Chemical

DefinitionDefinition

Sterilization: The freeing of an article from all living organisms including bacteria and their spores.

Disinfection: Removal of some types of pathogenic organisms usually not including spores.

DISINFECTANT:

Chemical substances used for sterilization of inanimate objects (toxic to human)

ANTISEPTIC:

Chemical substance that used for sterilization of animate objects (not toxic to human)

Chemical MehodsChemical Mehods

Destroys1.All vegetative bacteria (except tubercle bacilli)

2.Enveloped viruses3.Some fungi

Examples1.Phenol group2.Quaternary ammonium compound

PhenolPhenol

Mouth washesScrub soapsSurface and household disinfectantsPhenol 5% used as disinfectant of stool in

typhoid or sputum in T.B

Quaternary ammonium compoundQuaternary ammonium compound

Surface disinfectantContraindicated as antiseptics

DestroysAll vegetative bacteria (including

tubercle bacilli)Enveloped and some non-enveloped

virusesMost fungi

ExamplesAlcoholHydrochloritesIodine and iodophores

AlcoholAlcohol

Examples:1.Ethyl alcohol2.Isopropyl alcohol

Uses:1.Topical antiseptics2.Disinfect the surface of medical

equipment

HypochloriteHypochlorite Examples: Clorox

Uses: Household bleach Surface disinfectant Water disinfectant

Iodine and Iodophore Iodine and Iodophore disinfectantsdisinfectants

1. Antiseptic2. Disinfection of blood

culture bottles3. Disinfection of

medical equipments such as thermometers and endoscopes

DestroysAll vegetative bacteria (including tubercle

bacilli)Enveloped and some non-enveloped virusesFungiSome bacterial spores

ExamplesH2O2GluteraldehydeFormaldehydePeracetic acid

H2O2H2O2

Mouth gurgleAntiseptic to clean wounds

GluteraldehydeGluteraldehyde

Example: Cidex

Uses: Very potent disinfectant

Disadvantages: Highly toxic used under trained supervision in a

well ventilated setting and with appropriate personal protective equipment

FormaldehydeFormaldehydeExample:Formalin, formadon

Uses:Disinfectant in both liquid and gaseous

state

Disadvantages:Potential carcinogen

ClassificationItemsExamplesReprocessing

Critical items (high risk)

Items that penetrate soft tissues

Surgical InstrumentsIUDVascular cathetersimplants

cleaning followed by sterilization

Semicritical items

(intermediate risk)

Items that in close contact with mucous membranes or with non intact skin

Respiratory equipments, flexible endoscopes, laryngoscopes, endotracheal tubes, thermometers.,

Cleaning followed by high level disinfection

Non critical item

(low risk)

Items that come in contact with normal and intact and inanimate environment skin

StethoscopeWalls, floors, ceiling,Furniture, sinks.

Cleaning and /or low level disinfection

ItemMethod of sterilization

Cat gutIonizing radiation

Endoscopes2% Gluteraldehyde 30 min, 10% phenol 6 hrs, ethylene oxide

Disposable syringesEthylene oxide, ionizing radiation

Egg/serum mediaInspissation (80 o C,30 min, for 3 days)

Faeces, urine, vomitusBleaching powder, cresol

Heart-lung machineEthylene oxide

Endoscope washer

ItemMethod of sterilization

Infected materialsIncineration

Lab mediaAutoclave(121 o C, 20min)

Oils, powders, glasswareHot air oven (160 o C 2 hrs, 180 o C 1 hr)

Operation theatre/roomFormaldehyde gas

Plastic/polythelene tubes Ethylene oxide, 2% gluteraldehyde

Serums, fluidsWater bath( 56 o C, 1 hr)

SkinTincture iodine, 70% methylated alcohol(spirit), savlon

ItemMethod of sterilization

SputumBurning, autoclave

Suture materialAutoclave

Thermometer, cheatle forceps10% chlorhexidine+ cetrimide 1% for 10 min

Toxins, antibiotic solutions, blood products

Filtration

VaccinesVaccine bath (60 o C , 1 hr)

Surgical instrumentsH2O2 gas plasmaAutoclaveInfra-red (metal instruments)

GownsAutoclave