khng th phn ng vi nhng khng nguyn. Thp khp cp c xu hng tr nn nghim trng trong nhim trng ti pht.

Ngoi ra, phc hp min dch globulin min dch-b th-khng nguyn ca lincu c chng minh bng min dch hunh quang thng tn ca tiu cu thn vc tim.4. Tnh min dch

S khng vi lin cu c tnh cht c hiu typ. Ch c khng th khng M chiu typ c kh nng chng li s nhim trng. Lin cu A c trn 55 typ huyt thanh. Nhnchung khng ngi no tr nn min dch vi tt c nhm lin cu A. Cc khng th khngStreptolysin O v khng Streptokinase khng c kh nng bo v c th.

5. Chn on vi sinh vt5.1. Chn on trc tip

Bnh phm thch hp, c th l mu, m, m gii, nc tiu, nc no ty v..v..rinui cy ln trn cc mi trng thch hp; phn lp v nh danh vi khun da vo c imhnh th, tnh cht nui cy, tnh cht khun lc, tnh cht tan mu. Nhng chng lin cu Art nhy cm vi bacitracin. Xc nh nhm ca lin cu tan mu nht l nhm A, B, C, G

bng th nghim ng ngng kt.5.2. Chn on gin tip

Trong cc trng hp nh thp khp cp c th s dng phn ng ASO nh hiugi ASO trong mu bnh nhn. y l mt phn ng trung ha enzyme, bnh thng hiu giASO < 200 n v. Trong trng hp bnh l ASO tng cao. ASK t c s dng.6. Phng bnh v iu tr6.1. Phng bnh

Ngun nhim lin cu A l ngi, ch yu l phng bnh chung nh pht hin smnhng nhim trng da, hng do lin cu A gy nn iu tr vi khng sinh thch hp.Cn pht hin v iu tr nhng ngi lnh mang trng phc v cc nh h sinh, nh tr,

phng m.6.2. iu tr

i vi lin cu A phi iu tr sm liu lng y vi khng sinh git khun nhpenicillin, erythromycin.

i vi lin cu viridans, lin cu rut, cn phi hp khng sinh gia nhm lactamin

v aminoglycosit nh penicillin v streptomycin hoc iu tr theo khng sinh .III. PH CU (STREPTOCOCCUS PNEUMONIAE)Ph cu thng gp vng t hu ca ngi bnh thng vi t l kh cao (20-40%).

1. c im sinh vt hc1.1. Hnh th

Ph cu l cu khun Gram dng, hnh ngn nn, xp thnh i, 2 u ging nhaunhn vo nhau to thnh hnh mt knh hay s 8. Trong mi trng nui cy, ph cu thngxp thnh chui ngn d nhm vi lin cu. Trong bnh phm hay trong mi trng nui cygiu albumin th vi khun to v. Nui cy lu ngy mi trng nhn to th khng c v.Vi khun khng c lng, khng to nha bo. Nhng enzyme t ly gii lm cho vi khun mtmu Gram ri ly gii.

1.2. Tnh cht nui cy

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Ph cu l vi khun hiu k kh ty , mc tt mi trng giu cht dinh dng v kh trng 5 - 10% CO2. Nhit thch hp 370C, pH 7,2 - 7,6. thch mu khun lc sau 24gi nh, trn, b u, trong, lc u li, sau lm gia vi b cao xung quanh, to vngtan mu xung quanh khun lc.1.3. Tnh cht sinh ha

Ph cu ln men nhiu loi ng, khng sinh hi, catalase m tnh, phn ngNeufeld dng tnh (tan trong dung dch mt hay mui mt), khng mc mi trng coptochin.1.4. Sc khng

Ph cu d b git cht bi nhng cht st khun thng thng (Phenol, Cl 2Hg) vnhit (60 0C trong 30 pht). Trong qu trnh gi chng, vi khun d b gim c lc hoc bini t dng khun lc S sang dng R (khng c v). Ph cu khng chu c nhit qulnh v qua nng. Nhit gi chng thch hp l 18 oC - 30oC.1.5. Cu trc khng nguyn1.5.1. Khng nguyn v: bn cht polysaccharide. Da vo khng nguyn v, ph cu cchia thnh 85 typ huyt thanh. V gi vai tr quan trng trong c lc ca vi khun.

1.5.2. Khng nguyn thn: bao gm carbohydrat C c hiu nhm v protein M c hiu typtng t nh lin cu A.2. Kh nng gy bnh

Ph cu thng gp t hu vi t l kh cao. Lc ng h hp b thng tn, phcu xm nhp vo c th gy bnh ng h hp, in hnh l vim thy phi, thng do typ1, 2, 3 gy nn. Bnh xy ra l t, c th tr thnh dch c bit v ma ng. N cng thnggy vim ph qun, p xe phi, vim mng phi c m.

Ph cu cn l mt tc nhn thng gy vim mng no m tr em.Ngoi ra ph cu cn gy cc nhim khun khc nh vim xoang, vim tai, vim

hng, vim kt mc mt, vim mng ngoi tim, vim khp, nhim khun huyt.3. Chn on vi sinh vt

Nhum Gram, nu thy nhiu cu khun Gram dng hnh ngn nn xp tng ing thi vi bch cu a nhn v i thc bo s b chn on vim do ph cu v c th btu iu tr. ng thi nui cy chn on xc nh. nh danh vi khun da vo cim hnh th, khun lc v mt s th nghim phn bit vi lin cu tan mu nh neufelddng tnh, optochin dng tnh.

nh typ ph cu bng phn ng phnh v.4. Phng bnh v iu tr4.1. Phng bnh

Hin nay vaccine polysaccharide v cha ph bin. Ch yu l phng bnh chung: lcsc khng ca c th gim nh b cm cn bi dng sc khe, tr em ngi gi yu d b

ph vim cn mc m v ma ng, lc c s thay i t ngt nhit .4.2. iu trCn iu tr sm. Ph cu nhy cm vi erythromycin, penicillin, ampicillin,

chloramphenicol, bactrim.IV. NO M CU (NEISSERIA MENINGITIDIS)1. c im sinh vt hc1.1. Hnh th

Cu khun Gram m hnh ht c ph 0,8 x 0,6 m, thng ng thnh i ring lhoc thnh m nh. Xem trc tip t bnh phm c th tm thy vi khun trong bch cua nhn. Vi khun khng lng, nhiu chng c v.1.2. Tnh cht nui cy

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No m cu hiu kh tuyt i, ch mc cc mi trng giu cht dinh dng nhthch mu, thch chocolat, Thayer - Martin 370C kh trng 5 -10% CO2. Khun lc tothnh sau 24 gi, nh, trn, li, bng, m u, mu xm.1.3. Tnh cht sinh ha

Oxydase dng tnh, catalase dng tnh, glucose dng tnh khng sinh hi, maltose

dng tnh, sacharose m tnh.1.4. Cu trc khng nguynNo m cu c cc thnh phn khng nguyn sau

1.4.1. Khng nguyn v: bn cht polysaccharide, c tnh cht c hiu nhm. Da vo khngnguyn ny, no m cu c chia thnh nhiu nhm huyt thanh: A, B, C, 29-E, H, I, K,L,W-135, X, Y, Z. Khng nguyn polysaccharide ca no m cu c phng thch ra trongdch no ty trong thi k u ca bnh nn c th chn on sm bnh bng cch xc nhkhng nguyn ny trong dch no ty.1.4.2. Khng nguyn vch: bn cht protein, nm mng ngoi cng ca ca vch t bo vikhun, c tnh c hiu typ. No m cu nhm B c 12 typ.1.5. Sc khng

No m cu c sc khng km. Rt d cht, trong bnh phm nc no ty n chsng khong 3-4 gi sau khi ra khi c th. D b cht bi nhit (60 0C trong 10 pht).2. Kh nng gy bnh

No m cu thng sng vng t hu m khng gy nn triu chng, trng thingi lnh mang trng c th ko di trong t ngy n nhiu thng. Trong nhng iu kinkhng thun li cho c th nh mc khng m, cm lnh vi khun i vo mu s gy nnvim mng no m. Him hn, n c th gy nn nhim khun huyt ti cp rt nng, vi stcao, pht ban, t vong cao do xut huyt thng thn. Rt him khi nhim khun huyt do nom cu tr thnh mn tnh v ko di nh st khng r cn nguyn.3. Chn on vi sinh vt

- Nhum soi: bnh phm l mu, dch no ty. Nhum Gram v nhum xanh mtylen kho st bch cu v tm song cu Gram m, hnh ht c ph.

- Phn lp nui cy vi khun: ng thi cy bnh phm ln thch mu hoc thanhchocolat, 370C bnh c 5-10% CO2. Phn lp v nh danh da vo tnh cht hnhth, tnh cht khun lc v s ln men cc loi ng: glucose dng tnh khng sinhhi, maltose dng tnh, sacharose m tnh.

- Tm khng nguyn polysaccharide trong nc no ty bng k thut in di mindch i lu vi khng huyt thanh mu th c th chn on trong giai on sm.4. Phng bnh v iu tr4.1. Phng bnh4.1.1. Phng bnh khng c hiu: cho tr em mc m v ma lnh, pht hin ngi lnh

mang trng, pht hin sm v cch ly bnh nhn. Nhng ngi tip xc vi bnh phi choung khng sinh phng, thng dng rifampicin.4.1.2. Phng bnh c hiu: Hin nay vaccine hn hp bao gm khng nguyn polysaccaridet 4 nhm no m cu A, C, Y v W-135 t ra rt hiu qu trong phng bnh.4.2. iu tr

iu tr bng khng sinh thch hp sm v liu lng cao. Cc khng sinh thngdng l peniciline, chloramphenicol, cc cephalosporin... Cc sunfamit thm qua mng no ttnhng t l no m cu khng thuc ny cao nn khng c dng mt mnh iu tr nom cu.V. LU CU (NEISSERIA GONORRHOEAE)1. c im sinh vt hc

1.1. Hnh th

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Ging nh no m cu, lu cu l cu khun Gram m hnh ht c ph, kch thc 0,8x 0,6 m, thng xp thnh i. Trong lu cp tnh, lu cu thng rt nhiu v nm trong

bch cu a nhn. Trong lu mn tnh lu cu t hn thng nm ngoi t bo.1.2. Tnh cht nui cy

Nui cy kh khn v khi ra ngoi c th vi khun rt d cht, cn phi cy ngay vo

mi trng. Lu cu ch mc mi trng giu cht dinh dng nh thch chocolat, thchThayer-Martin. Vi khun pht trin tt trong iu kin hiu kh pH 7,2-7,6, nhit 35-360C v kh trng c 5-10% CO2. Khun lc sau 48 gi nh, trn, dt, mu xm nht.1.3. Tnh cht sinh ha

Oxydase dng tnh, catalase dng tnh, glucose dng tnh khng sinh hi, maltosem tnh, sacharose m tnh.1.4. Sc khng

Lu cu c sc khng km, cht nhanh khi ra khi c th. Trong bnh phm, vikhun cht nhit phng trong 1-2 gi, nhit 58 0C trong1 gi. Dung dch nitrat bc1% git cht lu cu trong vng 2 pht.1.5. Cu trc khng nguyn

Lu cu c nhiu khng nguyn c hiu nhm v typ. Trong thc t, cc khngnguyn khng gip ch g cho vic xc nh vi khun.2. Kh nng gy bnh

Lu cu ch tm thy ngi, khng tm trong thin nhin. Ngi mc bnh do lytruyn trc tip qua ng sinh dc, qua da, nim mc, gic mc. N gy vim niu o (bnhlu) c nam v n. N cn gy nhim khun nhng b phn khc nhau ca ng sinhdc: nam gy vim tin lit tuyn, vim mo tinh v n gy vim c t cung, vim tcung, vim vi trng. Ngoi ra, lu cu c th gy nhim khun cc c quan khc nhnhim khun huyt a n nhim khun khp, vim mng trong tim, vim kt mc.

tr s sinh, c th xy ra vim kt mc do lu cu khi i qua ng sinh dc ca mb bnh, nu khng iu tr kp thi c th gy m la.3. Chn on vi sinh vt3.1. Chn on trc tip

- nam, ly m niu o lc sng sm trc khi i tiu ln u tin trong ngy.- n, ly m l niu o, c t cung, cc l ca tuyn m o.

3.1.1. Nhum Gram- Chn on bnh lu cp tnh: soi knh hin vi tiu bn nhum Gram, nu c nhiu

bch cu a nhn trung tnh v nhiu song cu Gram m ni bo th c th xc nh bnh nhnmc bnh lu.

- Chn on bnh lu mn tnh: trn tiu bn nhum gram bnh phm, thng t thylu cu v lu cu nm ngoi bch cu a nhn, c th c nhiu tp khun khc, cn nui cy

xc nh vi khun.3.1.2. Chn on bng k thut PCR3.2. Nui cy: Trong c hai trng hp cp v mn, cn cy bnh phm vo mi trng thchhp, phn lp v nh danh vi khun nh vo tnh cht nui cy v sinh ho.3.2. Chn on huyt thanh

- Tm khng th khng lu bng khng th n dng gn hunh quang.- Tm IgM bng ELISA chn on lu ngoi ng sinh dc.

4. Phng bnh v iu tr4.1. Phng bnh

Lu cu khng to nn min dch bo v sau khi khi bnh. Ch yu pht hin bnh viu tr trit , ci thin hon cnh x hi. i vi tr s sinh phng nga vim kt mc

do lu cu, sau khi tr lt lng nh mt git nitrat bc 1%.4.2. iu tr

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Hin nay, xut hin nhng chng lu cu khng vi penicillin G, do cn philm khng sinh la chn khng sinh thch hp cho vic iu tr bnh. Tuy nhin trongthc t, penicillin G vn l khng sinh thng dng v nhiu trng hp cho kt qu tt.

Ngoi ra khng sinh nh ampicillin, oxacillin, spectinomycin, cefoxitin, rifamycin cng dngiu tr tt bnh lu. Cn iu tr trit trnh chuyn sang lu mn tnh. i vi lu mn

tnh, chn on kh v iu tr phc tp, tn km.H VI KHUN NG RUT

(Enterobacteriaceae)

Mc tiu hc tp

1. Trnh by c i cng v h vi khun ng rut.

2. Trnh by c cc c im sinh vt hc v kh nng gy bnh ca cc vi khun E.coli,Salmonella, Shigella, Klebsiella v Proteus.

3. Nu c phng php chn on vi sinh vt, nguyn tc phng v iu tr bnh i viE.coli, Salmonella, Shigella, Klebsiella v Proteus.

I. I CNG V H VI KHUN NG RUT1. Ni c tr

Cc vi khun ng rut thng sng ng tiu ha ca ngi v ng vt, c thgy bnh hoc khng gy bnh. Ngoi ra chng c th sng ngoi cnh (t, nc) v trongthc n.

2. Hnh th

Cc vi khun thuc h Enterobacteriaceae l nhng trc khun gram m khng sinh

nha bo. Mt s ging vi khun thng khng di ng (Klebsiella, Shigella), mt s vi khunkhc di ng nh c lng xung quanh thn t bo. Mt s ging c v nhn thy c nhknh hin vi thng nhKlebsiella.

3. Nui cy

Cc vi khun ng rut hiu kh k kh ty tin, pht trin c trn cc mi trngnui cy thng thng.

Trn cc mi trng c, cc khun lc ca cc vi khun ng rut thng nhn,bng (dng S). Tnh cht ny c th bin i sau nhiu ln nui cy lin tip thnh cc khunlc c b mt kh v x x (dng R).

Cc khun lc ca cc vi khun c v nh Klebsiella l khun lc nhy, ln hnkhun lc dng S v c xu hng ha ln vo nhau.

Nghin cu cc tnh cht sinh vt ha hc gip cho vic nh loi vi khun.

4. Tnh cht sinh vt ha hc

Cc vi khun thuc h Enterobacteriaceae ln men glucose, c sinh hi hoc khngsinh hi, oxidase m tnh, catalase dng tnh, kh nitrate thnh nitrite. Ln men hoc khngln men mt s ng (v d lactose). C hay khng c mt s enzymeeee nh urease,tryptophanase. Kh nng sinh ra H2S khi d ha protein, axt amin hoc cc dn cht c luhunh...

5. Cu trc khng nguyn

cc vi khun ng rut ngi ta c th phn bit:Cc khng nguyn thn hoc khng nguyn O

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Cc khng nguyn lng hoc khng nguyn H

Cc khng nguyn b mt (v hoc mng bc) c gi l khng nguyn K.

Vic nghin cu cc khng nguyn khc nhau ny cho php phn chia cc vi khunthuc cng mt loi hoc mt ging ra cc type huyt thanh.

5.1 Khng nguyn O

L khng nguyn nm trong vch t bo vi khun, bn cht l lipopolysaccharide(LPS) bao gm:

Thnh phn protein lm cho phc hp c tnh cht khng nguyn.

Thnh phn polysaccharide quyt nh tnh c hiu ca khng nguyn.

Thnh phn lipid A chu trch nhim v tnh c.

Khng nguyn O (LPS) l ni c t, khi tim cho ng vt, n gy ra cc phn nggim bch cu, st v nhim c. Cc phn ng ny u thy bnh nhn mc bnh thnghn v sc ni c t.

C th ngi hoc ng vt p ng li vi khng nguyn O bng khng th O. Khng

nguyn O khi gp khng th tng ng s xy ra phn ng ngng kt gi l hin tng ngngkt O: thn vi khun ngng kt vi nhau di dng nhng ht nh, lc kh tan.

5.2. Khng nguyn H

L khng nguyn ca lng ch c nhng vi khun di ng v c bn cht l proteinging nh myosin ca c. Khng nguyn H kch thch c th hnh thnh khng th H v khigp nhau s xy ra hin tng ngng kt H, trong cc vi khun ngng kt li vi nhau docc lng kt dnh li to nn cc ht ngng kt rt d tan khi lc.

Cc vi khun di ng khi cho tip xc vi cc khng th H tng ng th chng b btng.

5.3. Khng nguyn b mt

L khng nguyn bao quanh thn ca vi khun hoc di dng mt ci v nhn thyc r rng knh hin vi thng (v d khng nguyn K ca Klebsiella) hoc l di dngmt mng bc khng nhn thy c knh hin vi thng (v d khng nguyn Vi caSalmonellatyphi)

6. Phn loi

C nhiu cch phn loi h Enterobacteriaceae. Theo cch phn loi ca BergeysManual (1984) chia Enterobacteriaceae lm 13 ging chnh nh sau:

Cc ging : I. Escherichia II. Shigella

III. Edwardsiella IV. Citrobacter

V. Salmonella VI. KlebsiellaVII. Enterobacter VIII. SerratiaIX. Proteus X. ProvidenciaXI. Morganella XII. YersiniaXIII. Erwinia

Trong cc ging k trn th cc ging vi khun c ngha y hc nht l :Escherichia;Shigella; Salmonella; Klebsiella; Enterobacter; Proteus; Yersinia; cn cc ging khc t ngha

II. ESCHERICHIA COLIEscherichia coli (E.coli) l nhng vi khun k sinh, bnh thng c rut, nhng

ng thi cng l tc nhn gy bnh khi chng xm nhp vo cc c quan khc nh ng

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niu, ng mu..., v c mt s chng E. coli c kh nng gy bnh a chy nh ETEC,EPEC, EIEC...

1. c im sinh vt hc

1.1. Hnh th

E.coli l trc khun gram m, di ng do c lng quanh thn, mt s chng E.coli cv polysaccharide, khng sinh nha bo.

1.2. Tnh cht nui cy

E.coli l vi khun hiu kh hoc k kh khng bt buc, pht trin d dng trn cc mitrng nui cy thng thng, mt s c th pht trin c mi trng tng hp n gin.

Nhit thch hp 370C, pH thch hp l 7 - 7,2.

1.3. Tnh cht sinh vt ha hc

E.coli ln men nhiu loi ng sinh axit v sinh hi nh: Glucose, lactose, ramnose;indol dng tnh, methyl dng tnh, VP m tnh, citrat m tnh, urease m tnh, H2S mtnh.

1.4. Khng nguyn caE.coliE.coli c rt nhiu type huyt thanh m cng thc da vo s xc nh khng nguyn

thn O, khng nguyn v K v khng nguyn lng H.

Khng nguyn O : C khong 150 yu t khc nhau v mt huyt thanh.

Khng nguyn K : c chia ra thnh loi L, A hoc B ty theo sc khng i vinhit. C chng 100 khng nguyn K khc nhau.

Khng nguyn H : xc nh c khong 50 yu t H.

2. Kh nng gy bnh cho ngi

E.coli l thnh phn vi khun hiu kh ch yu rut ca ngi bnh thng. S cmt caE.coli ngoi cnh v trong thc n chng t c s nhim bn do phn. Tuy th vaitr gy bnh ca n c ni ti t lu.E.coli c th gy nhim khun nhiu c quantrong c th ngi.

2.1. Bnh tiu chy doE.coli

CcE.coli gy bnh tiu chy ngi gm c:

2.1.1. EnterotoxigenicE.coli (ETEC)

L loi E.coli sinh c t rut. ETEC l mt nguyn nhn quan trng gy tiu chynng ging triu chng do Vibrio cholerae 01 gy ra ngi. Bnh tiu chy do ETEC xy rach yu cc x nhit i v c th gp cc la tui khc nhau, nhng c bit tr nhthng thy bnh cnh lm sng nng d dn ti tnh trng kit nc v ri lon in gii.ETEC cn l mt nguyn nhn thng gy tiu chy cho khch du lch t cc nc pht trinsang cc nc ang pht trin.

C ch gy bnh: ETEC vo rut s gn vo nim mc rut nh cc yu t bm dnh,ng thi sn sinh ra c t rut tc ng ln t bo nim mc rut gy xut tit ra mt slng ln mt cht dch ng trng vi huyt tng. Bnh nhn nn, tiu chy lin tc, phnln c au nhc bp c, au bng v st nh.

C hai loi c t rut c nghin cu k v tnh cht sinh l, sinh ha v tnhtruyn bng plasmid l :

c t rut LT (Heat - labile)

c t rut ST (Heat - stable)

Nhng chng ETEC c th sinh ra mt hoc hai loi c t rut ty thuc vo plasmidm chng mang.

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LT loi c t rut b hy bi nhit, l mt protein gm 2 tiu phn A (Active) v B(Binding) c chc nng ring bit. Tiu phn A c hai tiu n v A1 v A2, tiu phn B c 5tiu n v B1, B2, B3, B4 v B5. Cc tiu n v B c chc nng gn vi th th gangliosideGM1 b mt t bo biu m rut v chun b m ng cho tiu phn A m ch yu l A 1xm nhp vo bn trong t bo. Tiu n v A tc ng ti v tr ch mt trong mng bo

tng ni iu ha enzymee adenylate cyclase. Adenylate cyclase b hot ha v lm tnghm lng adenosine monophosphate vng (AMP vng). Hin tng ny dn ti s tngthm ca cc in gii v nc qua mng rut, gy tiu chy cp v kit nc, ri lon ingii.

ST, loi c t rut khng nhit, l mt phn t c trng lng thp nht v khng ctnh khng nguyn. Th th dnh cho ST khc vi th th LT. Sau khi gn vi th th, STs hot ha guanylate cyclase trong t bo nim mc rut. Hin tng ny dn ti s tngguanosine monophosphate vng (GMP vng) v do xy ra tnh trng tng tit dch rut.

2.1.2. EnteropathogenicE.coli (EPEC)

EPEC hin nay c bit gm mt s type huyt thanh thng gy bnh tiu chy cp

(bnh vim d dy - rut) tr em la tui nh (tr di mt tui), c th gy thnh dch. Ccv dch do EPEC thng hay gp trong bnh vin, c ch gy bnh ca EPEC cha c bitr. Cc EPEC phn lp t cc v dch thng l thuc cc typee huyt thanh:

O26 : B6 O111 : B4 O126 : B16

O55 : B5 O119 : B4 O127 : B18O86 : B7 O125 : B15 O128 : B12

2.1.3. EnteroinvasiveE.coli (EIEC)

L loiE.coli gy bnh bng c ch xm nhp t bo biu m nim mc rut, gy tiuchy ngi ln v tr em vi nhng triu chng bnh l ging Shigella: ngha l au bngqun, mt rn, i tiu nhiu ln, phn c nhiu mi nhy v mu.

Ngi ta chng minh c rng kh nng xm nhp t chc rut ca EIEC cchi phi bi plasmid. EIEC c th khng ln men lactose, khng di ng v ging Shigella vnhiu mt k c cu trc khng nguyn. Do vy nhng v dch tiu chy do EIEC gy nn d

b ln ln vi tiu chy do Shigella.

2.1.4. EnteroadherentE.coli (EAEC)

L loiE.coli bm dnh ng rut gy bnh do bm vo nim mc v lm tn thngchc nng rut.

2.1.5. EnterohemorrhagicE.coli (EHEC)

EHEC l mt trong nhng tc nhn gy tiu chy c th dn ti vim i trng xuthuyt v hi chng tan mu - ure huyt. EHEC l nhng chng E.coli c kh nng sn xutmt c t gy c t bo Vero (Verocytotoxin), gi l VT.2.2. Cc nhim khun khc doE.coli

E.coli c th gy nn nhim khun ng tit niu: s ng nc tiu do si, thainghn... to iu kin thun li cho bnh nhim khun ng tit niu d xy ra . Mt khc,khi thng niu o, ngi ta c th gy ra nhim khun ngc dng.

E.coli c th gy ra nhim khun ng sinh dc, nhim khun gan mt, vim mngno tr cn b, nhim khun huyt ...

3. Chn on vi sinh vt

Ch yu l chn on trc tip phn lp vi khun t bnh phm.

Trong bnh tiu chy do E.coli th cy phn phn lp vi khun. Gia cc nhmE.coli khng th phn bit c bng cc th nghim sinh vt ha hc. i vi EPEC th xc

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nh type huyt thanh bng cc khng huyt thanh mu. i vi ETEC thng c xc nhbng cc th nghim tm kh nng sinh c t rut thng thng nht l tm c t rut bngth nghim ELISA. i vi EIEC cn xc nh tnh xm nhp, c th dng th nghimSereny xc nh. i vi EHEC tm kh nng sinh verocytotoxin.

Trong nhim khun ng tit niu th ly nc tiu gia dng ca bnh nhn nui

cy. Ch nui cy khi nhum soi knh hin vi cn nc tiu thy nhiu bch cu a nhn cngvi vi khun. Cn phi nh lng vi khun trong 1 ml nc tiu c th khng nh vai trgy bnh ca vi khun phn lp c nc tiu.

4. Phng bnh v cha bnh

Hin nay cha c vaccine c hiu. Ch yu l phng bnh chung m ch yu l tntrng cc ni quy v v sinh.

Qua nhiu cng trnh nghin cu cho thy mt s ln cc chng E.coli gy bnh khng cc khng sinh v hin tng mt chng vi khun E.coli khng vi nhiu loi khngsinh cng kh ph bin. Do vy nn da vo kt qu ca khng sinh la chn khngsinh thch hp trong cha bnh.

III. SHIGELLAShigella l tc nhn gy ra bnh l trc khun ngi.

1. c im sinh vt hc

Shigella l trc khun Gram m tnh, khng c lng, v vy khng c kh nng ding, khng c v khng sinh nh bo.

Shigella ln men glucose khng sinh hi, ln men manitol (tr Shigella dysenteriaekhng ln men manitol), hu ht Shigella khng ln men lactose, ch c Shigellasonnei lnmen lactose nhng chm. Khng sinh H2S, Urease m tnh phn ng Indol thay i, phn ng metyl dng tnh, phn ng VP m tnh, phn ng citrat m tnh

Shigella c khng nguyn thn O, khng c khng nguyn H. Cn c vo khngnguyn O v tnh cht sinh ha, ngi ta chia Shigella ra lm 4 nhm:

1.1. Nhm A (Shigella dysenteriae)

Khng ln men manitol, c 10 type huyt thanh c k hiu bng cc ch s Rpt 1 - 10. Cc type huyt thanh trong nhm khng c quan h v khng nguyn vi nhau vcng khng c quan h khng nguyn vi cc nhm khc. Type 1 (Sh. dysenteriae 1) hay cngi l trc khun Shiga l type c ngoi c t.

1.2. Nhm B (Shigella flexneri)

Ln men manitol, c 6 type huyt thanh. Cc type ny c 1 khng nguyn nhm chungv mi mt type huyt thanh li c 1 khng nguyn c hiu type.

1.3. Nhm C (Shigella boydii)Ln men manitol, c 15 type huyt thanh, mi type c khng nguyn c hiu type.

1.4. Nhm D (Shigella sonnei)

Ln men manitol, ln men lactose chm, ch c 1 type huyt thanh.


Shigella gy bnh l trc khun ngi, y l mt bnh truyn nhim c th gythnh cc v dch a phng. Thng tn c hiu khu tr rut gi, trn lm sng biu hin

bng hi chng l vi cc triu chng: au bng qun, i ngoi nhiu ln, phn c nhiu minhy v thng c mu.

Shigella gy bnh bng c ch xm nhp vo t bo biu m ca nim mc rut vnhn ln vi s lng ln trong t chc rut.

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Cc Shigella u c ni c t. Ring trc khun Shiga cn c thm ngoi c t bncht l protein .

Ni c t Shigella cu to nh khng nguyn thn, c c tnh mnh nhng tnhkhng nguyn yu. Tc dng chnh ca ni c t l gy phn ng ti rut.

Ngoi c t ca trc khun Shiga khng ging nh c t rut ca Vibrio cholerae01 v ETEC, hot tnh sinh hc ch yu ca ngoi c t trc khun Shiga l tc dng c ivi t bo.

Vit Nam, Shigella gy bnh l trc khun thng gp nht l nhm B (Shigellaflexneri) v nhm A (Shigella dysenteriae).

Dch t hc: Bnh ly theo ng tiu ha, do n ung phi cc thc n, nc ung bnhim khun. Rui l vt ch trung gian truyn bnh.

Ngi lnh mang vi khun v ngi bnh ng vai tr quan trng gy dch. Dchthng xy ra vo ma h.

Min dch: Ngi ta cho rng khng th dch th khng c hiu lc v thng tn cabnh trn b mt ca ng tiu ha. Ngc li cc min dch ti ch rut c th c mt vaitr quan trng trc ht l cc IgA tit c trong ng rut v cc i thc bo c hotha.


Cy phn l phng php chn on tt nht. Bnh phm cn c ly sm trc khis dng khng sinh, ly ch phn c biu hin bnh l (c mu c nhy) v phi chuyn n

phng xt nghim vi trng nhanh chng. Nui cy phn lp vi khun trn cc mi trngthch hp: mi trng khng c cht c ch (thch lactose) v mi trng c cht c ch(DCA, SS hoc Istrati). Xc nh vi khun da vo cc tnh cht sinh vt ha hc v lm phnng ngng kt vi khng huyt thanh mu ca Shigella.

Trong bnh l trc khun, cy mu khng tm c vi khun.


4.1.Phng bnh

Ch yu l cch ly bnh nhn, kh trng phn v nc thi, pht hin v iu tr ngilnh mang vi khun, p dng cc bin php v sinh v kim tra dch t i vi ngun nc,thc n... Hin nay vn cha c vaccine phng bnh c hiu lc nh mong mun... ang thnghim dng vaccine sng gim c lc ng ung nhm to nn min dch ti ch rut.Vaccine sng ny ch c kh nng bo v c hiu i vi type.

4.2.Cha bnh

Dng khng sinh tiu dit vi khun, vic chn khng sinh thch hp da vo kt qu

khng sinh . Vic s dng khng sinh ba bi, thiu thn trng s c nguy c lm tngnhanh cc chng c sc khng i vi khng sinh v tng nguy c b lon khun vi tt ccc hu qu nghim trng ca n.

IV. SALMONELLAHin nay c ti 2000 type huyt thanh Salmonella khc nhau. Chng gy bnh cho

ngi hoc ng vt hoc c hai. Cc bnh do Salmonella gy ra ngi c th chia thnh 2nhm: thng hn v khng phi thng hn.

1. c im sinh vt hc

1.1. Hnh th

Salmonella l trc khun gram m. Hu ht cc Salmonella u c lng xung quanh

thn (Tr Salmonellagallinarum v Salmonellapullorum), v vy c kh nng di ng, khngsinh nha bo.

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Salmonella ln men glucose c sinh hi (tr Salmonellatyphi ln men glucose khngsinh hi) khng ln men lactose, indol m tnh, methyl dng tnh, VP m tnh, citrat thayi, urease m tnh, H2S dng tnh (tr Salmonellaparatyphi A: H2S m tnh)...

1.3. Cu trc khng nguyn

1.3.1. Khng nguyn O

Mi Salmonella c th c mt hoc nhiu yu t khng nguyn. Hin nay ngi ta bitc 67 yu t khng nguyn O. Vic xc nh cc yu t khng nguyn O l ht sc quan trng nh nhm v nh type.

1.3.2. Khng nguyn H

Ch c nhng Salmonella c lng. Khng nguyn H ca Salmonella c th tn tidi 2 pha: pha 1 c ghi bng ch vit thng a, b, c, d... v pha 2 c ghi bng cc chs rp 1, 2,,,

1.3.3. Khng nguyn Vi

L khng nguyn b mt bao bn ngoi vch t bo vi khun, di dng mt mngmng khng nhn thy c knh hin vi thng. Khng nguyn Vi ch c 2 type huytthanh Salmonellatyphi v S. paratyphi C.

Ngi ta da vo s khc nhau v cu trc khng nguyn xp loi Salmonella. Mts type huyt thanh Salmonella ch yu gy bnh cho ngi bao gm :

Salmonellatyphi : Ch gy bnh cho ngi. nc ta bnh thng hn ch yu do S.typhi gy ra.

Salmonellaparatyphi A : Ch gy bnh thng hn cho ngi v cng hay gp ncta sau S.typhi.

Salmonellaparatyphi B : Gy bnh thng hn ch yu cho ngi, i khi c sc

vt. Bnh thng gp cc nc chu u.Salmonellaparatyphi C : Gy bnh thng hn, vim d dy rut v nhim khun

huyt. Bnh thng gp cc nc ng Nam .

Salmonella typhimurium v Salmonellaenteritidis : Gy bnh cho ngi v gia sc,gp trn ton th gii. Chng l nguyn nhn gy nhim trng, nhim c thc n do n phithc n nhim Salmonella.

Salmonellacholerae suis : Loi ny hay gy nhim khun huyt.


2.1. Bnh thng hn

nc ta, bnh thng hn ch yu do S. typhi, sau n S. paratyphi A, cn S.paratyphi B v S. paratyphi C th t gp. Bnh ly t ngi ny sang ngi khc, qua thc n,nc ung b nhim khun. Sau khi khi bnh v mt lm sng, khong 5% bnh nhn trthnh ngi lnh mang vi khun ko di hng thng hoc hng nm. h, cha Salmonellal ng mt v vi khun vn c tip tc o thi theo phn ra ngoi cnh. Ngi lnhmang vi khun l ngun lan truyn bnh quan trng.

Sinh bnh hc: Trc khun thng hn vo c th qua ng tiu ha n rut non thchui qua nim mc rut ri vo cc hch mc treo rut. chng nhn ln v mt phn vikhun b dung gii, gii phng ra ni c t. Ni c t kch thch thn kinh giao cm bng,gy thng tn mng Peyer, xut huyt tiu ha, c th gy thng rut. Ngoi ra, ni c ttheo mu ln kch thch trung tm thn kinh thc vt no tht ba, gy ra trng thi st ko

di, li b, v gy ra bin chng try tim mch... T cc hch mc treo rut vi khun lan trn

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vo mu gy nn nhim khun huyt v lan i khp c th, ri vi khun vo mt v t quaytr li rut. Vi khun theo phn ra ngoi cnh.

2.2. Cc bnh khc

Cc bnh khng phi thng hn do Salmonella gy ra thng l mt nhim trng giihn ng tiu ha trong cc trng hp nhim trng nhim c thc n m Salmonellatyphimurium... l tc nhn hay gp nht, sau l Salmonellaenteritidis... Nhim trng nhimc do Salmonella c thi gian nung bnh t 10 n 48 gi. Bnh biu hin c st, nn, tiuchy. Bnh khi sau 2 - 5 ngy, khng c bin chng.

Ngoi ra, Salmonella c th gy nn cc tn thng ngoi ng tiu ha nh vimmng no, th nhim trng huyt n thun, nhim trng phi...


3.1. Chn on trc tip

Phn lp vi khun t cc bnh phm nh mu (cy mu), phn (cy phn) v cc bnhphm khc .

3.1.1.Cy muLy 5ml n 10ml mu tnh mch bnh nhn lc st cao cy vo bnh canh thang cmt b, m 370C, sau 24 n 48 gi nu vi khun mc, cn phi kim tra hnh th, tnh cht

bt mu khi nhum Gram, kim tra tnh cht sinh vt ha hc, xc nh cng thc khngnguyn vi cc khng huyt thanh Salmonella mu.

i vi bnh thng hn, nu bnh nhn cha s dng khng sinh th gi tr caphng php cy mu cao. Nu cy mu vo :

Tun l u ca bnh th t l dng tnh t 90%

Tun l th hai ca bnh, dng tnh t 70% - 80%

Tun l th ba, t l dng tnh t 40 - 60%

Nu bnh ti pht, cy mu s tm thy vi khun thng xuyn trong nhiu ngy.3.1.2. Cy phn

Thng dng tnh t tun th 2 tr i. Nui cy phn lp vi khun mi trngtng sinh v mi trng c cht c ch (mi trng SS, DCA, Istrati, Endo...). Xc nh vikhun da vo tnh cht sinh vt ha hc v lm phn ng ngng kt vi khng huyt thanhmu.

Khi nghi ng mt trng hp mc bnh thng hn phi ng thi xt nghim cymu, cy phn v lm huyt thanh chn on.

Cy phn l bin php duy nht chn on vi sinh vt trong trng hp ng cthc n nghi do Salmonella v trong vic xc nh ngi lnh mang mm bnh.

3.1.3. Cy cc bnh phm khc

Vi khun thng hn cn c th phn lp bng cch cy ty xng, nc tiu, dcho ban, dch mt ca bnh nhn.

3.2. Chn on huyt thanh

Sau khi nhim Salmonella t 7 n 10 ngy, trong mu bnh nhn xut hin khng thO ca Salmonella, sau ngy th 12 n ngy th 14 xut hin khng th H. Khng th O, tnti trong mu trung bnh 3 thng, khng th H tn ti 1 n 2 nm.

Ly huyt thanh cc bnh nhn tm khng th ngng kt ca Salmonella bng phnng ngng kt Widal.

Trong bnh thng hn, chn on huyt thanh (Widal) t tun l th hai, lm 2 lncch nhau mt tun l tm ng lc khng th.

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4.1. Phng bnh

Thc hin cc bin php v sinh v phn, nc, rc, tch cc dit rui. Phi n chn,ung si, ra tay trc khi n... Qun l cht ch bnh nhn. Pht hin ngi lnh mang mm

bnh iu tr trit .

Tim vaccine T.A.B l loi vaccine cht. Mt s nc dng vaccine thng hn snggim c lc v vaccine chit t khng nguyn Vi ca Salmonella.

4.2. Cha bnh

Dit vi khun Salmonella bng khng sinh. Nhng thuc khng sinh thng dng lchloramphenicol, ampicillin vi liu lng thch hp trnh bin chng tru tim mch vthuc dit vi khun lm gii phng ra qu nhiu ni c t. Tuy nhin ngy nay cng xuthin nhng chng Salmonella khng vi cc khng sinh trn, v vy cn lm khng sinh chn khng sinh thch hp.

V. KLEBSIELLA PNEUMONIAE

LoiKlebsiella c nhiu type c kh nng gy bnh cho ngi nh:-Klebsiella pneumoniae: Thng gy ra cc bi nhim ng h hp.

-Klebsiellarhinoscleromatis : Gy bnh x cng mi.

-Klebsiellaozenae: Gy bnh tr mi

Klebsiella pneumoniae hay cn gi l ph trc khun Friedlander l loi vi khun rtph bin trong thin nhin (nc, t), n k sinh ng h hp trn ca ngi, l tc nhngy bnh c hi.

1. c im sinh vt hc

1.1. Hnh th

Trong bnh phmK. pneumoniae c hnh trc khun ngn, gram m, bt mu m hai cc, vi khun ny c nhiu hnh th, c khi nh cu khun, c khi li hnh di, c v,khng di ng, khng sinh nha bo.

1.2. Tnh cht nui cy

Vi khun d mc trn mi trng nui cy thng thng. Trn thch dinh dng haythch mu, khun lc ly nhy, mu xm. Trong canh thang, vi khun mc nhanh v c u, ay ng c lng cn.


Ln men nhiu loi ng sinh acid v hi nh : Glucose, lactose, manit. Phn ngindol m tnh, phn ng metyl m tnh, phn ng VP dng tnh, phn ng citrat dng

tnh, urease dng tnh, H2S m tnh.1.4. Cu trc khng nguyn

Khng nguyn thn O : C 5 type

Khng nguyn v K : Bn cht l polysaccharide, mang tnh cht c hiu type, c 72type, trong type 1 v type 2 hay gp nht trong nhim khun ng h hp.


Klebsiella pneumoniae l loi vi khun gy bnh c iu kin gi l gy bnh chi. Nhng nhim trng c hi xy ra ch yu mi trng bnh vin v trn nhng bnhnhn b suy kit, suy gim min dch. Nhng iu kin cc nhim trng c hi xut hinl :

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- Ngy cng c nhiu loi khng sinh ph rng, vic s dng khng sinh rng ri vthiu thn trng lm mt th qun bnh ca vi khun ch bnh thng, ng thi lm cho vikhun c chn lc bi khng sinh v to nn sc khng i vi khng sinh.

- Cc th thut nh ni soi, thng tim... c pht trin v p dng ngy cng nhiutrong cc bnh vin. Khi p dng cc th thut ny c th a vi khun vo c th qua ng

thng...- Nhng bnh nhn m sc khng gim st nghim trng do mc cc bnh lm suy

gim min dch (v d: K mu, suy ty...)

Klebsiella pneumoniae c th gy ra :

Nhim trng ng h hp di nh vim phi, vim ph qun phi th pht sau cm,sau si, sau ho g hoc cc bnh nhn ang hi sc h hp (ang dng my h hp nhnto).

Nhim trng mu : Thng gp nhng bnh nhn b suy kit nh x gan, ung thmu, suy ty...

Ngoi ra cn c th gy nhim trng ng tit niu, ng mt hoc ng sinh dc,vim mng no, vim tai, vim xoang v vim ni tm mc.3. Chn on vi sinh vt

Ch yu da vo chn on trc tip, phn lp vi khun t cc bnh phm m, muv.v... ty theo th bnh. Nui cy ln cc mi trng thch hp phn lp v xc nh vikhun da vo hnh th, tnh cht nui cy c bit (khun lc nhy, dnh), tnh cht sinh vtha hc, kh nng gy bnh thc nghim. Xc nh type bng phn ng ngng kt hoc phnng phnh v vi khng huyt thanh c hiu type.


4.1. Phng bnh

Cha c vaccine phng bnh c hiu. Ch yu l trnh nhng iu kin thun li chonhim trng c hi xut hin bng cch nng cao sc khng ca ngi bnh v d phngtt cc nhim trng bnh vin.

4.2. Cha bnh

Da vo kt qu ca khng sinh chn khng sinh cng hiu. Klebsiellapneumoniae thng c sc khng cao vi khng sinh.

VI. PROTEUSGingProteus k sinh rut v cc hc t nhin ca ngi (v d : ng tai ngoi).

Chng l loi vi khun gy bnh c hi

1. c im sinh vt hc

1.1. Hnh thTrc khun gram m, rt di ng. Vi khun c nhiu hnh th thay i trn cc mi

trng khc nhau, t dng trc khun n dng hnh si di.

1.2. Tnh cht nui cy

Vi khun mc d dng trn cc mi trng nui cy thng thng. Trn mi trngthch dinh dng, khun lc c mt trung tm lan dn ra, tng t, tng t , mi t l mtgn sng v c mi thi c bit.

Trn mi trng c natri deoxycholate:Proteus mc thnh khun lc trn, ring bitkhng gn sng, c mt im en trung tm, xung quanh mu trng nht.


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Khng ln men lactose. a s Proteus : H2S dng tnh v urease dng tnh. Davo tnh cht sinh vt ha hc ngi ta phn loi ging Proteus thnh cc loi: Proteusmirabilis,Proteusvulgaris,Proteusmyxofaciens,Proteuspenneri.

1.4. Cu trc khng nguyn

Cu trc khng nguyn ca Proteus rt phc tp v khng c vn dng vo cngtc thc t hng ngy. Ngi ta thy c mt mi tng quan c bit gia khng nguyn Oca mt s chngProteus (c gi l OX2 ; OX19; OXK) vRickettsia. V vy, ngi ta dngcc chng ny lm khng nguyn trong chn on huyt thanh bnh do Rickettsia (phnng Weil - Felix).

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2. Kh nng gy bnh

Proteus l mt loi vi khun "gy bnh c hi". Chng c th gy ra : -Vim tai gia c m

- Vim mng no th pht sau vim ti gia tr cn b.

- Nhim khun ng tit niu- Nhim khun huyt ...


Phn lp vi khun t cc bnh phm nh : m tai, nc tiu, mu ... ty theo th bnhlm sng. c im ca cc tn thng v m do Proteus gy ra c mi thi nh trong hoith do vi khun k kh gy nn. Nui cy trn cc mi trng thng thng. Xc nh vikhun da vo hnh thi khun lc gn sng, mi thi c bit trn da mi trng v trckhun Gram m urease dng tnh v mt s tnh cht sinh vt ha hc khc.

Mun phn lp thnh khun lc ring r th nui cy trn mi trng c Natridesoxycholat,Proteus s mc thnh khun lc ring bit c chm en gia sau 48 gi.

4. Phng bnh v cha bnh4.1. Phng bnh

Nng cao th trng ngi bnh, khi p dng cc th thut thm khm phi tuyt i vtrng d phng tt cc nhim trng bnh vin...

4.2. Cha bnh

S dng khng sinh da vo kt qu ca khng sinh . Vi khun ny thng c sc khng cao vi khng sinh.

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VI KHUN DCH HCH VLEGIONELLA PNEUMOPHILA

Mc tiu hc tp1. Trnh by c c tnh sinh vt hc ca vi khun dch hch v Legionella pneumophila

2. Trnh by c kh nng gy bnh ca hai vi khun ny

3. Trnh by c phng php chn on sinh vt hc, phng php phng nga v iu tr

I. VI KHUN DCH HCH (Yersinia pestis)Yersinia pestis thuc ging Yersinia, thuc h vi khun ng rut

(Enterobacteriaceae)

Trc khun dch hch c A. Yersin phn lp nm 1894 trong mt v dch hch Hng Kng. Nm 1896, Lehmann v Neumann t tn cho vi khun ny l Bacterium pestis.

Nm 1944, Van Loghen chuyn chng sang ging Yersinia ghi cng ca A. Yersin.

Vi khun dch hch gy nn bnh dch hch l bnh ca mt s loi ng vt (ch yu lcc loi chut), ly sang ngi qua b cht, c bnh thin nhin, d pht thnh dch ln.Dch hch l bnh ti nguy him, c xp vo nhm 4 bnh thuc din phi khai bo bt

buc: dch hch, dch t, u ma v st vng.

nc ta, bnh dch hch c pht hin ln u tin nm 1898 Nha trang, sau bnh pht trin mnh min Nam. Hin nay vn cn mt s dch hch ch yu vng Tynguyn.

1. c im sinh vt hc

1.1. Hnh thi v tnh cht bt mu

Vi khun dch hch l trc khun ngn, hnh bu dc nh, kch thc 0,5 -0,8 x 1-2

m, Gram m, bt mu m hai u, nht l khi nhum Wayson hay xanh methylen. Trongbnh phm vi khun ng ring l hoc xp i v c v. Trong mi trng nui cy 37oCth c v, nu nui cy 28oC th khng c v. Khng sinh nha bo, khng di ng.

1.2. Tnh cht nui cy

Trc khun dch hch d mc trn cc mi trng nui cy thng thng, nhngchm. Hiu k kh tu tin, nhit thch hp l 28oC.

- Trn canh thang Yersinia pestis lc u lm c u nh, dn dn sau 24 - 48 gi vikhun pht trin to mt vng mng trn b mt v lng cn di y, canh thang tr nntng i trong.

- Trn thch thng: vi khun mc chm to khun lc rt nh (0,1mm) sau 24 gi. Sau48 - 72 gi 280C, ng knh mi t c 1- 1,5 mm, b tri mng ra, khng u, trungtm li, hi trong, mu xm nht.


Vi khun dch hch khng di ng. Oxydase m tnh, catalase dng tnh. Ln menng glucose khng sinh hi, manitol dng tnh, ONPG dng tnh, c enzyme Dnase, khnitrat thnh nitrit. Citrat simmon thay i tu theo chng, lactose m tnh, rhamnose m tnh,saccharose m tnh. Indol m tnh, Voges Proskauer m tnh, khng to enzyme urease,khng sinh H2S, ornithin decarboxylase (ODC) m tnh, lysin decarboxylase (LDC) m tnh,arginin dihydrolase (ADH) m tnh. Vi khun dch hch b ly gii bi phage c hiu.

1.4. Sc khng

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Vi khun b tiu dit 550C/30 pht hoc 1000C/1 pht. Trong iu kin kh hanhhoc phi nng vi gi vi khun c th cht. Trong cc t chc, trong xc chut, t m,trong nc vi khun c th tn ti t vi chc ngy n vi thng.

1.5. Khng nguyn v cc yu t gy bnh

- Khng nguyn v: Cn gi l khng nguyn F1 (Fraction 1), c trong iu kin nuicy vi khun 37oC hoc trong bnh phm ca c th ang b bnh. Bn cht l protein.Khng nguyn v gip cho vi khun chng li hin tng thc bo.

- Khng nguyn V v W: L mt phc hp gm protein V v lipoprotein W. Cc khngnguyn ny lin quan n kh nng chng li hin tng thc bo.

- Khng nguyn thn: l khng nguyn chung vi cc vi khun h ng rut.

- c t: vi khun dch hch c 2 loi c t :

+ Ni c t: bn cht l Lipopolysaccharide gn lin vi vch t bo vi khun, gy racc triu chng st trong bnh dch hch.

+ c t chut (murine toxin) bn cht l protein nh mt ngoi c t, c tc ng lm

tan hng cu, c hot tnh trn h thng mch mu gy ra mu v gy sc.2. Kh nng gy bnh

2.1. Dch t hc

Bnh dch hch l bnh ca loi gm nhm hoang di, trong loi chut Rattus vi 2chng: chut ng v chut nh c vai tr quan trng nht. Ngi ch l vt ch ngu nhinmc phi do b b cht nhim khun t.

- cha: Cc loi gm nhm hoang di

- Cn trng mi gii: Ch yu l cc loi b cht Xenopsylla cheopis, ngoi ra c thgpXenopsylla astia v cc cn trng ht mu nhPulex irritans ...

- i tng cm th: ng vt gm nhm hoang di v c th ly sang ngi.

ng truyn bnh: u tin dch xy ra cc loi gm nhm hoang di ri truyn nchut ng, chut nh, sau truyn sang ngi l con ng hay gp nht hoc ngi ti

bnh hoang di cng c th b b cht nhim khun t v mc bnh. Bnh dch hch c thtruyn t ngi bnh sang ngi lnh do chy rn hoc c th truyn bnh trc tip t ngisang ngi nu ngi mc bnh dch hch th phi.

cha

(gm nhm hoang di)

Cn trng mi gii

Chut

Cn trng mi gii

Ngi Ngi

Chy, rnHnh 1: S dy chuyn dch t

110

- Xennopsylla cheopis- Xenopsylla astia- Pulex irritans

- Rui ht mu

- Chut ng- Chut nh

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2.2. Gy bnh cho ngi

Vi khun dch hch sau khi vo c th s vo h thng bch huyt v nhn ln tronghch, sau vo mu, ri c tr gan, lch, thn v cc hch su.

Thi gian bnh t 3- 6 ngy, i khi ngn hn, ty thuc vo sc khng ca cth v c lc ca vi khun.

Bnh dch hch c 3 th lm sng:

- Th hch: Sau khi b b cht nhim khun t, ti ni t ni mn nc, i khi en gia. Vi khun xm nhp vo hch bch huyt gn vt t nht lm cho hch sng to, rn,dnh cht khng di ng v rt au. Bnh nhn st cao, mt v chng mt, triu chng nhimc nng. Nu khng c iu tr kp thi, bnh nhn s t vong vo ngy th 5 hoc th 6ca bnh v nhim khun huyt. Th hch l th lm sng thng gp nht.

- Th phi: C th nguyn pht do ly trc tip qua th phi ca ngi bnh hoc l thpht sau th hch. Bnh khi pht t ngt, st cao, ho, au lng ngc, m c mu. Bnhtin trin nhanh v rt nng, t vong sau 2 - 3 ngy nu khng c iu tr kp thi. Th phirt d ly lan.

- Th nhim khun huyt: C th l tin pht, nhng thng do bin chng ca th hchv th phi nguyn pht, gy thng tn c m da, mn xut huyt v huyt niu, st cao,cy mu dng tnh. T vong sau 2 - 3 ngy.


3.1. Chn on trc tip : Bnh phm l dch chc hch trong th hch, mu trong th nhimkhun huyt, m trong th phi.

T bnh phm lm tiu bn nhum gram (i vi th hch) hoc xanh methylen hocWayson. Phng php nhum trc tip c gi tr kt hp vi triu chng lm sng chng iu tr kp thi.

Mt khc cn nui cy bnh phm vo cc mi trng thch hp nh canh thang,nc pepton, thch mu, thch thng ..., 28 oC . Sau xc nh cc tnh cht sinh vtha hc, nh typ phage v tim truyn sc vt.

3.2. Chn on gin tip : Bnh dch hch l bnh nhim khun cp tnh nn ngi ta khnglm phn ng huyt thanh chn on bnh. Ngi ta thng lm chn on huyt thanh iu tra dch t hc, thng dng phn ng ngng kt hng cu th ng pht hin khngth khng F1.

4. Phng bnh v iu tr

4.1. Phng bnh

4.1.1 Phng bnh c hiu :Hin nay c hai loi vcxin: vc xin sng gim c v vcxin

cht. Vcxin cht tim hai ln, gy min dch c 6 thng. Vc xin sng gim c tim mtln, gy min dch nhanh v thi gian min dch ko di n mt nm. Ch tim vc xin chonhng ngi ang sng vng dch hoc phi lm nhim v nhng vng .

4.1.2. Phng bnh chung: Ct t dy truyn dch t bng cch: dit chut, dit cn trng migii, bnh nhn phi khai bo v cch ly, phong ta khu vc c dch. Khi c dch xy ra cn

phi ung khng sinh d phng cho ngi nh bnh nhn, nhn vin y t tip xc vi thphi.

4.2. iu tr

Vi khun dch hch nhy cm vi cc khng sinh nh streptomyxin, chloramphenicol,tetracyclin, nhng phi iu tr sm. Khng sinh penicilin khng c tc dng.

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II. LEGIONELLA PNEUMOPHILANm 1977 Mac Dade phn lp c t t chc phi ca mt bnh nhn cht v vim

phi mt trc khun Gram m mi m trc khoa hc cha bit. Nm 1978, trc khunny c t tn lLegionella pneumophila.

LoiLegionella pneumophila thuc gingLegionella, hLegionellaceae. Chng c khnng gy bnh ng h hp ngi.1. c im sinh vt hc

1.1.Hnh th

Vi khun a hnh thi, thng gp dng trc khun Gram m (bt mu yu), i khi gphnh cu trc khun hoc hnh si. Kch thc thay i 0,3-0,9 m x 2- 20 m. Hnh ththay i theo nhng iu kin nui cy v mi trng nui cy khc nhau. Vi khun di ng,c mt lng mt u, khng sinh nha bo, khng c v.

1.2.Tnh cht nui cy

Vi khun kh nui cy, hiu kh tuyt i, i hi mi trng giu cht dinh dng vi

mt khong pH hp (chung quanh 6,5), t trong kh trng c 2,5 % CO 2 v nhit t 35-37OC. Mi trng tt nht hin nay phn lp vi khun Legionella pneumophila l mitrng BCYE (Buffered Charcoal Yeast Extract agar), y l mi trng thch c than hatv cao men (cha L- cystein l yu t c bn cho s phn lp Legionella). mi trng nyc cc khun lc rt nh, mu xanh xm d dng quan st knh lp, xut hin vo ngy th 3sau khi cy.

C th nui cyLegionella pneumophila cc nui cy t bo phi g, phi phi ngi,bch cu n nhn to ca ngi, cc t bo HeLa, Hep-2...

Nui cy phi g l phng php tt nht thch hp vi tt c cc Legionella thuccc loi khc nhau.

1.3. Tnh cht sinh vt ha hcOxydase dng tnh yu, catalase (+), lm lng gelatin, urease m tnh v khng lnmen cc loi ng, c kh nng ly gii hippurat natri, th nghim ny dng chn on

phn bit vi ccLegionella khc, sinh ra enzyme -lactamase.

1.4. Khng nguyn

Khng nguyn O c hiu c chia thnh nhiu nhm huyt thanh khc nhau. Khngnguyn H chung vi ccLegionella khc.

1.5. Sc khng

Vi khun d b dit bi tc nhn l ha, nhng li sng lu c trong nc. Vi khunc trong nc t nhin (ao, h), nc cha b v thp nc nhn to. Vi khun c mt

trong h thng dn nc nng lnh, h thng my iu ha nhit , cc ng nc, vi nc...2. Kh nng gy bnh

Legionella pneumophila l nguyn nhn ca bnh l vim phi cp v st Pontiac. Vikhun t mi trng xung quanh vo ngi theo ng h hp do ht phi bi hoc hi ncc nhim khun.

Bnh vim phi cp doLegionella l mt nhim trng cp tnh ng h hp c vimphi nng vi st cao t ngt, ho, au ngc, a chy, li b hoc m sng... Nu khng ciu tr th t l t vong t 10 % - 20 %.

St Pontiac c c trng bi st, rt run, au c v khng c bnh l h hp. Tintrin lnh tnh.

bnh vin c nhng v dch bnh xy ra do Legionella pneumophila nhng bnhnhn b bnh nng hoc c iu tr bng cc thuc c ch min dch.

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Trong nhiu trng hp c nhng nhim trng bn lm sng, ch pht hin c do stng hiu gi khng th c hiu.

Trng hp mc bnh l t, ch yu nhng ngi nghin ht thuc lu nm , b vimph qun mn v nguy c mc bnh nhng ngi b bnh ung th. Bnh xy ra l t khpmi ni trn th gii.

3. Chn on vi sinh vt3.1. Chn on trc tip:Pht hin vi khun trong mu nghim (m, cht dch ph qun,mnh sinh thit phi...) bng phng php min dch hunh quang trc tip, y l phng

php c hiu, cho kt qu nhanh sau mt vi gi.

3.2. Phn lp vi khun:Bnh phm l mu, mnh phi (sinh thit hoc m t thi), dch mngphi, cht ht t ph qun, kh qun...

Vt phm ngoi cnh: ly mu nc.

Bnh phm c cy vo mi trng thch BCYE, 36OC trong kh trng c 2,5%CO2. Vi khun mc sau 48 gi. Quan st khun lc v nh danh vi khun.

Mi trng cy mu c theo di trong 3 tun, nu vi khun mc cy chuyn vo mitrng BCYE.

3.3. Chn on huyt thanh:Dng cc k thut min dch hunh quang gin tip, ELISA pht hin khng th trong huyt thanh bnh nhn. Cn xc nh khng th trong huyt thanhkp, hiu gi ln hn 4 ln mi c gi tr chn on.

4. Phng bnh v cha bnh.

4.1. Phng bnh: Cn x l nc cc b nc, vi nc, iu ha nhit . Cn c nhngbin php ngn nga khng xy ra dch trong bnh vin.

4.2. Cha bnh: Vi khun nhy cm vi nhiu khng sinh nh erythromycin, rifampicin,fluoroquinolon. Cc -lactamin khng c tc dng trn vi khun ny v chng sn xut

enzymee -lactamase.

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HAEMOPHILUS V BORDETELLA

Mc tiu hc tp1.Trnh by c mt s tnh cht vi khun hc ca vikhun Haemophilus v Bordetella.2.Nu ra c kh nng gy bnh ca hai loi vi khun ny.3.Trnh by c mt s phng php chn on vi khun hc i vi Haemophilus v

Bordetella.

I. HAEMOPHILUSGingHaemophilus thuc hPasteurellaceae, gm nhng trc khun nh, Gram m,

khng di ng, khng sinh nha bo, c v lin quan mt thit vi tnh cht gy bnh. Mitrng nui cy bt buc phi c mt hoc c hai yu t pht trin X v V (X:hematin, V: nicotinamidadenin dinucleotid = NAD). Thch chocolat c c hai yu t ny vthch hp cho s pht trin ca nhng Haemophilus i hi c hai yu t X v V. Cc

Haemophilus i hi c hai yu t X v V ch c th pht trin trn mi trng thch mu nu

cho thm yu t V bn ngoi vo.CcHaemophilus k sinh bt buc trn nim mc ng h hp hoc i khi ngsinh dc ca ngi hay ng vt. Thuc nhm ny c nhiu thnh vin, y ch gii thiu

Haemophilus influenzae, tc nhn ch yu gy nhim khun h hp cp tr nh vHaemophilus ducreyi, tc nhn gy bnh h cam.1. Hemophilus influenzae

Haemophilus influenzae do Richard Pfeiffer phn lp ln u tin t mt bnh nhn bcht trong v dch cm ln nm 1892 (nn cn gi l trc khun Pfeiffer). T tr i, trongmt khong thi gian di, ngi ta tin rng n chnh l cn nguyn gy ra bnh cm v t tnlBacterium influenzae. Nm 1933, khi pht hin ra vius cm th cn nguyn ca bnh cmcng nh vai tr caB. influenzae mi c lm sng t: virus cm gy ra bnh cm, cnB.

influenzae l vi khun n theo (second invader) sau khi cc t bo nim mc ng h hp b tn thng nng n bi virus cm.V danh php, thut ng Bacterium influenzae do Lehmann v Neumann xut

nm 1896. Nm 1917, Winslow v cng s, trn c s nhng hiu bit mi v B.influenzae, chuyn chng sang ging Haemophilus, v t n nay, chng mang tn Haemophilusinfluenzae.1.1. c im sinh vt hc

L vi khun a hnh thi, Gram m, khng di ng, khng sinh nha bo. Trong bnhphm vi khun thng c v polysaccharide mang khng nguyn c hiu typ. Trong khi cytruyn trn mi trng nhn to th vi khun mt v. Vi khun hiu kh, i hi CO2 (5 -10%), nhit thch hp l 370C, pH thch hp 7,6 - 7,8. Vi khun ch mc c trn mi

trng thch c c yu t X v V (mc tt trn mi trng thch chocolat), khun lcnh, trong, mt nhn (dng S), ng knh 0,5-0,8 mm, sau khi cy truyn cc khun lctr thnh dng R; khng gy tan mu trn thch mu.

Trong mi trng nui cy H.influenzae, yu t V c th thay th bng NAD hocNADP, yu t X c th thay th bng Hemin hoc Hematin. Cng c th thay th yu tV bng cch cy t cu vng trn mi trng thch mu, cc khun lc trong, nh ca

H.influenzae mc quanh ng cy t cu khun (do t cu vng tit ra yu t V), l thnghim "v tinh" (Satellitism), c s dng khi khng c yu t V trong mi trng nuicyH. influenzae.

H.influenzae ln men ng glucose, khng ln men ng lactose v mannit.H.influenzae khng rt km vi cc yu t ngoi cnh. Trong bnh phm, chng

cht nhanh chng nu b nh sng mt tri chiu trc tip, kh hay lnh. H.influenzae bcc cht st khun thng thng git cht mt cch d dng.

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1.2. Kh nng gy bnh ngiH.influenzae l loi vi khun k sinh bnh thng ng h hp, thng phn lp

c nim mc mi hng ngi lnh vi t l khong 25%. N c th gy nn cc nhimkhun khc nhau:- Nhim khun ng h hp: H.influenzae typ b l mt trong cc tc nhn ch yu gy cc

nhim khun khc nhau ca ng h hp, thng gp tr nh tui . Bnh doH.influenzaethng l th pht (sau si, cm) gm: vim ng h hp trn (thanh qun, tai gia, xoang),vim ng h hp di (vim ph qun cp v mn tnh, vim phi). Vim thanh qun do

H.influenzae typ b l chng bnh t gp nhng rt nghim trng.- Vim mng no m tr em: vim mng no do H.influenzae l mt bnh nng v

c tnh cht cp tnh, cn c chn on v iu tr ngay.- Ngoi raH.influenzae cn gy nhim khun huyt, vim ni tm mc (him), vim

niu o v cc nhim trng sinh dc (m o, c t cung, tuyn Bartholin, vi trng).1.3. Chn on vi sinh vt

Bnh phm: tu theo bnh cnh lm sng m ly bnh phm khc nhau. Bnh phm cth l m, cht nhy mi hng, cht dch kh qun, ph qun hoc dch no ty, m...

1.3.1. Chn on trc tip- Soi ti, nhum gram i vi dch no tu thy c nhiu bch cu a nhn v vi

khun khun gram m a hnh thi.- Tm khng nguyn v typ b trong bnh phm: chn on nhanh cc nhim trng

doH.influenzae typ b gy ra. Dng k thut min dch pht hin khng nguyn typ b trongdch no tu, mu v nc tiu. Cc phng php min dch c p dng l min dch ilu, ngng kt th ng, ng ngng kt v ELISA vi khng th n dng.

- Tm ADN: dng mt on ADN mu nh du phng x hoc dng k thut khuchi gen (PCR: polymerase chain reaction) tm on ADN c trng ca H.influenzae trong

bnh phm.1.3.2. Nui cy

Nui cy bnh phm trn mi trng thch chocolat, bnh kn cha 10% CO2. XcnhH. influenzae bng th nghim "v tinh" vi t cu v th nghim vi cc yu t X v V.1.4. Phng bnh v iu tr1.4.1. Phng bnh

- Phng bnh khng c hiu: vim mng no doH.influenzae typ b l mt bnh ly,bnh nhn cn phi c cch ly. Ngi lnh tip xc vi bnh nhn phi ung khng sinh dphng (Rifampicin).

- Phng bnh c hiu: dng vaccine cha polysaccharit v ca H.influenzae typ b(Hib).1.4.2. iu tr

iu tr cc nhim trng do H.influenzae cn phi da vo khng sinh . Trong khicha c kt qu khng sinh hoc khi khng phn lp c vi khun, chloramphenicol cu tin la chn. Vim mng no cn dng cephalosporin th h 3.2. Haemophilus ducreyi (Trc khun h cam)

c Ducreyi pht hin nm 1889 trong m mn lot c quan sinh dc ca bnhnhn mc bnh h cam, v th c gi l trc khun h cam.

Vi khun c t ch tn thng, phi phn lp trn mi trng c 20 - 30 % mu ti,vi khun ch cn yu t X. Bnh nhn mc bnh h cam c phn ng vi hn dch vi khun bgit cht tim ni b. Phn ng thng xut hin vo ngy th 8 v tn ti rt lu, c gi tr htr chn on.

Bnh ly qua ng sinh dc nn d phng ch yu l quan h tnh dc hp v sinh

v khng quan h vi nhiu ngi. Cha bnh bng khng sinh nh ampicillin,chloramphenicol, bactrim...

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II. BORDETELLA PERTUSSIS (Trc khun ho g )Trc khun ho g thuc gingBordetella, hAlcaligenaceae.

1. c im sinh vt hcB. pertussis hnh trc khun rt nho, kch thc 0,5-0,8 m x 0,2-0,3 m, Gram m,

khng di ng, khng sinh nha bo, c th c v, vi khun hiu kh. Mun phn lp t bnh

phm phi c mi trng c bit, l mi trng Bordet - Gengou (mi trng cha khoaity, glycerol v 15-20% mu), vi khun mc chm sau 2 - 4 ngy, khun lc nh, trn, li,xm nht nh x c hoc c nh kim loi (ging nh git thy ngn), xung quanh c vng tanmu hp. Catalase m tnh, Oxydase dng tnh, Urease m tnh. Trong qu trnh nui cytrn mi trng nhn to, trc khun ho g bin d t dng S sang dng R. Hin tng nyc chia lm 4 pha :

- Pha I: Tng ng vi khun lc dng S, vi khun hnh bu dc, c v, ng ring rhoc tng i, t khi thnh chui, c c lc, c khng nguyn c hiu ca pha I l nhngkhng nguyn mnh to c min dch i vi bnh ho g.

- Pha IV : Tng ng vi khun lc dng R, vi khun hnh si t o hn v hay xpthnh chui ngn, khng c v, khng c c lc, mt khng nguyn pha I.

- Pha II v pha III: l nhng giai on trung gianS bin i pha c ngha quan trng trong sn xut vaccine. Mun iu ch vaccine

tt cn phi dng vi khun pha I.Trc khun ho g sn xut cc yu t lm thnh c lc v c vai tr quan trng trong

c ch bnh sinh:- c t ho g: bn cht protein, do vi khun pha I tit ra, lm tng lng AMP vng

dn n s tng tit dch v cht nhy ng h hp (triu chng c trng ca cn ho trongbnh ho g). Khng th khng c t ho g c vai tr bo v chng nhim trng.

- c t Adenylate cyclase: c th xm nhp vo t bo ng h hp lm tng titAMP vng, c ch hin tng ho hng ng bch cu a nhn trung tnh v c ch hintng thc bo. c t ny c vai tr bo v vi khun trong giai on sm ca bnh.

- c t t bo kh qun (tracheal cytotoxin): gy tn thng c hiu cc t bo lngchuyn ca biu m ng h hp.

- c t khng chu nhit v ni c t (lipopolysaccharid): vai tr sinh bnh khngr.

- Khng nguyn thn: chu nhit, cn gi l ngng kt nguyn, khng nguyn nychung cho c gingBordetella.2. Kh nng gy bnh ngi B. pertussis gy bnh ho g, thng gp tr em, rt d ly v gy thnh dch.

Bnh ho g ly trc tip qua ng h hp, ly nht thi k u ca bnh. Vi khunpht trin lin bo ng h hp, khng vo mu. Vi khun gii phng cc c t gy

thng tn ng h hp v gy nn cc du hiu ton thn ca bnh ho g.Bnh ho g l mt bnh nhim khun cp tnh ng h hp, lm vim long ngh hp v xut hin nhng cn ho c bit, gy nhng bin chng phi v no, nh hng tis pht trin tr tu ca tr, nht l tr s sinh.

Bnh ho g xy ra quanh nm, thng gp tr mi n 5 tui. T vong nhiu nhtl tr em di 1 tui. Bnh c th gp ngi ln v ch gy ho dai dng khng thnh cnr rt. Ngy nay, nh c vaccine tt t l mc bnh ho g gim rt nhiu.3. Chn on vi sinh vt3.1. Chn on trc tip

- Ch yu l phn lp vi khun. C nhiu cch ly bnh phm, tt nht l ly bnhphm thi k u ca bnh. Ly bnh phm hng mi bng tm bng mm v n hi qua

ng mi, cy vo mi trng Bordet-Gengou ngay ti ging bnh nhn. C th dng mtda mi trng m ra v cch ming bnh nhn 10cm hng nc bt bn ra trong cn ho

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khng kch thch khong 15 giy. t m 370C/ 2-3 ngy. Xc nh khun lc in hnh,nhum gram xc nh hnh th vi khun v lm phn ng ngng kt vi khng huyt thanhc hiu.

Ngoi ra, c th dng khng th n dng tm c t ho g trong bnh phm, dngk thut khuch i gen (PCR: Polymerase Chain Reaction) tm on ADN c hiu ca vi

khun.3.2. Chn on gin tipTm khng th khng c t ho g trong huyt thanh bnh nhn.

4. Phng bnh v iu tr4.1. Phng bnh4.1.1. Phng bnh khng c hiu:

Pht hin bnh sm v cha tr kp thi, cch ly bnh nhn v hn ch tip xc nht lnhng bnh nhn ang thi k u ca bnh.4.1.2. Phng bnh c hiu

Vaccine ho g hin nay l vaccine cht, c lm t vi khun ho g pha I. Dngvaccine ho g tim ng lot cho tr em di 1 tui gy min dch c bn. Tim nhc li

sau 1 nm cng c min dch v sau 5 nm tim nhc li mt ln na. Vaccine phng bnhho g l mt trong 6 loi vaccine bt buc trong chng trnh tim chng m rng, thngdng di dng 1 vaccine hn hp Bch hu-Un vn-Ho g (DTC: Diphterie-Tetanie-Cough). Ngoi ra c th dng huyt thanh min dch hoc globulin min dch ngi phng

bnh v cha bnh ho g tr cn b.4.2. iu tr

Phi pht hin sm cch ly v iu tr ngay bng khng sinh. Liu php khng sinhkhng rt ngn c giai on kch pht nhng loi tr c vi khun gy bnh, gim lylan, d phng bi nhim. Khng sinh chn lc l erythromycin.

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TRC KHUN M XANHV BURKHOLDERIA PSEUDOMALLEI

Mc tiu hc tp1.Trnh by c c im sinh vt hc ca trc khun m xanh v Burkholderiapseudomallei

2.Trnh by c kh nng gy bnh ca hai vi khun ny

3.Trnh by c phng php chn on sinh vt hc, phng php phng nga v iu tr

Trc khun m xanh v Burkholderia pseudomallei thuc h Pseudomonadaceae , hny bao gm nhng trc khun Gram (-), hiu kh, di ng bng mt hoc nhiu lng mtu (trBurkholderia mallei khng di ng), chng chuyn ha nng lng bng hnh thcoxy ha carbohydrate, khng ln men cc loi ng. C enzyme oxydase v enzymecatalase. Chng phn b rng ri trong thin nhin, ch mt s loi c kh nng gy bnh

ngi, ng vt hoc thc vt.I. TRC KHUN M XANH (Pseudomonas aeruginosa)

Pseudomonas aeruginosa thng tm thy trong t, trong nc hoc trn c th ngiv ng vt. Trc khun m xanh l tc nhn chnh ca nhim trng bnh vin v cc nhimtrng c hi.

1. c im sinh vt hc

1.1. Hnh th

Trc khun Gram m, kch thc thay i thng thng nh v mnh,1,5 - 3 m, thng hp thnh i v chui ngn, rt di ng, c lng mt u, him khi to

v v khng to nha bo.

1.2. Nui cy

Vi khun hiu kh, mc d dng trn cc mi trng nui cy thng thng nh thchdinh dng, thch mu, canh thang. Nhit thch hp 30 - 37 0C, nhng c th pht trinc 410C. pH thch hp l 7,2-7,5. Khun lc thng ln, trong, b u hoc khng u,c th c nh kim loi, mu xm nht trn nn mi trng mu hi xanh, mi thm. Cng cth gp loi khun lc x x hoc nhy.

Tnh cht c trng ca trc khun m xanh l sinh sc t v cht thm. Trn mitrng nui cy c pepton, vi khun c th tit ra cc loi sc t sau :

-Pyocyanin: l loi sc t phenazin c mu xanh l, tan trong nc v chlorofoc, khuchtn ra mi trng nui cy lm cho mi trng v khun lc c mu xanh. Sc t ny sinh rathun li trong mi trng tip xc nhiu vi khng kh. Ch c trc khun m xanh sinh sct pyocyanin.

-Pyoverdin: l loi sc t hunh quang, pht mu xanh khi chiu tia cc tm c bcsng 400 nm, tan trong nc nhng khng tan trong chlorofoc. Ngoi trc khun m xanhcn c mt s loiPseudomonas khc to thnh sc t ny.

-Pyorubrin: sc t mu hng nht, ch 1% s chng trc khun m xanh sinh ra sc tny.

-Pyomelanin: sc t mu nu en, ch 1-2% s chng trc khun m xanh sinh sc tny.

C khong 5-10% s chng trc khun m xanh khng sinh sc t.

1.3. Tnh cht sinh ho

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Trc khun m xanh c oxydase dng tnh(+), lm lng gelatin, kh NO3 thnh N2. Sdng carbohydrat theo li oxy ho c sinh axit nh glucose, mannitol, glycerol,arabinose...Lactose m tnh (-), Citrat simmon dng tnh(+), ADH dng tnh(+) ; Ureasem tnh(-), indol m tnh(-), H2S m tnh(-).

1.4. Khng nguyn

Vi khun c khng nguyn lng H khng bn vi nhit v khng nguyn O chu nhit.Da vo khng nguyn O, ti nay ngi ta chia trc khun m xanh lm 16 typ huyt thanh.Cng c th nh typ phage nhng thng nh typ bacterioxin (pyocin) trong cc v dch.

Cng nh cc trc khun ng rut, khng nguyn O ca trc khun m xanh mangni c t bn cht gluxit-lipit- protein. Nhng trong c ch sinh bnh quan trng hn lngoi c t. Trong 3 loi ngoi c t do vi khun to thnh ngoi c t A c xem nh lnhn t ch yu v c lc, n khng bn vi nhit, git cht chut nht, chut ln v cn trs tng hp protein tng t nh c t bch hu.

2. Kh nng gy bnh

Trc khun m xanh l loi vi khun gy bnh c iu kin. V vy him gp nhim

trngPseudomonas aeruginosa ngi bnh thng tr nhim trng th pht nh vim taingoi mn. Nhim trng thng xy ra nhng ngi m c ch bo v b tn thng nh sdng corticoid hoc khng sinh di ngy, bng nng hoc tim tnh mch ma ty... V trnhim trng thng thng l ng tiu v vt thng h (nht l vt bng). Ti ch xmnhp chng gy vim c m (m c mu xanh), c th suy gim sc khng chng c thxm nhp vo su hn trong c th v gy vim cc ph tng nh cc nhim trng nung mv nhng p xe nhng phn khc nhau c th ngi. Nhng trng hp vim mng trongtim, vim phi, vim mng no tuy him nhng cng xy ra hoc gy bnh ton thn (nhnhim khun huyt, nhim khun tr mi hoc non thng bnh rt trm trng).

Nhim khun mu thng gy cht xy ra ngi suy nhc.

Nhng nm gn y nhim trng trc khun m xanh tr nn quan trng do :iu trv phng nga nhng nhim trng khc bng nhng khng sinh m n khng, s dng ccthuc corticoit, thuc chng chuyn ho v thuc gim min dch lm cho gim st sc khng ca c th, s dng cc dng c thm khm nh ng thng v cc dng c khc thm d cha c kh khun tt, s dng ngy cng rng ri mu v cc sn phm ca mum ta khng th kh khun c trong khi cc cht ny c th b nhim Pseudomonas. Trckhun m xanh l mt tc nhn nhim trng bnh vin ng lu : nhim trng sau m v

bng nng. Nhim trng trc khun m xanh trong nhng trng hp c th gy cht. Tl t vong do nhim trng mu c th vt qu 80%.

3. Sinh l bnh hc

Mt s tc gi chng minh rng trc khun m xanh gy bnh c l do:

- Mt c t to thnh t mt hn hp cht c gm: dung huyt t, protease, lexitinase.

- Khng nguyn nhy xung quanh vi khun gm mt ADN gn vi gluxit- lipit -prtein ca khng nguyn O (ni c t) ca vi khun. Khng nguyn ng vai tr quan trngtrong c lc ca vi khun (c th so snh vi vai tr ca ni c t).

4. Chn on

Bnh phm l m ca cc vt thng b bi nhim, cht dch ph qun, nc tiu, dichmng phi... Trong chn on dch t hc: dch chuyn, dch ra vt thng, dng c ngoikhoa... l mu nghim.

Mu nghim c cy ln mi trng thng thng nh thch dinh dng hoc mi

trng c cht c ch nh mi trng Cetrimide. 370

C trong kh trng thng.

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Chn khun lc dt, ln, b khng u, b mt c nh kim loi, to sc t ha tannhum xanh khun lc v nhum xanh mi trng xung quanh khun lc. Xc nh vi khunda vo trc khun Gram (-), khng sinh nha bo, oxidase (+), chuyn ho ng theo kiuoxy ho, c bit khun lc c mi thm v sinh sc t nhum mu mi trng xung quanhkhun lc. i vi cc chng khng sinh sc t cn cy vo cc mi trng tng sinh sc t

nh: King A (tng sinh pyocyanin) v King B (tng sinh pyoverdins). Ngi ta c th s dngnhng k thut khc nhau xc nh c ngun gc ca cc chng trc khun m xanhtrong cc nhim trng bnh vin.

5. Phng nga v iu tr

Nhim trng do Pseudomonas aeruginosa kh iu tr v khng vi nhiu khngsinh. Nhng chng thng gp cho thy vi khun thng khng vi 3 khng sinh hoc hn.Trong iu tr phi lm khng sinh . Hin nay thng s dng tobramycin, amikacin,carbenicillin, cefaperazon, ceftazidim. Gn y min dch liu php hot ng v th ngc s dng bnh nhn bng vi kt qu kh tt. Nhim trng ti ch c th ra vi 1%axt axetic hoc bi thuc m Colistin hoc Polymycin B.

II. BURKHOLDERIA PSEUDOMALLEI (Trc khun Whitmore)B. pseudomallei l tc nhn gy ra bnh Melioidosis, mt bnh thng gp vng ng

- Nam chu . Bnh Melioidosis thng nng, t l t vong cao do chn on lm sng khkhn, bnh hay ti pht v doB. pseudomallei khng li nhiu khng sinh.

1. c im sinh vt hc

1.1. Hnh th

Trc khun Gram m ngn, bt mu thuc nhum mnh hai u, ng ring l hocchui ngn, i khi c hnh dng cu trc khun. Kch thc 0,8 x1,5 m. Vi khun di ngc mt chm lng mt u, khng sinh nha bo.

1.2. Tnh cht nui cy

Vi khun mc c cc mi trng nui cy thng thng, kh phn lp nui cyln u. Hiu kh, nhit thch hp 370C, nhng c th pht trin c t 5-420 C v mitrng c 3% NaCl.

Trn mi trng lng, vi khun mc bng cch to vng, theo thi gian vng cng dy.Trn mi trng c, to khun lc kh, b my nhn nheo, b rng ca, mu trng c hocmu kem. C th quan st thy nhiu dng khun lc c kch thc v hnh thi khc nhautrn cng mt mi trng. B. pseudomallei khng sinh sc t ho tan. Nui cy to ra mithm (ging mi nho).

1.3. Tnh cht sinh ho

Oxydase dng tnh(+), catalase dng tnh(+). S dng carbohydrat theo li oxy ho

sinh axit nh: arabinose, dulcitol, glucose, lactose v mannitol, lm lng gelatin, ADH(arginin ihydrolase) dng tnh(+), citrat simmon dng tnh(+), indol m tnh(-), kh nitratthnh N2 , di ng mnh.

1.4. Sc khng

B. pseudomallei c mt trong t nhin, c bit c tm thy trong cc cnh ng lanc vng ng Nam . Chng sng hng tun n hng thng ni m nu gp iu kinthch hp nh khng c nh sng mt tri v lnh.

1.5. Min dch

Do vi khun phn b rng ri trn ng rung, 30-50% nng dn kho mnh sng trongvngB. pseudomallei lu hnh c khng th chng vi khun ny. Khi b bnh, khng th tngcao v cn tn ti vi thng sau khi khi bnh. Tuy nhin, khng th ny khng c vai tr bov, bnh nhn c th b ti nhim hoc ti pht mt cch d dng.

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2. Kh nng gy bnh

2.1. ngi

Vi khun gy bnh Mlioidosis thng gp Min in, Thi Lan, Vit Nam, Lo,Campuchia, Indonesia v chu c.

Vi khun xm nhp vo c th ch yu qua vt thng, nhng ch sy st trn da. Tini xm nhp chng hnh thnh nhng mn m nh, c khi to thnh mt p xe rt ln. nhng ngi suy gim min dch, mc cc bnh mn tnh ko di vi khun thng vo mu vgy ra bnh cnh lm sng nng ca mt nhim khun huyt. T mu vi khun n cc phtng gy nn p xe nh nhiu c quan nh phi, thn, gan, lch. Sau cc p xe nh tothnh cc p xe ln gy ra cc triu chng lm sng nhiu c quan khc nhau. Vi khun cth sng trong cc i thc bo, iu ny c th gii thch nhng trng hp bnh ti pht.Bnh c th din bin cp tnh, bn cp v mn tnh

- Th cp tnh nhim khun huyt vi a chy v st c tnh, thng cht trong vi ngy.

- Th ban cp dng thng hn vi p xe phi, thn, gan, c, cht sau vi tun l.

- Th mn tnh c th khu tr (p xe xng hoc da) hoc nhim khun huyt kiuln sng.2.2. Kh nng gy bnh thc nghim

Ngi ta c th gy bnh c cho phn ln cc ng vt nh th, chut lang, chutnht, nga bng nhiu ng khc nhau: qua da, tim tnh mch, tim phc mc hoc ngh hp. Bnh melioidose sc vt c th ly sang ngi.


3.1. Phn lp vi khun

Bnh phm l m p xe, mn m, mu trong nhim khun huyt, m trong vim phqun, dch mng phi, dch mng tim...Cy bnh phm vo mi trng nui cy thng thng

nh thch thng, thch mu, canh thang hoc mi trng chn lc c cha gentamicin. Xcnh vi khun da vo hnh th, tnh cht bt mu, hnh thi khun lc v tnh cht sinh ha.

3.2. Chn on huyt thanh

- Trong iu tra dch t hc: dng phn ng ngng kt hng cu th ng tm khng thngng kt

- Trong chn on bnh: dng phn ng ngng kt hng cu th ng v ELISA vikhng nguyn protein

4. Phng nga v iu tr

4.1. Phng bnh

Hin nay cha c vaccine. Tng cng sc khng chung, gi gn v sinh, trnh cc

tn thng da trong khi lm vic ni c vi khun.4.2. iu tr

Dng khng sinh nh tetracyclin, chloramphenicol, bactrim, ceftazidim. V vi khun lntrnh trong t bo nn cn lu chn la khng sinh khuch tn tt vo trong t bo v dngtrong thi gian di phng nga ti pht. Vi khun khng gentamycin, ampicillin,

polymycin. Dng bin php chc ht m p xe, tng cng sc khng, iu tr triuchng.

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- Khng nguyn lng H: Khng c gi tr trong thc tin.

- Khng nguyn c t rut bn cht l protein, c t rut ca V.cholerae 01 kchthch c th sinh khng c t.

1.5. Sc khng

Vi khun t cht nhit 100oC hoc 80oC/5 pht v b tiu dit bi cc ha chtnh cloramin, cresyl, vi cc ... Kh hanh v nh nng mt tri cng lm vi khun d cht.Trong nc , nc bin, nc ao h vi khun sng c vi ngy.

2. Kh nng gy bnh

2.1. Sinh bnh hc

Cc vi khun t xm nhp c th bng ng tiu ha, chng phi vt qua hng rodch v ca d dy c pH axt xung rut non l ni c pH thch hp cho s pht trin cavi khun. axt bnh thng ca dch v l mt cn tr rt ln i vi qu trnh sinh bnhca vi khun t. Vo n rut non, V.cholerae bm dnh vo t bo nim mc rut nh c ccyu t bm dnh nh khng nguyn TCP, khng nguyn ngng kt hng cu nhy cm vimannoza..., vi khun nhn ln v tit ra c t rut. Cc vi khun khng xm nhp vo trongcc t bo nim mc rut.

c t rut ca vi khun t l mt protein gm 2 tiu phn A (Active) v B (Binding)c chc nng ring bit. Tiu phn A c hai tiu n v A1 v A2, tiu phn B c 5 tiu n vB1, B2, B3, B4 v B5. Tiu phn B c chc nng gn c t rut vo th th ganglioside GM1 trn mng ca t bo nim mc rut, cn tiu phn A m ch yu l A1 xm nhp vo bntrong t bo hot ha enzymee adenylate cyclase, lm tng nng AMP vng ni bo lmcho t bo nim mc rut gim hp thu Na+, tng tit nc v Cl-, gy ra a chy cp tnh. Nukhng c iu tr tch cc bnh nhn s cht v kit nc v mt cc cht in gii.

c t t cn gy nn c ch min dch t bo bng cch tc ng trc tip lnmacrophage v t bo lympho T.

Trong qu trnh sinh bnh t, c t t v vi khun t khng gy nn thng tn nimmc rut. V vy c ch hp th li mui, nc v glucose vn nguyn vn. y l c s sinhl cho vic b dch bng ng ung dung dch c in gii v glucose (ORESOL) c tcdng tt (glucose y nhm to iu kin hp th li Na cao hn, ch khng phi l cungcp nng lng).

2.2. Kh nng gy bnh

Trong iu kin t nhin bnh thng, V.cholerae ch gy bnh t cho ngi. Bnh tl mt bnh nhim trng nhim c cp tnh, ly rt mnh gy thnh dch ln. Thi gian

bnh t 2 n 5 ngy. Du hiu c trng ca thi k ton pht ca bnh l tiu chy v nn,phn lng v trng nh nc vo go. Bnh nhn mt nc, mt mui rt nhanh, c th mt 1

lt nc trong 1 gi do ch vi gi l xut hin hi chng mt nc cp tnh lm cho tonthn st i rt nhanh v rt nng. Nu khng c iu tr, t l cht rt cao (50 n 60%).

Lm sng bnh t c nhiu biu hin rt khc nhau t th nh d b qua cho n thnng vi hi chng t in hnh.

2.3. Min dch

p ng min dch dch th trong bnh t lm xut hin IgG trong mu v IgA tit nim mc rut. Cc khng th ny chng li vch t bo vi khun, ngn cn vi khun bmdnh vo nim mc v chng li c t t, ngn cn c t t (tiu phn B) gn vo mng t

bo nim mc rut.

2.4. Dch t hc

Bnh t ly truyn qua ng tiu ha qua thc n, nc b nhim khun. Nguntruyn nhim l ngi bnh v ngi lnh mang vi khun t.

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K t nm 1817 cho n nay trn th gii xy ra 7 i dch t. Su i dch t udo V.cholerae sinh type c in gy nn. i dch t ln th 7 do V.cholerae sinh tp El Torgy nn, bt u t nm 1961 ko di cho n ngy nay. V.cholerae El Tor khng vi tcnhn ha hc, tn ti lu hn ngi v sng trong thin nhin lu hn V.cholerae sinh tpc in. Ngoi ra i vi vng bnh t El Tor lu hnh th nhng trng hp nng thng t

hn v nhng trng hp nh khng triu chng li nhiu hn.Bt u t nm 1992 dch t xy ra Madras v nhiu ni khc thuc n v

Bangladesh do Vibrio cholerae O139 gy nn vi c ch bnh sinh hon ton ging nhVibrio cholerae O1. Sau dch t do chng O139 ly lan ra cc nc khc.


3.1. Chn on trc tipBnh t l mt bnh cp tnh nn cy phn phn lp vi khun t l phng php

chn on tt nht.

3.1.1. Bnh phm

Ly phn sm ngay trong thi k u ca bnh trc khi iu tr khng sinh. Bnhphm phn cn a ngay v phng xt nghim trong vng 2 gi. Nu gi bnh phm i xaphi cho vo mi trng bo qun v vn chuyn Cary Blair, v a v phng xt nghimcng sm cng tt.

3.1.2. Xt nghim knh hin vi

Soi ti c th thy vi khun t di ng rt nhanh. Nhum Gram thy nhiu phykhun Gram m. Xt nghim bnh phm knh hin vi c tc dng chn on s b.

3.1.3. Nui cy

Bnh phm c cy vo cc mi trng chn lc v mi trng phong ph phnlp vi khun. Xc nh tnh cht sinh vt ha hc. Lm phn ng ngng kt trn phin knhvi khng huyt thanh a gi O1 v vi khng huyt thanh n gi c hiu tp Inaba hocOgawa xc nh chn on.

3.1.4. Phng php chn on nhanh

xc nh nhanh vi khun t c th dng cc k thut nh bt ng vi khun, khngth hunh quang trc tip.

3.2. Chn on gin tip

Phng php chn on huyt thanh khng gip ch cho chn on bnh. N c thc dng trong iu tra dch t hc.


4.1. Phng bnh

4.1.1. Phng bnh chung- Gim st dch t hc, ch ng pht hin ngun bnh sm, kp thi cch ly, bao vy

v x l.

- Lm sch mi trng sng bng cc bin php nh x l rc v nc thi theo ngyu cu v sinh; kim tra v sinh thc phm; thc hin n chn ung si v sch ...

4.1.2. Phng bnh c hiu

- Vaccine cht, dng ng tim trong da, c hiu lc thp v thi gian bo v ngn.Hin nay nhiu nc khng s dng loi vaccine c in ny.

- Vaccine sng gim c lc: to ra cc chng t bin khng c lm vaccine

ung. Hin nay ang th nghim.

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- Vaccine cht, ung: Loi vaccine ny c th dng ton t bo bt hot n thunhoc dng kt hp vi tiu n v B ca c t t c tinh ch.

Vit Nam dng loi vaccine t ng ung n lin cha cc t bo Vibrio choleraeO1 c in v El Tor c bt hot bng nhit v formalin. Hin nay ang th nghim loivaccine t bt hot (Vaccine biv-WC) gm c Vibrio cholerae O1 v Vibrio cholerae O139.

4.2. Cha bnhPhi b nc v in gii sm, nhanh v cho bnh nhn. Dng khng sinh

Tetracycline, Doxycycline ...

II. VIBRIO PARAHAEMOLYTICUSV.parahaemolyticus c phn lp ln u Nht Bn nm 1950 t phn bnh

nhn tiu chy do n c bin.

1. c im sinh vt hc

V.parahaemolyticus c hnh hi cong v ngn. Gram m v di ng.

L vi khun a mn (halophile) tn ti trong nc bin v cc ng vt bin

nh c, tm, s, c ...Vi khun mc tt mi trng kim v mn. Nhit thch hp cho s nhn

ln l 37oC.

V.parahaemolyticus c oxidase dng tnh, ln men D-mannitol, maltose,L.arabinose, khng ln men saccharose.

V.parahaemolyticus b cht 65oC sau 10 pht, chng khng pht trin c nhit di 15oC.

Vi khun c 3 loi khng nguyn :

+ Khng nguyn thn 0 : chu nhit, c chia thnh 12 type.

+ Khng nguyn lng H.

+ Khng nguyn v K : khng chu nhit, c chia thnh 59 type.

2. Kh nng gy bnh

V.parahaemolyticus l mt trong nhng nguyn nhn gy nhim trng nhimc thc n. Ngi mc bnh ch yu l do n phi thc n hi sn cha c nuchn hoc b nhim khun trong qu trnh ch bin v bo qun.

Thi gian bnh bnh ngn t 2 - 6 gi. Bnh biu hin cc triu chng nnv tiu chy kiu t nh hoc tiu chy kiu l trc khun.

Bnh do vi khun ny gy ra gp nhiu nht Nht Bn, ngoi ra cn gp nhiu nc khc. Vit Nam gp nhiu ln ti vng b bin Bc B.

3. Chn on vi sinh vt- Phn lp vi khun t bnh phm l phn, cht nn ca bnh nhn.

- Phn lp vi khun t cc hi sn trong trng hp iu tra thc phm nhimkhun.


- Cha c vaccine phng bnh.

- Phng bnh chung bng cch nu k thc n hi sn, khng n sng hi sn.

- iu tr bng cc khng sinh nhy cm nh tetracycline, chloramphenicol ...

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CAMPYLOBACTER V HELICOBACTER

Mc tiu hc tp1. Trnh by c mt s tnh cht vi khun hc ca Campylobacter v Helicobacter.2. Nu c kh nng gy bnh ca cc vi khun ny.3. Trnh by c mt s phng php chn on vi khun hc i vi Campylobacter v

Helicobacter.

I. CAMPYLOBACTER JEJUNIGing Campylobacterthuc h Spirillaceae, gm c cc loi khc nhau c th

gy bnh cho ngi.1. c im sinh vt hc

Campylobacter jejuni l nhng vi khun b, mnh, Gram m, hnh du phynhn hai u, rt di ng nh c 1 lng 1 u, khng sinh nha bo. Nui cyC.jejuni trn mi trng nhn to thng kh khn v vi khun i hi iu kin vi

hiu kh (micro-aerophile). Mc c 37o

C nhng mc tt hn 42o

C, khng mc 25 oC. Thng dng cc mi trng chn lc nh thch mu Columbia, thch mutryptose phn lp vi khun. C.jejuni mc chm sau 2 - 3 ngy.

Vi khun c Oxydase v Catalase, phn hy nitrat, khng oxy ha hoc khngln men cc loi ng.

C.jejuni c khng nguyn O chu nhit c chia thnh 23 typ huyt thanh vc khng nguyn H khng chu nhit.2. Kh nng gy bnh

C.jejuni l mt tc nhn gy vim rut cp tnh thng gp ngi. Chng xm nhpvo ngi do n ung cc thc n v nc b nhim khun, do tip xc vi ng vt, ch yul vi gia cm, gia sc.

Thi gian bnh 2-10 ngy. Th lm sng thng gp l bnh cnh ca mtvim rut cp tnh vi du hiu au bng, tiu chy d di, phn nc c khi c muv m. C trng hp xy ra nhim khun huyt. Tiu chy do C.jejuni ko di 5-10ngy. a s trng hp khi khng cn iu tr bng khng sinh.

C ch gy bnh cha r. C.jejuni c c t rut, nhng c kin cho rng vikhun ny c kh nng xm nhp ging nh Shigella. C.jejuni nhn ln ch yu hitrng v hng trng.

Bnh vim rut do C.jejuni xy ra nhiu ni trn th gii, gy tiu chy cp ngi,c bit tr em v khch du lch t cc nc pht trin n cc nc nhit i.3. Chn on vi sinh vt

Chn on vim rut cp do C.jejuni phi da ch yu vo phn lp vi khun t phn

ca bnh nhn. Cy phn vo cc mi trng chn lc, nhit 42 oC t 2 - 3 ngy trongkh trng c 5% oxy, 10% cacbonic v 85% nit.4. Phng bnh v iu tr

Cha c vaccin. Cn ch v sinh mi trng, v sinh n ung. Khng sinh ch nndng trong nhng trng hp nhim khun huyt hoc tiu chy ko di.II. HELICOBACTER PYLORI

T nm 1900 n nm 1980, thnh thong ngi ta ghi nhn c s hin din ca mtvi khun hnh xon nim mc d dy. Nhng nhng pht hin khng c quan tmng mc, bi v cho n cui th k 20 ny, hu nh ngi ta vn quan nim rng d dy lmi trng khng c vi khun do pH acid ca n. Mi n nm 1979, Warren a ra githuyt chnh vi khun l cn nguyn gy ra vim, lot d dy - t trng. Nm 1981,Marshall bt u tm ra phng php phn lp vi khun ny, n nm 1982 ng nui cythnh cng v thy vi khun ny ging nh Campylobacter jejuni , nm 1983 ng chnh thc

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cng b vi khun ny trn tp ch Lancet (Paris) vi tn l Campylobacter pyloridis, v sauc gi l

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