7sterilization 7 2009

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Prof Dr Shamim Mumtaz THE CONTROL OF MICROBIAL GROWTH

Source of Infection : 

Source of Infection An sources of bacteria is important and in appreciation of the surgery these may be summarised as: Endogenous from the patient’s viscera (98 per cent ) and from the patient’s skin. Contamination from the air (in the operating theatre) Direct contamination, such as punctured gloves – very uncommon

Instruments : 

Instruments Cleaning is a process, which removes contamination but does not necessarily destroy microorganisms. Sterilisation results in the complete destruction or removal of all viable microorganisms including spores and viruses. Disinfection reduce the number of viable microorganisms but will not necessarily inactivate viruses and bacterial spores. Disinfectants may be classified into: High level – which is cidal to spores, bacteria & viruses. Medium – which is cidal to bacteria & viruses; Low – which is cidal to only bacteria & viruses of low resistance. Disinfection & sterilization

THE CONTROL OF MICROBIAL GROWTH : 

THE CONTROL OF MICROBIAL GROWTH Sterility Total absence of viable microorganisms as assessed by no growth on any medium . Endospores of bacteria are considered the most thermoduric of all cells so their destruction guarantees sterility Sepsis ‘== Infection Aseptic;---- Without infection

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Physical agents HEAT RADIATION FILTRATION Chemical agents Sterilization and disinfect ion is carried out with the help of;

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Used for water purification (Tyndallization) Tyndallization

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UHT 132° C/1 sec Used for milk dispensed aseptically into sterile containers, shelf life ---few months)

PHYSICAL AGENTS HEAT : 

PHYSICAL AGENTS HEAT Most important and widely used. For sterilization always consider;=== type of heat, time of application & temperature to ensure destruction of all microorganisms. Types; 1.Dry heat 2.Moist heat Mechanism of action;--- Denaturation of proteins Damaging the Membrane Enzymatic change in the microbial DNA

PHYSICAL AGENTS 1. Dry HEAT : 

PHYSICAL AGENTS 1. Dry HEAT 1. Direct flaming & Incineration: ;.---Burns & physically destroys the organisms. Used for needles , inoculating wires, all types of clinical wastes. More than 500 ° C --temperature Direct flaming

Dry heat --HOT AIR OVEN. : 

Dry heat --HOT AIR OVEN. Used for glassware, metals and objects that won't melt. 160 ° C X 2 hrs 170° C X 1 hrs

2. MOIST HEAT; AT TEMPERATURES OF ABOVE 100° C. : 

2. MOIST HEAT; AT TEMPERATURES OF ABOVE 100° C. Most frequently used method of sterilization PRINCIPLE: (Steam under pressure) Increase in pressure subjected on water increases the boiling point of steam & water Simplest autoclave Autoclaving (steaming under pressure ---- pressure cooker)

AUTOCLAVE; : 

AUTOCLAVE; An air tight chamber which steams, at a pressure of 15 Ibs / square inch, reaches a temperature of 121 ° C & is held for 15 - 20 minutes. kills even highly resistant spores FACTORS ON WHICH AUTOCLAVING DEPENDS: Temperature--- 121 ° C 2) Time (duration)----15 - 20 minutes. Pressure--- 15 Ibs / square inch cheapest and perfect method of sterilization for the objects that can withstand high temperature & pressure. heat-labile substances will be denatured or destroyed.

AT TEMPERATURES OF ABOVE 100° C : 

AT TEMPERATURES OF ABOVE 100° C Good for sterilizing almost anything Culture media, Laboratory wares Surgical instruments (needles, gauzes, dressings, theatre apparels, gloves etc ) more effective than dry air at the same temperature.

Control of sterilization (indicators of sterilization) : 

Control of sterilization (indicators of sterilization) 1.Thermocouple 2.Browne’s Tubes Change in the color of chemical indicator from red – green at the specific temperature 3.Bowie Dick – tape (Heat sensitive Tape) It has sensitive ink the color of which changes at specific temp No change in the color – poor or defective sterilization

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4. Spores of Bacillus sterothermophilus or B subtilis ;Spores are killed at 121 °C at 15 Ibs / square inch for 15 min. Paper strips impregnated with spores of above microorganism. Culture;--- No growth An absolute check of sterilization

: 

Low temperature (refrigeration and freezing) Most organisms grow very little or not at all at 0° C. Store perishable foods at low temp. to slow rate of growth and consequent food or milk spoilage Low temperatures are not cidal. Drying (Removal of water) To preserve foods like fruits, grains etc Heating 2. Evaporation 3. Freeze drying 4. Addition of salts or sugars.

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1.Gamma rays or accelerated electrons. (Industrial process) pre-packed heat sensitive articles like; Syringes, catheters and intravenous cannulas. 2. Ultra Violet light; Inhibits DNA replication Disadv; Can damage cornea & skin, therefore use in medicine is limited Used for sterilization of air & surfaces in microbiology labs (safety cabinet) & OPERATION THEATRE Sterilization by irradiation

Physical methods 3. Filtration : 

Physical methods 3. Filtration It involves the physical removal (exclusion) of all cells in a liquid or gas The most commonly used filters are;----- Nitrocellulose( pore size of 0.22 µm retains bacteria & spores) Sintered glass filters Seitz filters Swinex filters Asbestos filters

Physical methods 3. Filtration : 

Physical methods 3. Filtration Uses ;---- Important for sterilizing solutions, which are denatured by heat e.g Sterilization of solutions for I.V. use like antibiotics, injectable drugs, amino acids and vitamins. Certain media like sugars , urea solution in the lab which are denatured by heat. Sterilization of water. Air filtration – Operation Theatre.

Ultra violet light & filters used in safety cabinet & operation theatre : 

Ultra violet light & filters used in safety cabinet & operation theatre

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Alcohols Chlorhexidine Hexachlorophene Ethanol Isopropyl Alcohol Acridine Compound (Acriflavine

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Acridine Compound (Acriflavine

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Gaseous disinfectants

STERILIZATION &DISINFECTION : 

STERILIZATION &DISINFECTION Disinfectants Agents that kill microorganisms but not necessarily their spores. Not safe for application to living things. Used on inanimate objects,e.g chlorine, Hypochlorite, Copper sulphate, quaternary ammonium compounds. Antiseptics Microbicidal agents harmless enough to be applied to the skin & mucous membrane. e.g ;--- Mercurials, Silver nitrate, iodine, Alcohols, Detergent Antiseptics ;------ Low concentration Disinfectants ;------ High concentration

Phenol coefficient : 

Phenol coefficient The ability of microorganism to be killed by a chemical . A quantitative measure of this variation is expressed as Phenol coefficient Ratio of the conc of phenol to the conc of the agent required to cause the same amount of killing under the standard conditions of the test. No of survivors (N) are inversely proportional to Concentration of chemical agents and time of application

A satisfactory chemical agent : 

A satisfactory chemical agent Should be.;--- a true sterilizer Non toxic Non- irritating Be active against a wide range of pathogens Should not be inhibited by organic matter. Should have a rapid action

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Types of chemical agents 1.DISRUPTION OF CELL MEMBRANE

Personal hygiene & care of hands : 

Personal hygiene & care of hands Rechargeable battery operated Spray cans

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first disinfectant used in the operating room (by lister—1860s) but rarely used today b/c it is too caustic, Efficient disinfectant -- PHENYL (bath room disinfection) a.Cresols --- active ingredient Lysol b. Chloroxylenol (Dettol); Halogenated phenolic compound, less irritative , less toxic but less efficient, inactivated by organic matter. c. Chlorhexidine (Hibitane or Hebescrub) Preoperative hand disinfection by the surgical team, Bladder irrigant during cystoscopy Incorporated in the vaginal cream Useful in cutting down the staphylococcal flora on the hands of nurses. 2. Phenols

2.Phenols : 

2.Phenols a.Cresols active ingredient Lysol b. Chloroxylenol (Dettol ) Halogenated phenolic compound less irritative , less toxic but less efficient, inactivated by organic matter c. Chlorhexidine (Hibitane or Hebescrub) Preoperative hand disinfection by the surgical team, Bladder irrigant during cystoscopy Incorporated in the vaginal cream Useful in cutting down the staphylococcal flora on the hands of nurses.

2.Phenols : 

2.Phenols d. 1% Hexachlorophene (Germicidal) Germicidal soaps used for cleaning hands Active against gram positive, less for gram -negative organisms ---pseudomonas survive Limited use because of its neurotoxicity.

DISRUPTION OF CELL MEMBRANE3.Detergents : 

DISRUPTION OF CELL MEMBRANE3.Detergents Cationic Surface-active agents (Quaternary ammonium compounds) Dissociate in aqueous sol. into ;-- large complex cation ( Quaternary ammonium group-- responsible for surface activity) and a smaller inactive anion e.g Cetrimide ---- (Citavlon, CTAB,Savlon) Moderately bactericidal active against GM+ive organisms , can be used for preoperative toilet of skin Disadv; Pseudomonas survive in the solution, adsorbed by fabrics

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Surface active agents;------For disinfect ion of all dental & medical instruments (TertiaryAlkylamins)

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Surface active agents;------For disinfect ion of all dental & medical instruments (TertiaryAlkylamins)

Chemical agents 2. MODIFICATION OF PROTEINS Halogens : 

Chemical agents 2. MODIFICATION OF PROTEINS Halogens True sterilizers but inhibited by organic matter 1. Iodine Most effective skin antiseptic used in medical practice Should be used prior to obtaining blood culture& installing I/ V Catheters Two forms---- Tincture iodine : solution of iodine & KI. (2% each) in ethanol (90%) Disadv;--- irritant to the raw areas , allergic contact dermatitis , SO should be removed with alcohol. Iodophors : Complexes of iodine with non-ionic detergents (Povidone-iodine ----Betadine) used for scrubbing up preoperatively Less irritating ,stains less as compared to Tincture iodine

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2.Chlorine; A powerful oxidizing agent and a disinfectant used as a disinfectant to ; purify the water supply to treat swimming pools. an active part of hypochlorite (HOCL) (Bleach----Chlorox) Widely used for disinfection of hospital environment & fomites Active against viruses (hepatitis) Disinfectant for household purposes; Abrasive powders containing hypochlorite e.g vim, ajax ---useful for scouring baths& sinks. 2.MODIFICATION OF PROTEINS Halogens

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Chemical agents 2.MODIFICATION OF PROTEINS Halogens

2.MODIFICATION OF PROTEINS : 

2.MODIFICATION OF PROTEINS 2.Heavy metals Mercury & silver has the greatest antimicrobial activity out of heavy metals e.g. Mercurochrome ----skin antiseptic Silver sulfadiazine, used to prevent the infection after burns. Silver nitrate drops (prevention of Gonococcal ophthalmia neonatorum

2.MODIFICATION OF PROTEINS : 

2.MODIFICATION OF PROTEINS 3. Hydrogen peroxide An oxidizing agent –attacks sulfhydrl gps, ---inhibit enzymatic activity Antiseptic used to---- clean wounds & to disinfect contact lenses. Affectivity limited because of tissue catalase

2.MODIFICATION OF PROTEINS : 

2.MODIFICATION OF PROTEINS 4. Aldehydes Formaldehyde gas ;--- Formalin--- 37% solution of formaldehyde gas in water Hot gas penetrates better into the fabrics, much more useful. Powerful disinfectant , a true sterilizer but slow action , irritating odor . Combination of dried saturated steam and formaldehyde, with the main advantage being that sterilization is achieved at a low temperature. Heat sensitive materials Uses;---- Room disinfection , Operation theatre

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Sterilisation by ethylene oxide A highly penetrative non corrosive gas Broad-spectrum cidal action For heat sensitive materials including electrical equipment

Formaldehyde gas : 

Formaldehyde gas

4.Aldehyde 2% GLUTARLDEHYDE : 

4.Aldehyde 2% GLUTARLDEHYDE Sterilization Disinfection 8-10 Hrs used for :- Pneumatic circuits. i.e.- ventilator tubing O2 masks ventury devices nebulizer chamber 15-30 min used for dis -infecting endoscopes Respiratory tubing's (Cidex) 10 times more potent than formaldehyde less toxic used to sterilize the respiratory therapy equipment.

2.MODIFICATION OF PROTEINS : 

2.MODIFICATION OF PROTEINS 5.Ethylene oxide --gas Extremely well penetrating power Used extensively in the hospitals for sterilization of heat sensitive materials such as surgical instruments, endoscopes , fabrics & plastics . Require exposure 4-6hrs followed by aeration to remove absorbed gas.

ETHYLENE OXIDE(EO) : 

ETHYLENE OXIDE(EO) Used for polythene and plastic items E.g.:- Ambu bag ,Baines circuit , Domes , Biopsy Needle , Electric items , Rubber items Pre-caution:- Scrupulous cleanliness and dryness Adequate aeration at least 12Hrs

2.MODIFICATION OF PROTEINS : 

2.MODIFICATION OF PROTEINS 6.Alkalis & acids Strong alkalis & acids kill microorganisms by denaturing proteins Most bacteria are susceptible except few like Myco T.B (2% NaoH for sputum liquifaction) Weak acids are Bacteriostatic like Benzoic acid , Citric acids , propionic acid used as food preservatives

Chemical agents3.MODIFICATION OF NUCLEIC ACIDS : 

Chemical agents3.MODIFICATION OF NUCLEIC ACIDS A variety of dyes not only stain but also inhibit the growth of microorganisms’ 1. Aniline dyes (Bacteriostatic) (a) Crystal violet -----An skin antiseptic as well as a stain for bacteria. Its action is based on binding of positively charged dye molecule to the negatively charge phosphate group of the nucleic acid. Malachite green.---- a component of Lowenstein Jansen’s medium 2. Acridine compounds .;---- Acriflavine , Proflavine

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Chemical preservatives Bacteriostatic agents Used to preserve food ,Should be non toxic

Disinfection : 

Disinfection Cleaning of items is essential before disinfection is under-taken and the efficiency also depends on: the nature of micro-organisms; the load of micro-organisms; the duration of exposure to the agent; the temperature

DisinfectionMethods : 

DisinfectionMethods Disinfection with low-temperature steam 73o for a period of 20 minutes at a pressure below atmospheric. Disinfection with boiling water At 100o C at normal pressure for 5 minutes. Disinfection with formaldehyde Formaldehyde gas is a broad-spectrum antimicrobial agent. This process utilises a cabinet which is a airtight and circulates gaseous formaldehyde up to 50oC. Disinfection with glutaraldehyde A 2 % solution of glutaraldehyde is effective against most bacterial viruses, including hepatitis B and C and HIV,

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Flexible endoscopes Thorough cleansing is essential The degree of decontamination is proportional to the time of immersion. Safeguards for equipment during sterilisation Through cleaning; Appropriate packing Arrangements of articles so that all surfaces are directly exposed to the agent. Chemical indicators Interval monitoring of sterilization process with chemical, thermal and, sometimes, biological indicators;

DISINFECTION OF HANDS : 

DISINFECTION OF HANDS

Specific antiseptics ; recommended for hand antisepsis : 

Specific antiseptics ; recommended for hand antisepsis 2-4% chlorhexidine ---Hibitane or Hebescrub 5-7.5% ----Povidone -iodine 60-90%--- Alcoholic hand rubs (waterless , alcohol based gel) 1% triclosan

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Practical sterilization--- hand antisepsis

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Practical sterilization--- hand antisepsis

Practical sterilization : 

Practical sterilization Presterilized disposable equipments used in the hospitals;----Syringes, needles, catheters, gloves, scalpels. Autoclaved ; Dressings, theatre apparels, gloves Surgical instruments;---Autoclaved, heating of sharp edged instrument may leads to blunting.

Practical sterilization : 

Practical sterilization Catheters--- Disposables;---by ionizing radiations. Boiling, Glutaraldehyde, Mercuric chloride, Chlorhexidine. Cystoscopes;--- pasteurization, Glutaraldehyde, chlorhexidine. Face masks ;---pasteurization,(chemical disinfection may damage skin) OT;---Plenum ventilation ( Hepa filters, UV filters)

VENTILATOR : 

VENTILATOR STERILE WATER FOR NEBULIZER & HUMIDIFIER PNEUMATIC CIRCUIT TO BE CHANGED WHEN VISIBLY SOILED USE HEAT & MOISTURE EXCHANGE FILTER CONDENSATE IN TUBING TO BE DRAINED ONLY TO THE WATER TRAPS HUMIDIFIER DOMES (AUTO CLAVED OR STERILIZED BY 2% GLUTARALDEHYDE)

PNEUMATIC CIRCUIT : 

PNEUMATIC CIRCUIT WASHED UNDER RUNNING WATER IMMERSED IN 2% GLUTARALDEHYDE FOR 8 TO 10Hrs Radiation

2% GLUTARLDEHYDE : 

2% GLUTARLDEHYDE Sterilization Disinfection 8-10 Hrs used for :- Pneumatic circuits. i.e.- ventilator tubing O2 masks ventury devices nebulizer chamber 15-30 min used for dis -infecting endoscopes Respiratory tubing's

TRACHEOSTOMY CARE : 

TRACHEOSTOMY CARE TO BE GIVEN EVERY FOUR HOURS SKIN AROUND TRACHEOSTOMY TUBE CLEANED WITH BETADINE INNER CANNULA OF METAL TRACHEOSTOMY -CLEANED UNDER RUNNING WATER -IMMERSED IN HYDROGEN PEROXIDE FOR 10MTS - WASHED WITH WATER AND GAUZE WICK -BOILED FOR 10 MINTS AND REPLACED ONCE IT IS COOL

TRACHEAL SUCTIONING : 

TRACHEAL SUCTIONING USE DISPOSABLE SUCTION CATHETER SUCTION JAR & TUBING CHANGED EVERY 24 Hrs FILLED WITH 7% LYSOL FOR 1Hr CLEANED WITH SOAP UNDER RUING WATER

SUCTION TRAYS : 

SUCTION TRAYS TO BE CHANGED EVERYDAY SUCTION CUPS -CHANGED AFTER EACH USE - IMMERSED IN 7% LYSOL FOR 1Hr - WASHED WITH SOAP &WATER - SENT FOR AUTOCLAVING

ICU – ISOLATION ROOM : 

ICU – ISOLATION ROOM SINGLE CLOSED CUBICLE CASES – OPEN TB , ANTHRAX, MRSA etc… UV LIGHT FOR DISINFECTION

ICU INSTRUMENTS : 

ICU INSTRUMENTS SEPARATE:THERMOMETER, AMBU BAG, BAINS CIRCUIT, STETHOSCOPE, BIOPSY NEEDLE - EO GAS STERILIZATION DISPOSABLE SUCTION CATHETER

ALL REUSABLE ITEMS : 

ALL REUSABLE ITEMS WASHED UNDER RUNNING WATER 2% GLUTARALDEHYDE

DOUBLE AUTO CLAVING : 

DOUBLE AUTO CLAVING HIV , HBV , HCV , MRSA INFECTION FOR RE- USABLE NON – SHARP MATERILE PLACED IN REDBAG

LINEN : 

LINEN SOAKED IN 7% LYSOL hrs

SEPARATE AREA(UTILITY ROOM) : 

SEPARATE AREA(UTILITY ROOM) FOR EQUIPMENT DISINFECTION PNEUMATIC CIRCUITS , O2MASK etc SUCTION JAR CLEANING AND DISINFECTION CHEST DRAINAGE BOTTLES LINEN DISINFECTION

ROUTINE SURVEILLANCE IN ICU – ONCE IN A MONTH : 

ROUTINE SURVEILLANCE IN ICU – ONCE IN A MONTH

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Thank you

Introduction : 

Introduction Surgical infection still causes considerable morbidity and high costs to the health- care- systems, and is becoming increasingly important in medico-legal aspects. Wound infection results from bacterial contamination of the wound.

Infection rate is proportionate to: : 

Infection rate is proportionate to: Number of bacteria. Type of bacteria. Incisions involving mucus surfaces. Sites of existing infection in the body. The use of prosthetic implants.

The theatre : 

The theatre The siting of theatre. Clean and dirty areas should be separated and well demarcated Sterile area. The scrub room Designing of the scrub room should incorporate: Tow doors leading to corridor and into the theatre. Sinks with taps that can be manipulated by foot pedals and soap holders that can be manipulated by foot pedals or the elbows. Good drainage and suitable panels incorporated in the sink to prevent splashing of clothes; Anti-slip floors; Easily cleaned shelves for gown packs and gloves; Adequate facilities for separate disposal of linen and papers; Brushes for cleaning finger nails.

The operating room : 

The operating room The operating room should have a double-door entrance from the anaesthetic room and a double-door exit into the clean corridor. There will also be two small door entrances from the clean store room where sutures, dressings and needles kept and opening from the scrub room. There is also a single exit door to the dirty corridor for removal of drapes, instruments and waste products at the end of the procedure. All the doors should be well sealed in order to comply with the air ventilation system

The operating room : 

The operating room The operating table should be adjustable with all working parts sealed. The cushions should be easy to clean and in good repair. The lights should be adjustable. The plasterwork and floor should be well sealed. Fixed surfaces in the operating theatre should be avoided and reliance placed on steel trolleys. X-ray viewers should be inset into the wall and kept in good repair, as should electric sockets.

The operating room : 

The operating room Control of air quality 20 air changes per hour using a 5 – mm pore size filter. Air changes this can be reduced to 200/CFU/m3. Orthopaedic operating theatres utilise ultra-clean air where the bacterial count is kept below 10 CFU/m3. Rapid high-volume flow of air over the operating theatre with high – efficiency particulate filters. Essential measures, in addition to efficient air ventilation and filtration, include: Reduction in the number of individuals in the theatre; Avoidance of excess movement of individuals in the theatre; Ensuring that the air vents are not obstructed and that the doors are closed.

STERILISATION Methods : 

STERILISATION Methods Sterilisation by steam Using autoclaves: The combination of pressure, temperature and time with the moist heat is important: 134o (30 lb/in.d2) for hold time of 3 minutes; 121o (15 lb/in.d2) for hold time of 15 minutes; prepacked materials and instruments are processed through a porous load autoclave, which incorporates a prevacuum cycle necessary to extract air. Monitoring All autoclaves must be regularly maintained Pressure and temperature Bowie-Dick test Chemical indicators Brownes tubes or impregnated tapes, are used

THEATRE STAFF : 

THEATRE STAFF Bacterial infection Infected skin lesion, such as a boil, paronychia or carbuncle, known carrier state, particularly in the nares and the presence of an acute bacterial infection, particularly an upper respiratory tract infection, must lead to the exclusion of such a person from the team. Showering Clothing and gowning Masks Their use is indicated in implant and orthopaedic surgery. They offer protection to the wearer. Reduction of speech at the operating table is important. Gloving Scrubbing up Brushes should only be used for cleaning fingernails. A scrub up time of 3-5 minutes with chlorhexidine soap or povidone iodine soap is utilised;

THE OPERATION : 

THE OPERATION Preoperative preparation of patient Factors to be taken into account include the following: Preoperative showering A short preoperative hospital stay is important; Preoperative screening Shaving Transport Skin preparation Washed with detergent-impregnated soap Chlorhexidine or povidone – iodine,

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The vagina and perineum should be cleaned with aqueous chlorhexidine and cetrimide solution. Adhesive plastic drapes are widely used and have the advantage of keeping either cotton or fabric drapes in place, but there is no evidence that they reduce the incidence of wound infection.

The procedure : 

The procedure High standards of asepsis in the operating theatre. Avoid injury to the patient and staff Sharps should be kept in receivers Instruments should not be left on drapes Disposable instruments, should be discarded Instruments should be well maintained When the preliminary count is done at the start of an operation, instruments should be checked so that all joints, nuts, screws and surfaces that slide over each other are clean with no detritus present, and move freely. Counts Instrument and swabs should be counted carefully

Dealing with High – risk infection procedures : 

Dealing with High – risk infection procedures Hepatitis B and C viruses HIV and cytomegalovirus; General measures: Education of staff The availability of advice for staff in the event of injury Identifying high-risk patients Reduction of the number of staff Removal of all extraneous equipment Staff should avoid contact with contaminated body fluids When handling potentially contaminated blood or body fluids, scrub staff should use non permeable gowns and masks with eye protection and should double glove.

Dealing with High – risk infection procedures : 

Dealing with High – risk infection procedures Calculating personnel should use plastic aprons and wear gloves Spills should be dealt with by staff wearing gloves Care should be taken with the handling of sharps. Swab should counted Disposable equipment should be placed in yellow bags. Soiled linen should be placed in special alginate bags Conclusion Prophylactic and therapeutic have not reduced the essential role of asepsis and sterile precautions.

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