Lecture 13 Flashcards
What is sterilization?
killing of all living organisms
What is disinfection?
killing or removal of pathogens from inanimate objects
What is antisepsis?
killing or removal of pathogens from the surface of living tissues
What is sanitation?
reducing the microbial population to safe levels
What is degerming?
washing hands
What is the D-value?
decimal reduction time, the length of time it takes to kill 90% of microbial population
What are the physical methods of control?
heat, cool, pressure, desiccation, and radiation
What is more effective in killing cells: dry or moist heat?
moist
What is the steam autoclave?
a combination of high pressure and temperature; ex, canning
What is pasteurization?
uses a different combination of time and heat; HTST is used for milk
What is filtration?
micropore filters that remove microbial cells but not viruses from solutions, used for cells that cannot be heated
What are better penetrating power UV or Gamma rays?
Gamma rays
What resistants do bacteria develop towards disinfectants?
lipid envelop, biofilm, and efflux pumps
What is broad spectrum antibiotics?
effective against species
What are narrow spectrum antibiotics?
effective against few or single species
What are bactericidal antibiotics?
kill target organisms
What are bacteriostatic antibiotics?
they do not kill organisms but prevent growth
What is the problem with broad spectrum antibiotics?
they may kill helpful species and not drug-resistant pathogens
What antibacterial agents target the cell wall?
penicillin and vancomycin
What antibacterial agents target the plasma membrane?
polymyxins and lipopeptides
What antibacterial agents target the ribosomes?
aminoglycosides, tetracyclines, and chloramphenicol
What antibacterial agents target the DNA synthesis?
fluoroquiolones (drugs ending in floxacin)
What antibacterial agents target the metabolic pathways?
folic acid synthesis, mycolic acid synthesis
How does penicillin block cell wall synthesis?
binds to binding proteins and block chain elongation
How does vancomycin block cell wall synthesis?
blocks transpeptide bond formation
How do antibiotics target ribosomes?
inhibit transcription, RNA synthesis, and protein synthesis
What is the mode of action for cells that target the cell membrane?
extract LPS, membrane proteins, and phospholipids, poke holes in membrane
What is the mode of action for cells that target replication?
inhibit RNA polymerase blocking translation and fluoroquinolone block DNA replication
What is the mode of action for cells that target metabolism?
block synthesis of folic acid and block mycobacterial ATP synthase
