Lecture 21 Vibrio cholerae

بسم الله الرحمن الرحيم

FAMILY: VIBRIONACEAE

Prof. Khalifa Sifaw Ghenghesh

3 Important Genera:

• Vibrio

• Aeromonas,

• Plesiomonas

• Oxidase +ve

Habitat:

بسم الله الرحمن الرحيمVibrio cholerae

I. V. cholera O1: •Agglutinate in Antisera Directed

Against O1 Antigen.•Produce Enterotoxin.

2. Non-Toxigenic V. cholera O1:

3. Non O1 V. cholera (NCV, NAV):

II. V. cholerae O139

Vibrio choleraeGram-negative, curved rods

Vibrio cholerae Leifson flagella stain

Vibrio choleraecurved rods with polar flagellum (EM)

V. cholerae O1---------------------------------------------------

Biotye

El-torClassic

Haemolysis (SRBC) + --

VP + --

Resistance to PB + -----------------------------------------------------

VIRULENCE FACTORS:• Enterotoxin: CT• Adherence: Ability to Attach to the

Microvilli at the Brush Borders of the Epithelial Cells.

EPIDEMIOLOGY:• Causes Widespread Disease.• Human Carriers: • Modern International Travel:

PATHOGENESIS & CLINICAL INFECTION:• Infectious Dose:• Incubation period:• Abrupt Onset of Diarrhoea & Vomiting• Stool > Watery (Rice Water), Odorless• Fatality Rate:

LAB. DIAGNOSIS:• Isolation & Identification of the

Organism.• Media: TCBS• Transport Media:

TREATMENT: • Prompt Replacement of Fluid &

Elecrolytes• Tetracycline and others

PREVENTION & CONTROL:• Adequate Sewage Treatment and

Water Purification Systems.• Vaccination: ??

Typical Vibrio cholera contaminated water supply

Vibrio parahaemolyticus

• Halophilic vibrio• Associated with seafood• Gastroenteritis:

– Outbreaks of Food Poisoning

• Extraintestinal infections > wounds• Virulence Factors:

– Haemolysin > – heat-stable cytotoxin– Heat-labile enterotoxin– Adherence to human intestinal cells

Aeromonas species

A. hydrophila, A. sobria & A. caviae• Enterotoxins, Cytotoxins, Haemolysins,

Etc…• Gastroenteritis, Septicaemia, and Skin

& Wound Infections TREATMENT

• TMP-SMX, Tetracycline, Gentamicin • Resistant to -Lactam Antibiotics.