ETO (Ethylene oxide) is used for the following EXCEPT:
Correct Answer: Fumigation of rooms
Description: Ans. b (Fumigation of rooms) (Ref. Ananthanarayan, Microbiology, 7th ed., 42)# Liquid and gaseous ETHYLENE OXIDE destroys bacteria, viruses, fungi, and various spores.# It is also flammable and toxic, and it will cause severe burns if it comes in contact with the skin.# Gas sterilization with ETO is an excellent method for sterilization of most heat-sensitive materials:- Telescopic instruments,- Plastic and rubber goods,- Sharp and delicate instruments,- Electrical cords, and- Sealed ampules.# It has largely replaced soaking in antiseptics as a means of sterilizing materials that cannot withstand autoclaving. Ethylene oxide is toxic and represents a safety hazard unless used according to strict regulations.STERILIZATION# The only completely reliable methods of sterilization in wide current use for surgical instruments and supplies are:(1) Steam under pressure (autoclaving),(2) Dry heat, and(3) Ethylene oxide gas.# Autoclaving- Saturated steam at a pressure of 750 mm Hg (14.5 psi above atmospheric pressure) at a temperature of 120degC destroys all vegetative bacteria and most resistant dry spores in 13 minutes. Sterilization time is markedly shortened by the high-vacuum or high-pressure autoclaves now widely used.# Dry Heat- Exposure to continuous dry heat at 170degC for 1 hour will sterilize articles that would be spoiled by moist heat or are more conveniently kept dry. If grease or oil is present on instruments, safe sterilization calls for a 4-hour exposure at 160degC.# Gas Sterilization: ETOAgentCommentsEthyl alcohol, isopropyl alcohol, and n-propanol# Exhibit rapid, broad-spectrum antimicrobial activity against vegetative bacteria, viruses, and fungi but are not sporicidal.# Activity is optimal when they are diluted to a concentration of 60-90% with water.Aldehydes# Glutaraldehyde is used for low-temperature disinfection and sterilization of endoscopes and surgical equipment.# It is normally used as a 2% solution to achieve sporicidal activity.# Formaldehyde is bactericidal, sporicidal, and virucidal - fumigation.Biguanides# Chlorhexidine is widely used in handwashing and oral products and as a disinfectant and preservative.# Mycobacteria are generally highly resistant.Bisphenols# The bisphenols are widely used in antiseptic soaps and hand rinses.# In general, they are broad-spectrum but have little activity against Pseudomonas aeruginosa and molds.# Triclosan and hexachlorophene are bactericidal and sporostatic.Halogen-releasing agents# The most important types of chlorine-releasing agents are sodium hypochlorite, chlorine dioxide, and sodium dichloroisocyanurate, which are oxidizing agents that destroy the cellular activity of proteins. # Hypochlorous acid is the active compound responsible for the bactericidal and virucidal effect of these compounds.# At higher concentrations, these compounds are sporicidal.# Iodine is rapidly bactericidal, fungicidal, tubercuiocidal, virucidal, and sporicidal.# lodophors (e.g., povidone-iodine) are complexes of iodine and a solubilizing agent or carrier, which acts as a reservoir of the active l2.Organic acidsOrganic acids are used as preservatives in the pharmaceutical and food industries.Benzoic acid is fungistatic.Propionic acid is both bacteriostatic and fungistatic.Hydrogen peroxideHas broad-spectrum activity against viruses, bacteria, yeasts, and bacterial spores.Sporicidal activity requires higher concentrations (10-30%) of H202 and longer contact times.Quaternary ammonium compoundsThey have been used for a variety of clinical purposes (e.g., preoperative disinfection of unbroken skin) as well as for cleaning hard surfaces.They are sporostatic.They inhibit the outgrowth of spores but not the actual germination process.They are also mycobacteriostatic and have an effect on lipid-enveloped but not lipid-nonenveloped viruses.Vapor-phase sterilantsHeat-sensitive medical devices and surgical supplies can be effectively sterilized by vapor-phase systems employing ethylene oxide, formaldehyde, hydrogen peroxide, or peracetic acid. ETO is highly penetrative non-corrosive gas. It is not recommended for ventilator respiratory equipment or soiled instruments because organic debris, including serum, has a marked adverse effect.Educational Points:TermDefinitionSterilizationA physical or chemical process that completely destroys or removes all microbial life, including spores.DisinfectantsProducts or biocides used to kill microorganisms on inanimate objects or surfaces.Disinfectants are not necessarily sporicidal, but are sporostatic, inhibiting germination or outgrowth.Antiseptic AsepticA biocide or product that destroys or inhibits the growth of microorganisms in or on living tissue.Characterized by the absence of pathogenic microbes.
Category:
Microbiology
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