24: Disinfectants & Antiseptics Flashcards
Variety of chemicals available for controlling the growth of microbes.
Antimicrobial agents
Chemical agents used on inanimate objects to lower the level of microbes on their surfaces.
Disinfectants
Chemicals used on living tissue to decrease the number of microbes.
Antiseptics
Results in bacterial death
Bactericidal
Temporary inhibition of bacterial growth
Bacteriostatic
No single chemical is best to use in all situations variables to consider include:
Type of organism, environmental conditions, pH, solubility, toxicity, organic material present, and cost
Important criteria in evaluating effectiveness of antimicrobial agents:
Concentration, length of contact, bactericidal/bacteriostatic
Time it takes to kill 90% of the test microbial population
Decimal Reduction Time (DRT)
What is the standard method for measuring effectiveness of a chemical agent?
American Official Analytical Chemist’s use-dilution test
The use-dilution test involves:
1) Metal rings dipped into cultures of bacteria grown is liquid media; removed and dried
2) Rings placed in solution of disinfectant at recommended concentration for 10 min. @ 20 degrees C
3) Rings transferred to nutrient medium to permit growth of surviving bacteria
4) Effectiveness determined by amount of resulting growth
The use-dilution test is limited to _____ compounds and can’t be used to evaluate _____ compounds.
bactericidal, bacteriostatic
