Principles of Sterilization and Disinfection

#Sterilization & Disinfection -Sterilation, a process that destroys all viable mo. Including vitused & endospores -Disinfection a process to destroy vegetative pathogens, not endospores. inimaste object. -Antiseptic disinfectant applied directly to exposed body Surfaces ex wound. -Sanitization, any cleaning technique that mechanically removes m.o. -Degermination mechanically removing mo from Surface &Skin ex Surgical hand Scrubbing, or wiping skin e alkohol prior to Venipuncture -Sepsis bacterial Contamination - Asepsis absence & Significant Contamination. -Bactericidal (microbicidal) --cidal means kill -Bacteriostatic (micro biostatic)-static means inhition of growth & multiplication. #aim of Steralization prevent infection. ideal field for Surgical operation is (CSteriler) = free of Contamination How to Sterilization works? factors influencing Ability to kill microbes D Strength of the killing agent Time that the agent has to act. 3 rate of microbe death doubles e every 10°c rise in temp. Type & microloe enviroment around the area to be de contaminated Number of microbes to be killed. Critical of doject which enters normally Sterile tissue of the Vascular System or through which blood flows should be sterile. Semicritical doject touch mm or skin (not intact) require disinfection process (High level disinfection HLD)) -Non Critical objects that touch only intact skin require low-level disinfection. most Resistant least Resistant Endospores> Mycobacteria fungal Spores> non- Enveloped viruses (polio, rotavirus, rabies) > Vegetative fungul Cells > Enveloped Viruses (Herpes, Hepc, HIV) Vegetative Bacteria C Types of disinfectants high level disinfectant kill all m.o w/n used in optimum Concentration >Intermediate level disinfectant destroy All M.Or not include bact spore) ✓ low level disinfectant destroy only Vagetative bact, enveloped viruses & Fungi Method physical chemical Sunlight heat skall mo by deniturosong their craymes & other proteins. heat resistance varies among microbes. Thermal Death points lowest Temperature at which all of the microbes will be killed in ten minutes Thermal Death Time Minimal length of time in which all bacteria will killed at given temp. ③ ways of heat energy can applied to @mast hot-dry heat-pasteurization. Omoist heat so kills by denaturing proteins &c.m more effective than diy haut ott₂O better Conducter of heat than air s A. Boiling kill vagetative Cell of bacteria & fungi Protozoan trophozoites, & most viruses ein 10 mint QEndospores protozoan Cyst & Some Viruses Can Survive boiling Autoclaves hig Temp Steam plus pressure mast fig used in Sterilization. ↑ Pressure boiling water. 1212, 15psi, 15 min Dry heat Hot air oven used to Sterilise material Such as glassware, chemicals & Sealed Containers -incineration used for disposal of hospital waste. Pasteurization heating of milk to 62°C for 30 mint followed by rapid Cooling or, 72℃ for 20 Se Kills Vagetative bact of milk corn pathogen QCMycobacteriura baris, Salmonella, Streptocrccus, Listeria & & Brucella Qbut not sterilize the milk filtrations Pemuat of mo by passage materiale Small pores. of Liquid through a screen like oxed to Sterila beat Sensitive Materials like Vaccines enzymes antibiotics & Some Culture Media, most used filter is nitrocellulose e pore Size 0.22 Um es retain all bacteria & Spores Radiation D Ianized Radiation Gamma/ays, X rays, electron beams, higher energy rays. →Caused DNA mutation & preduce peroxides used to Sterilize pharmaceuticals & disposable Medical Supplies →Disadvantages-Pentrades human tissues. May Cause genetic mutations in humans. 2 non ionizing radiations: induse dimer formation in DNAstrands & interferee DNA replication infrared radiation Oltra Violet radiation. Chemical agents chemical agerets ait by one of 3 mechanisms se disruption & lipd-contiung C.M Modification of Proteins ③ modification of DNA. Chemical agent #factors influencing antimicrobial [Chemial] activity- →Concentration & kind of agent →Time of exposure to the agent →Temp at which the agent is used →The Number of mo present. → the kind of mo present →The nature of material bearing the mo 3* Disruption of Cell membrane -phenol Alcohol QModification of Proteins -chlorine-Iodine heavy metal - Hydrogen Peroxide Formaldehyde & Glutaldehyde - Ethylene Oxide - Acids & Alkalis Phenol 1st disinfectant used in operating room chlorhexidine (chlorinated phend) used as hand disinfictant Prior to Surgery (Surgkal Scrub) & in Cleming of wounds. lalcohol Intermediate leud disinftarets denaturate proteins & disrupt Cytoplasmic membranes. Evaporates rapidly-both advantageous & disadvantageous. ↳ Suibbing of Skin e for ethanol prior to injection. Chlorine disinfectant to purfy the water Sugly ((treat Swimming pools)) hypochlorite (bleach, clorox) which used in home & hospitals. as disinfectant → powerful oxidizing agent QO SH kills by Cross linking essential Sulfhydryl groups in enzymes to form in active s-s di sulfide -SH HIS- Aldehydes Denaturate protein & mactive NAQ Glutaldehyde both disinfects (short exposure) & Sterilice (long exposure) formalin used in disinfection of rooms & instruments. (oxidizing agent) peroxides H₂O₂, Oeste, perectic acid kill by oxidatio of microbial enzymes HLD & antiseptics →H2O2 Can disinfect & Sterilize Surface of objects Ozone Treat Drinking water Perectic acid-effective sporocide used to sterilize equipment. (oxidizing agent Peroxides H₂OL, Oerne, perectic acid kill by oxidation of microbial enzymes HLD & antiseptics →H2O2 Can disinfect & Sterilize Surface of objects Oeone Treat Drinking Water Perectic acid-effective sporocide iced to sterilize equipment. Heavy metals •ions (Mercury & Silver) are antimicrobial Ble alter 3D shape protein, & their function low level bacteriostatic & fungistatic agents 17 Silver nitrate to prevent blindness Gaused by Nigorerhoom → Silver Suffaldiazine used to prevent infection of burn wounds Thirmerosal used to preserve → reserve Vaccines. Gaseus agents Ethylene Oxide, Propylene oxide, & propiolactone used in closed champers to Sterilize items. Denaturation proteins & DNA by Cross linking → used in hospital & dental offices Can be hazardous to people, often highly explosive, extremly poisonous & Carcinogenis