Antiinfectives Flashcards
(58 cards)
what are high level chrmical sterilants
destroy all microorganisms
aldehydes, hypochlorites, peroxygenes
what are low level disinfectants
destroy most bacteria, some viruses and fungi
excludes TB, some viruses, fungi, bacterial spores, prions
what are some intermediate-level disinfectants
destroy all bacteria, most viruses and fungi
excludes some viruses, bacterial spores and prions; like alcohols, phenolics, iodine
what are antisepsis disinfectants
work on living tissues
decrease wound infections/normal skin flora prior to surgery
decrease spread of infection by hand cleansing
what are the properties of 4% chlorhexidine gluconate antiseptic
high activity in immediate, persistent, residual disinfectants
what are the properties of alcohol and chlorhexidine antiseptic
high activity in immediate, persistent and residual disinfectants
what factors affect choice of chemical agent
higher bioburden required higher concentrations and longer expsore times
biofilms are more resistant to disinfectants
what is transient bacteria
gram negative
like e.coli
what is resident bacteria
gram positive
staph.a
what effect does organic matter have on sterilisation
can reduce antimicrobial capacity
what effect do divalent cations have on sterilisation
reduced activity and stabalise cell walls, block disinfectant adsorption sites
what effect does dilution have on sterilisation
higher conc of disinfectant increases efficacy and reduces exposure time, but dilution does not affect killing capacity of all disinfectants in the same way
what is the suspension test
dilutions of disinfectant added to standardised bacterial suspension in water and albumin at set temp
at specific time interval, sample removed, disinfectant neutralised, determines viable count
what validation does the suspension test give
know viable count of innoculum, experimental conditions validation, neutraliser toxicity validation, disinfectant neutralisation validation
what qualatative test estimates bacteriostasis
minimum inhibitory concentration
estimation of bacteriostasis
how are minimum inhibitory concentrations tested
double dilutions of test agent prepared, innoculated with test organism, incubate overnight, score for growth, MIC is lowest conc with no growth
what is the disc susceptability test
agar spread with test organism, filter paper disc impregnates with known conc test agent placed on plate, zone of growth inhibition indicates antimicrobial activity, measure, compare to standards
how to evaluate antiseptics with time kill
for each microorganism and antimicrobial; dilute each test agent, innoculate with test organism, at designated time intervals remove sample/neutralise antimicrobial and determine viable count
what classes of agent are used as disinfectants
organic acids and esters, aliphatic alcohols, aldehydes, biguanides, halogens, hydrogen peroxide and peracetic acid, phenolics, surface acting agents
what are the advantages of using aliphatic alcohols
broad antimicrobial activity- active against bacteria including fungi, rapid kill, water soluble, relatively non-toxic, no residues
what are the disadvantages of using aliphatic alcohols
non sporicidal, isopropranolol not virucidal, poor penetration of organic matter, high dilution coefficient, flammable
what are examples of aliphatic alcohols
ethanol, isopropanol
what are examples of aldehydes
glutaraldehyde, formaldehyde
what are advantages of aldehydes
broad spectrum, sporicidal, rapid kill, not affected by organic matter
