Disinfection Flashcards
Definition of Disinfection
process that eliminates many/all pathogenic microorganism except bacterial spores, on inanimate object
Definition of sterilisation
process that destroys/eliminates all forms of microbial life including spores
definition of cleaning
removal of visible soil (eg organic & inorganic matter), manually or mechanically using water with detergents or enzymatic products
definition of decontamination
removes pathogenic microorganisms from objects so that they are safe to use, handle & discard
high level vs low level disinfectant?
- high level disinfectant can kill all microorganisms except spores in a shorter period of time
- low level disinfectant kill vegetative bacteria, some fungi & virus when applied for a practical period of time (<10mins)
what is the active component in disinfectants that kill microorganisms
biocides
describe the spectrum of activity of biocides
broad spectrum of activity, have multiple targets
factors affecting efficacy of disinfectant
- no & level of microbes
- concentration & potency of disinfectants
- innate resistance of microbes
- exposure time
- physical & chemical factors - pH, temp, water hardness, relative humidity
- biofilm
- presence if inorganic & organic matters
alcohol moa
denature proteins, activity increase with water
inhibit production of essential metabolites require for rapid cell division
what is the optimal concentration for alcohol to work as disinfectant?
60-90%
uses of alcohol
antisepsis, disinfectant, preservatives
what is the spectrum of activity of alcohol
bactericidal, sporicidal, fungicidal, tuberculocidal
disadvantage of alcohol
volatile - short contact time
microbicidal activity affected by presence of organic matter
not sporicidal
ammonia moa
saponifying lipids within enveloped of microorganism
what to be cautious of for ammonia?
do not combine with chlorine, produce chloramine which is toxic
is ammonia safe?
no, it irritate eyes & gastric system
aldehyde moa
alkylation of sulfhydryl, hydroxyl, carboxyl & amino groups. disrupt protein, RMA & DNA synthesis
describe ortho-phthaldehyde
clear, pale blue solution
less potent as alkylating agent
aromatic ring which is lipophilic, increase uptake through outer layer of mycobacteria & gram -ve bacteria.
sporicidal by inhibiting spore germination process
advantage of ortho-phthtaldehyde
excellent stability over wide range of pH
no precipitable odor
not irritant to eyes & nasal passage
excellent material compatibility
disadvantage of ortho-phthtaldehyde
stain protein grey
what are the 2 kinds of biguanides
chlorhexidine & alexidine
