Antiseptic Techniques

8/2/2019 Antiseptic Techniques

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ANTISEPTIC TECHNIQUES

BY

DR. SB ZAILANISENIOR LECTURER/CONSULTANT

DEPARTMENT OF MEDICAL MICROBIOLOGYCOLLEGE OF MEDICAL SCIENCES

UNIVERSITY OF MAIDUGURI

DATE: SEPTEMBER, 2008


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TERMINOLOGY

Sterility Total absence of viable microorganisms as assessed

by no growth on any medium.

Bacteriocidal Kills bacteria

Bacteriostatic Inhibits growth of bacteria

Sterilization The use of physical and/or chemical procedures

to completely eliminate or destroy all forms of microbial life. This

term while absolute, is relative to our ability to detect

microorganisms.


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Disinfection a process that reduces or completely eliminate

spores. An object that has been properly disinfected could

theoretically transmit- producing organism, but the possibility is

greatly reduced.

Germicide- a substance that destroys microorganism, especially

pathogenic microorganisms. Technically a germicide does not

destroy, spores. However, the term may be used commonly to

refer to substances with sporicidal activity. It applies to agents

used both on living tissue and on inanimate objects.

Antiseptic a substance that inhibit or destroys microorganisms.

No sporicidal action is implied. The term is used specifically for

substances applied topically to living tissue.


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CHEMICAL DISINGECTANTS/STERILANTS

1. Alcohols are protein denaturants that rapidly kill vegetative

bacteria when applied as aqueous solutions in the range of 70-95%

alcohol They are inactive against bad spores and many viruses.

* Ethanol (70-90% and isoproprpyl (90-95%) alcohol are widely

used as skin disinfectant before simple invasive procedures

such as venipuncture.

2. Phenolics They act by coagulating proteins. Phenol itself is not

used as a disinfectant because of its toxicity, carcinogenicity, and

corrosiveness. Clear soluble phenolic disinfectant such as clearsol,

hycolin, or stericol are resistant to inactivation by organic matter and

are active against a wide range of Gram positive and gram negative

bacteria.


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* Phenotics are reasonable effective against mycobacterium but

have little activity against endospores, and Viruses.

* Their activity reduce by alkaline pH.

3. Aldehyde:

* Gluteraldehyde is a relatively powerful agent that is

considered a high level disinfectant and a sterilant when used

appropriately.

* They usually supplied at the working conc. of 2%. Their ability

to penetrate organic material is poor.

* It is usually used for the sterilization of objects not suitable for

autoclaving e.g plastic prosthesis, thermometers, anaestetic

equipment and endoscopes.


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* Iterms for steriliazation requires 3 hours immersion, for

disinfection 15min is sufficient.

- Formalin is a 40% solution of formaldehyde in water when

diluted to 10%, it remains a true sterilizing agent and is lethal to

bacteria, viruses, fungi and spores.

* It is slow in action and may require up to 24 hours to achieve itmaximum affect.

4. Halogens- This group consist of bromine, chlorine, fluorine and

iodine. Only iodine and chlorine, however, are commonly used fordisinfection.

* Halogens kill vegetative bacteria, fungi, viruses but not tubercle

bacilli or endospores.


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* Iodine is used chiefly for skin. Chlorine combine with water toform Hcl which is bacteriocidal.

* Chlorine is highly effective oxidizing agent. In conc. Less thanone part per million, chlorine is lethal within seconds to mostvegetative bacteria and it inactivate most viruses.

* Iodine is an effective disinfectant that acts by oxidizing

essential component of microbial cell.

* It is commonly used as tincture of 2% iodine in 50% alcohol. Itkills more rapidly than alcohol or iodine alone.

* Other preparations are available in which iodine is combinedwith organic compounds such as detergent in dissociablecomplex to form iodophors.


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5. Quaternary Ammonium Compounds

* Cationic detergent, particularly quaternary ammonium

compounds (quats) such as benzalkonium chloride, are highly

bacteriocidal.

* Their hydrophobic and lipophilic groups react with lipid of the

cell membrane of the bacteria, alter it surface properties and it

permeability .

* These compounds have little toxicity to skin and mucous

membranes, and thus have been used widely in conc. of 0.1%

for their antibacterial effects. They are inactive against spores

and most viruses.


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6. Peroxygen Compounds

* Included among the perioxygen compounds are the

disinfectants hydrogen peroxide and peracetic acid.

* Both compounds are bacteriocidal, virucidal, sporucidal and

fungicidal, but the activities against mycobacteria are not well

documented.

7. Ethylene oxide Is an inflammable and potentially explosive gas. Itis an alkylating agent that inactivate microorganisms by replacing

labile hydrogen atoms on hydroxyl, carboxy or sulfohydryl groups.

* Ethylene oxide sterilization resemble autoclaves, expose to10% ethylene oxide or CO2 at 50oc for 4-6hrs and must be

followed by prolonged period of aeration to allow the gas to

diffuse out.


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* Ethylene oxide is an effective sterilizing agent for heat labile

devices such as prosthesis.

8. Plasma gas- Plasma gas sterilization gas recently bee applied to

the treatment of medical devices.

* In this process, H2O2 is injected into the sterilization chamber

and vaporized. The vapor diffuses through the chamber and

radio frequency energy is applied to the chamber to create gasplasma.

* The free radicals formed in the plasma gas are involved in

microbial inactivation.

* The process temperature does not exceed 40oC.


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ANTISEPTICS

Antiseptics are found in the lab. Primarily in products used for hand

washing. The necessity for hand washing is based on the fact that

the hands become contaminated with pathogenic microorganismsduring lab. Procedures

Whether the product used for hand washing in the laboratory needs

to contain an antimicrobial agent has never been shown by any well-controlled studies.

The proper technique involves a rigorous rubbing together of all

surfaces of well-lathered hands for 10-15 see followed by rinsingunder a stream of water. Particular attention should be paid to

areas under the finger nails and around the cuticles.


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Some of the same chemicals found in disinfectants are also found in

and hand washing preparations. However, a hand- washing

product should not be used as disinfectant, and a disinfectant should

not be used for hand- washing.

Common chemicals found in hand washing products are:-

Alcohol

Chlorhexidine gluconate,

Iodophors

Chloroxylenol

Triclosan


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Alcohols are very fast acting and effective against a broad

spectrum of microorganism, including mycobacteria, fungi, and

viruses. They are safe and inexpensive. Isopropyl and ethyl

alcohols are used. They have tendency to dry the skin.

Chlorhexidine gluconate is a broad spectrum (CHG) antiseptic

with good activity against gram positive and negative bacteria, but

poorer activity against viruses, mycobacteria and fungi.

* This antiseptic is generally used in a conc. Range of 2-4%.

* Chlorhexidine gluconate activity is affected by hard water,

lotion and soap.


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Iodophors while having good activity against both gram positive

and gram negative bact. Fungi, mycobacteria and viruses, have the

disadvantage of staining and causing irritation. They are generally

available in conc. of 0.7% available iodine.

Chloroxylend has good antiseptic activity but may not be as active

as chlohexidine and iodophors. It is used in conc. ranging 1.5-3.5%.

Triclosan is commonly used in deodorant soaps. It is active

against both gram positive nod gram negative organisms with the

exception of pseudomonas spp. It activity against other organisms

is not as good. It is generally used in a conc. range of 0.3 1.0%.


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. Other chemical for hand washing include, hexachlorophene and

benzalkonium chloride.

The type(s) of hand-washing agent to be used needs to be well

thought out.

Three key factors to be considered are:-

1.The type of microorganism

2.The acceptance of the agent b the personnel

3.The cost.

ANTISEPSIS

Most nosocomial infection (NI) are believed to be transmitted by thehands of health care workers. Many NI can be prevented by using

hand-washing to interrupt the transmission of the pathogens on the

hands.


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. Despite the simplicity and effectiveness of hand washing (HW),

several studies have documented poor compliance with

recommendations concerning HW.

Improvement in the frequency of HW have resulted in decreased

infection rates in intersive care units.

Other data suggest that NI rates are reduced by the use of antiseptic

HW.

NO single antiseptic agent is ideal for use in all situations.


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CONTROL MEASURES

* HW

For general patient care, a plain non antimicrobial soap in any

convenient form (bar, leaflet, powder, or liquid) is acceptable. If bar

soap is used, the hospital should provide small bars that can be

changed frequently and soap racks that promote drainage.

Cleaning under the finger nails is a crucial part of HW, since the

majority of organisms on the hand live in the subungual region.

HW sinks should be conveniently located throughout the hospital to

facilitate frequent and appropriate HW.


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* SURGICAL HAND SCRUB

A surgical hand scrub (SHS) for approximately 5 min is performed to

remove transient flora and reduce resident floar for the duration of

surgical procedure.

Agent with good antimicrobial activity and persistence, such as CHG

or iodophors are acceptable products. An alcohol preparation yield

excellent reduction in flora. This reduction is accomplished b firstwashing the hands and arms and cleaning the finger nails

thoroughly, and then drying next, in alcohol solution.

* PREOPERATIVE PATIENT SKIN PREPARATION Antiseptics are also used for preoperative skin preparation to rapidly

decrease the number of skin flora at the operative site.


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. After the patients skin has been physically cleaned, and

antimicrobial agent that rapidly reduces the level of skin microbial

flora is applied.

Recommended agents include the alcohols, iodophors or CHG.

* PATIENT SKIN PREPARATION AT CATHETER SITE

Catheter-related bacteraemias or fungemias occur in 3-7% of central

venous catheters and 1% of arterial catheters and are most

commonly caused by skin microorganisms.

A trail that investigated whether antiseptics used to disinfect the

insertion site reduced catheter-related infection found that catheter-

related infection was higher in the 10% providone-iodine and 70%

alcohol groups than in the 2% CHG group.


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. The results suggest that use of CHG for cutanous disinfection helpsprotect against infection of central venous and arterial catheter.

* HAND LOTIONS Hand lotions are often recommended to minimize drying resulting

from frequent hand washing.

Outbreaks of bacterial infection have been caused by contaminated

hand lotions.

Concerns have also been expressed about the potential for oil-based lotion formulations (e.g petroleum jelly) to weaken latexgloves and cause increase permeability.

Hand lotions designed to protect against latex sensitivity resultingfrom glove use are now being marketed


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