Antiseptics and Disinfectants Flashcards
define disinfectant
a chemical applied to inanimate objects to kill or inhibit further growth of microorganisms. What they kill depends on the product
what is an antiseptic?
similar to disinfectant but can be used on living tissues (e.g. patient preparation)
define detergent
solutions with cleaning activity, usually used to remove organic material that could affect the efficacy of disinfectants
define sterilisation
when a product is freed of all microorganisms
define asepsis
removal of all microorganisms and spores usually removed through sterilisation
define disinfection
removal of microorganisms
what two states do bacteria exist as?
spores and vegetative
what are vegetative bacteria?
bacteria that are living and replicating
what are spores?
dormant bacteria resistant to lots of chemicals
how are gram + and gram - bacteria differentiated?
how they stain
How may bacteria present?
rods, cocci. In singles, pairs or a cluster
give an example of 2 gram positive bacteria
staphylococcus and bacillus
give 2 examples of gram negative bacteria
E coli, Pseudomonas
what are the 2 types of viruses?
enveloped and non enveloped
describe enveloped viruses
surrounded by a lipid layer which makes them easier for disinfectants to break down
describe non-enveloped viruses
much more resistant to chemicals as outer layer is not lipid based
give 2 examples of enveloped viruses
canine distemper and feline immunodeficiency virus
give examples of non-enveloped viruses
parvovirus and feline calicivirus (khalisi)
what are protozoa?
single celled organisms
what are prions?
folded proteins
describe the ideal disinfectant
broad spectrum but particularly effective against HAI’s
non-irritant and non-toxic
easy to use on inanimate objects without causing corrosion or stains
stable and not easily inactivated
cost effective
rapid mode of action
remains on the surface for full contact time
not deactivated by organic matter or detergents
what factors should be considered when choosing a disinfectant or antiseptic?
what will it be used for (living tissue/inanimate objects)
degree of organic matter present
contact time (and time available to you - e.g. not extending anesthetic unnecessarily
is it being used for regularly encountered bacteria or isolation cases
what are the 6 types of disinfectants/antiseptics
alcohols aldehydes biguanides halogens QAC's phenols
How do alcohols work?
cause cell membrane damage
how fast does alcohol act?
fast
is there any residual activity of alcohol?
no - evaporates quickly
what is alcohol effective against?
broad spectrum but not non enveloped viruses or spores
what is the clinical use of alcohol?
hand disinfection
patient prep
how do aldehydes work?
denature proteins
what are two types of aldehydes?
formaldehyde and gluteraldehyde
why are aldehydes not often used?
they are carcinogenic
what are aldehydes effective against?
broad spectrum including non enveloped viruses and spores
what are aldehydes not used for due to their toxicity?
cleaning
what are aldehydes used for?
sample preservation
how do biguanides work?
alter permeability of cell membrane
what is the problem with biguanides?
inactivated by organic material
do biguanides have good residual action?
yes
what are biguanides effective against?
gram + and some gram - bacteria, limited fungi
what are biguanides not effective against?
spores or mycobacteria
what is the clinical use of biguanides?
patient prep and surgical scrub
give an example of a biguanide
chlorhexidine (hibiscrub)
What are halogens?
chlorine and iodophors
what are halogens effective against?
broad spectrum including unenveloped viruses
what are halogens used for?
chlorine - cleaning (bleach)
iodophors - skin disinfectant
what does QAC stand for?
Quaternary ammonium compounds
what effect do QACs have?
inactivate enzymes, denature proteins
what is the residual activity of QACs?
some
what are QACs effective against?
broad spectrum but not effective against unenveloped viruses, mycobacteria and spores
what are QACs used for?
surface disinfectant
what is the effect of phenols?
denature proteins and disrupt cell membranes
what is an issue with phenols?
toxic at certain concentrations and toxic at all times for cats
what are phenols effective against?
broad spectrum but no unenveloped viruses or spores
what are phenols used for?
surface disinfectants
what is most important when using disinfectants?
read the labels to ensure correct disinfectant and concentration are used for the circumstances
