Key Words Virulence/sterli/antimicrobial Flashcards
Cleaning
Physical removal of contamination using DETERGENTS
Disinfection
Reduce/Removal of microbial contamination using ANTIMICROBIALS
Bacteriostatic
DOESNT reduce bacteria number
Bacteriocidal
REDUCES cell number by LYSIS
Antiseptic
Kills on external surfaces of BODY
Preservative
Prevents decomposing produce such as food by inhibiting growth preventing MICROBIAL SPOILAGE
Kelsey Sykes Test
TRIPLE CHALLENGE test to determine concentration of disinfectant thats effective in dirty conditions
MIC
Lowest concentration that inhibits growth of microbes
Varies with different strains
MHT
Lowest concentration which is TOXIC to the body
Therapeutic range
Difference between the MHT-MIC
Selective toxicity
MIC
Sterlization
Biocidal agent / Physical process to remove ALL MICROORGANISMS
Has to be ABSOLUTE (be sterile or not)
Red Heat
Bunsen burners
Moist heat
Biocidal agent
134 3mins
Pressure / steam
Dry heat
Oxidative Process
160-180 2hrs
Hot air / fans
Gaseous Exchange
Formaldehyde
70 2hrs
Paper /cotton fabric
Filtration
Sterilisation by REMOVAL
HEPA filters for ROOMS
Bioburden
Concentration of microorganisms in a MATERIAL
Terminal Sterlisation
Broths / Pipette tips
Asceptic Processing
Pharmaceutical products
Gentamicin
Narrow TR
Pseudomonas aeruginosa
MIC - 1ug/ml
MHT - 10ug/ml
Benzyl penicillin
Large TR
Staph.aureus
MIC-0.02ug/ml
MHT-very very high
Name 4 mechanisms of selective toxicity
Inhibit
Peptidoglycan synthesis-Penicillin
Tetrahydroflorate-sulphonamides
70s - tetracyclines
DNA synthesis - quinolones
Microbiostatic
Inhibit growth
Relies on host to kill
Tetracyclines
Micro biocidal
Microbes killed
Penicillin
Linear graph of %strains inhibited to concentration of antibiotic
E.coli + benzyl penicillin
High variation
Staph aureus and Benzyl Penicillin
Low variation
MIC examples (2) using benzyl penicillin
Staph aureus - 0.02ug/ml
E.coli - 50ug/ml
The lower the MIC?
More active the molecule
For effective concentration of an antibiotic to work, what must occur?
Concentration administered must be HIGHER than MIC
Name 3 factors which can affect the effective concentration of a drug
Route of administration
Distribution around body tissues
Plasma proteins
How does a microorganism pick up different resistance
Conjugation (mixing genome)
Transformation (extra.DNA)
Transduction (bacteriophage)
Mutation (random)
Why is resistance a concern
Treatment failure
Increased mortality
Selection pressure = gonnarea resistance to 15 antibiotics
D value
Resistance of an organism
Time taken to achieve a 90% reduction in viable cells