Antisepsis/ Disinfection Flashcards
Micro Final Exam
How do you determine the effectiveness of Antiseptic and Disinfectant?
Phenol Coefficient: determines the agent’s ability to control microbes as a ratio of that of phenol. >1.0 means it is more effective than phenol
What methods of controlling microbes rely on moist heat?
Boiling, Autoclaving, Pasteurization, Ultra high temp. processing
Aseptic
an environment free of pathogenic contaminants
Decontamination
Disinfection
destruction of most microorganisms and viruses on nonliving tissue
Sterilization
destruction of all microorganisms and viruses on or in an object
Alcohols
Intermediate level disinfectant
Denature proteins and disrupt cytoplasmic membranes
Radiation:
Ionizing vs. Non-ionizing
Ionizing: wave lengths 40-390nm, denatures proteins, poorly penetrating, can sanitize air
Non-ionizing: Shorter wavelengths, denatures proteins, penetrates solid barriers
What microbial forms are less likely to be neutralized by boiling?
endospores, protozoan cyst, some viruses
What materials can be sterilized using membrane filtration?
food and drink that cannot tolerate heat
Pasteurization vs. ultra High Temp. Sterilization
Pasteurization: low temp. long time, high temp short time, does not kill all bacteria, shelf life is 2 weeks after
UHTS: 280 for 2-4 seconds, wipes out all bacteria, shelf life 6months at room temp unopened, tastes different
Broad vs. Narrow Spectrum
Broad: effective against a wide array of types (+-)
Narrow: effective against limited array of types (+)
How to test Antimicrobial effectiveness?
Diffusion susceptibility test (Zone of inhibition)
minimum inhibitory concentration test
How is resistance achieved against penicillin?
strengthening of the bacterial cell wall, or through selection of bacteria expressing mutant proteins capable of degrading penicillin
Mutation
Bacteria develops defense mechanisms against antibiotic
