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Microbial Control and Chemotherapy
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Microbial Control and Chemotherapy
Microbial Control and Chemotherapy
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1
Question
What is the purpose of controlling microorganisms?
Page 1
Answer
Prevents transmission of diseases and infection, stops decomposition and spoilage, prevents unwanted microbial contamination.
2
Question
What methods do physical agents use for microbial control?
Page 1
Answer
High or low temperature, desiccation, osmotic pressure, radiation, and filtration.
3
Question
What does control by chemical agents refer to?
Page 1
Answer
Use of disinfectants, antiseptics, antibiotics, and chemotherapeutic antimicrobial chemicals.
4
Question
What is the focus of chemical control in this unit?
Page 1
Answer
Antibiotics and chemotherapeutic antimicrobial chemicals used in treating bacterial infections.
5
Question
What is the basis of chemotherapeutic control of bacteria?
Page 1
Answer
Selective toxicity.
6
Question
What does selective toxicity mean?
Page 1
Answer
Chemical inhibits or kills intended pathogen without seriously harming the host.
7
Question
What characterizes a broad spectrum agent?
Page 1
Answer
Generally effective against a variety of Gram-positive and Gram-negative bacteria.
8
Question
What defines a narrow spectrum agent?
Page 1
Answer
Generally works against just Gram-positives, Gram-negatives, or only a few bacteria.
9
Question
How does a cidal agent differ from a static agent?
Page 1
Answer
Cidal agent kills the organism. Static agent inhibits growth long enough for body defenses to remove it.
10
Question
What are the two categories of antimicrobial chemotherapeutic agents?
Page 1
Answer
Antibiotics and synthetic chemotherapeutic drugs.
11
Question
What is an antibiotic?
Page 1
Answer
Metabolic product of one microorganism that inhibits or kills other microorganisms.
12
Question
Why do bacteria produce antibiotics in large amounts?
Page 1
Answer
Used as a weapon to inhibit or kill other microbes nearby and reduce food competition.
13
Question
What role do sublethal antibiotics play in interspecies quorum sensing?
Page 2
Answer
Enable different bacteria to form a common biofilm where metabolic products serve as substrates. All protected in biofilm.
14
Question
How can sublethal antibiotics affect bacterial motility?
Page 2
Answer
Function as interspecies quorum sensing molecules to make some bacteria motile and swim away, reducing food competition.
15
Question
What cues from antibiotic action trigger biofilm formation?
Page 2
Answer
Degradation products of bacterial cell walls or DNA act as signals for other bacteria to produce protective biofilm.
16
Question
How do sublethal antibiotics trigger intraspecies quorum sensing?
Page 2
Answer
Low concentrations trigger production of quorum sensing molecules that induce population to form protective biofilm against higher antibiotic levels.
17
Question
What is sterilization?
Page 2
Answer
Process of destroying all living organisms and viruses. Sterile object free of all life forms including bacterial endospores and viruses.
18
Question
What is disinfection?
Page 2
Answer
Elimination of microorganisms, but not necessarily endospores, from inanimate objects or surfaces.
19
Question
Define decontamination.
Page 2
Answer
Treatment of an object or inanimate surface to make it safe to handle.
20
Question
What is a disinfectant?
Page 2
Answer
Agent used to disinfect inanimate objects but generally too toxic to use on human tissues.
21
Question
What is an antiseptic?
Page 2
Answer
Agent that kills or inhibits growth of microbes but safe to use on human tissue.
22
Question
Define sanitizer.
Page 2
Answer
Agent that reduces microbial numbers to a safe level.
23
Question
What are synthetic chemotherapeutic drugs?
Page 3
Answer
Antimicrobial drugs synthesized by chemical procedures in the laboratory.
24
Question
What does a cidal agent do to microorganisms?
Page 3
Answer
Kills microorganisms.
25
Question
What does a static agent do to microorganisms?
Page 3
Answer
Inhibits the growth of microorganisms.
26
Question
How does moist heat control microbial growth?
Page 3
Answer
Denatures proteins and enzymes, disrupts cell membranes.
27
Question
What is the effect of dry heat on microbes?
Page 3
Answer
Oxidizes cell components and causes protein denaturation.
28
Question
What does refrigeration do to bacterial metabolism?
Page 3
Answer
Slows metabolism – bacteriostatic, not bactericidal.
29
Question
How does deep-freezing or lyophilization affect microbes?
Page 3
Answer
Halts metabolism by dehydration and ice crystal formation.
30
Question
Why is filtration ideal for certain solutions?
Page 3
Answer
Physically removes microbes from air or liquids with no heat, ideal for heat-sensitive solutions like antibiotics and vaccines.