Question

1. Define the difference between sterilization and disinfection.

2. Define the difference between a disinfectant and an antiseptic.

3. List one chemical and one physical method of disinfection.

4. List two areas or items that would need to be sterilized.

5. Gram negative and gram positive organisms have different sensitivities to disinfectants and antiseptics. Explain why.

Answer 1

1. Sterilization is the process in which all living organisms including spores are killed. Disinfection is the elimination of most pathogens from inanimate objects.

2.Disinfectants are antimicrobial substances applied on inanimate objects while antiseptics are applied on living tissues.

3.Chemical method: Formaldehyde. Formalin (40% formaldehyde) is used for fumigation of rooms

Physical method: UV light

4.Bacteriological media & surgical instruments

5. The different sensitivities to bacteria to disinfectants and antiseptics is associated to cellular permeability.In general spores are most resistant followed by mycobacteria, then Gram negative followed by Gram positive. The Gram negative cell wall consist of an outer membrane which can limit the entry of disinfectants & antiseptics and thus prevent it from reaching target sites.