controlling microbial growth Flashcards
Antisepsis
reduces amount on living tissue
degerm
remove germs by mechanical means
disinfection
no microbes non living tissue
sanitization
remove to level of health standards
sterilize
destroy all in or on object
action of antimicrobial agens
destroy cell wall or nucleic acid interfere with or denature proteins
Kelsey sykes capacity test
Suspensions added to dilution for varying times. Can determined time required for disinfection
In use test
swabs taken before and after application, innoculated incubated observed for growth.
heat kills how?
denatures proteins, disrupts cell wall and structure function nucleic acids
thermal death point
is lowest temp to kill all cells broth in 10 minutes
thermal death time
time to kill on microbes in a certain volume at certain temp
Pastuerization
remove most pathogenic bacteria in food or dink. Thermophiles can survive.
Psychrophilic microbes
can grow in fridge. ie yersina listeria
Phenol
intermediate denatures proteins disrupts cell membranes, active for long time.
Lysol triclosan bispehnolics
Alcohol
denatures proteins, removes well. Evaporates, low contact time.
Halogens
damage proteins denature.
Iodine bleach bromine.
oxidizing agents
peroxide ozone peracetic acid. Oxidizes microbial enzymes.
Surfactants
soaps good degerming, not antimicribal.
Detergents quats - disrupt cell membranes.
Heavy metals
fungi and bacteriostatic
beta lactam structure
square with nitrogen. anything with illin penicillin methicilin cephalosporin monobactam
beta lactam effective against
synthetics broader range. more stable more absorbed less degraded. simplest only effective against g+.
vanomycin and cycloserine
interfere with nam subunits in G+ (beta lactam)
bacitracin
blocks secretion of nag and nam
isozianid and ethambutamol
disrupt mycolic acid formation in mycobacterium.
aminoglycosides mechanism
some like streptomycin cause change in 30S shape so mRNA misread. Others like tetracycline block A (50s) site docking.
chloramphenicol
blocks peptide bond formation
lincosamides or macrolides
bind 50s, block mRNA movement through ribosome
azoles and allylamines
inhibit fungal cell wall synthesis
polymyxin
disrupts gram negative cytoplasmic membrane ie pseudomonas
atavaquone
interferes with electron transport in prozoa (malaria) and fungi.
niclosamide
disrupt oxidative phosphorylation in worms and protozoa
sulfanilamide
normally paba-.thf-DNA / RNA synthesis. sulfanilimide irrversibly inactivates folic acid synthesis from paba.
quinolones and flouronquinolones
act against DNA gyrase, like ciprofloxacin.
Mic
add drugs at diff dilutions to test tubes see which dilution causes no growth
estrip
see what concentration kills on plate. size cann change.
minimum bacteriacidal concentration (MBC)
broth test, plate. see if colonies are there. no colonies means concentration killed not inhibited growth
7 mechanisms antimicrobial resistance
pump out, alter active site, drop metabolic pathway, produce degradation enzyme, biofilm, produce protein like MFP in mycobacterium to alter target protein
tetrad
square one level
sarcinae
cube multiple leves.
