Chapter 7 - Control of Microbial Growth Flashcards
Sterilization
removal of all microbial life (includes endospores!)
Commercial Sterilization
killing C. botulinum endospores before being placed on grocery shelves
Disinfection
removal of vegetative/non-endospore forming pathogens
Antisepsis
destruction of vegetative pathogens or living tissue
Degerming
removal of microbes from a limited area (usually skin)
Sanitization
lowers the microbial count on eating and drinking utensils
Ignaz Semmelweis
hand-washing
Joseph Lister
aseptic surgery-disinfectant
Mycobacteria have what kind of cell wall?
waxy and lipid
What part of the protozoa are resistant to chemical disinfection?
cyst
Gram ____ bacteria are more resistant.
negative
_____ are resistant to normal autoclaving and disinfection.
prions
What are 5 factors that influence the effectiveness of antimicrobials?
1) number of microbes
2) certain characteristics
3) environmental conditions
4) time of exposure
5) action of antimicrobial
What are 2 actions of antimicrobials?
1) changing of the permeability of the plasma membrane
2) damaging the protein/nucleic acid
Prions
infections proteins
More resistant microbes include
prions, endospores, mycobacteria, cysts of protozoa, vegetative protozoa
Less resistant microbes include
viruses with lipid envelopes, gram-positive bacteria, viruses without envelopes, fungi, gram-negative bacteria
Autoclave
sterilization using moist heat (higher than boiling point) in the form of steam by autoclaving at 121 degrees at 15 psi for 15 minutes
*preferred form of sterilization, its moist heat denatures proteins
Boiling
sterilization that kills most vegetative pathogens, viruses, and fungi along with their spores (most of the time)
Direct Flaming and Incinerators
sterilization by dry heat which kills by oxidation (inoculating loop)
Hot Oven
sterilization by dry heat which sterilized metal, glass, and plastic items (heat-sensitive items)
Ethylene Oxide
sterilization of culture media (virology), vaccines, IVs/antibiotics, solutions, and hospital equipment