Control of microbes by physical and chemical agents

Question 1

Differentiate between disinfection,

sanitisation and sterilisation.

Answer 1

Sterilisation is the process whereby all living organisms including viable bacterial spores and viruses are killed

Disinfection describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects

Santisation is the reduction of the microbial population on inanimate (non-living) sources to levels set by the
public health authorities.

Question 2

Define antisepsis

Answer 2

Antisepsis refers to the use of chemical compounds to reduce the number of bacteria to levels that are
considered safe on skin surfaces thereby preventing the killing or inhibition of micro-organisms

Question 3

Categorise disinfectants as high,

intermediate or low-level disinfectants

Answer 3

High –level disinfectants are used on equipment that is used for invasive procedures such as some types of
endoscopes and surgical instruments that cannot withstand the high temperatures used in sterilisation.
These disinfectants are effective against all microbial pathogens with the exception of bacterial spores.

Intermediate-level disinfectants are used on equipment or surfaces where the presence of bacterial spores
and other highly resistant microbes are highly unlikely.

Low-level disinfectants are used on non-critical instruments and devices such as blood pressure cuffs,
stethoscopes and electrodes.