Lecture 6: Control of Microorganisms in the Environment

Question 1

Biocide (4 types)

Answer 1

Antimicrobial agents that control microorganisms.
-Physical, chemical, mechanical or biological.

Question 2

Sterilization

Answer 2

process by which all living cells, spores, and acellular entities are destroyed or removed from an object.
-If achieved by a chemical agent its called a sterilant.

Question 3

Disinfection

Answer 3

killing, inhibition, or removal of disease-causing microorganisms.
-Does not always sterilize as spores or a few organisms can remain.
-Disinfectants—agents, usually chemical, used for disinfection, usually used on inanimate objects.

Question 4

Sanitization

Answer 4

reduction of microbial population to levels deemed safe by public health standards.

Question 5

Antisepsis

Answer 5

destruction of microbes on living tissue, prevention of sepsis
* Antiseptics—chemical agents applied to tissue to kill or inhibit growth of pathogen, not as toxic as disinfectants.

Question 6

Chemotherapy (two types of agents)

Answer 6

generic term that describes application of chemicals to kill microorganisms.
- Cidal agents and Static agents

Question 7

Cidal agents

Answer 7

-They kill.
- Include bactericides, fungicides, and viricides

Question 8

Static agents

Answer 8

-They inhibit growth, if removed growth resumes.
- Include bacteriostatic and fungistatic

Question 9

Four resistance mechanisms to biocides

Answer 9

1. Efflux pumps: pump out antimicrobial agents
   - resistance mechanism to biocides
2. Alter membrane permeability: prevent entry of agents.
3. Modify the target: Mutation of bacterial DNA, no longer recognized by biocide.
4. Specific resistance genes: In plasmids, transferred to other cells.

Question 10

Alter