Control of Microbial Growth

Schooling, instead of encouraging the asking of questions, too often discourages it Madeleine L’Engle
	Life in a drop of water

Who am I?:

I showed that B cell generate different antibody molecules by recombination bwteen multiple gene segements. I received the Noble Prize in Medicine in 1987

	Readings Control of Microbial Growth
	Baron Medical Microbiology chap 51 Control of viral infections and Disease		Brock 9th Ed Biology of Microorganisms Chapt 18 Microbial Growth Control
	Tortora: Microbiology An Introduction Chapt 7 Control of Microbial Growth		Jacquelyn Black 4th Ed Microbiology: Principles & Explorations Chap 12 Sterilization and Disinfection
Presentation	Slides	Web Animation	Download
Physical Sterilization Agents
Chemical Agents

SHORT ANSWER QUESTIONS

1. Describe the patterns of microbial death caused by treatments with microbial control agents
2. Describe with specific examples the effects of microbial control agents on cellular structures
3. Compare the effectiveness of moist heat and dry heat for controlling microbial growth
4. Construct a table that summarizaes the physical methods of microbial growth Include the method, the mechanisms of action and the preferrred use of each method
5. List factors related to effective disinfection
6. Explain how microbial growth is affected by the type of microbe and the envirnmental conditions include in your discussion the organism Pseudomonas, Mycobacterium and hepatitis virus.
7. Why is each of the following bacteria often resistant to disinfectants?

• Bacillus
• Mycobacterium
• Mycobacterium

8. A large hospital washes burn patients in a stainless steel tub. After each patient the tube is cleaned with a quat.. It was noticed that 14 of the 20 burn patients acquired Pseudomonas infections after being bathed. Provide an explanation for this high rate of infection.
9. List five factors to condiser before selecting a disinfectant
10. Construct a table that identifies the methods of action and the preferred uses of chemical disinfectants
11. Differentiate between halogens uses as antiseptics and as disinfectants
12. List the appropriate uses for surface- active agents
13. List the advantages of glutaraldehyde over other chemical disinfectants
14. Identify a method for sterilizing each of the following: plastic labware, vaccines, antibiotics, mattresses, surgical towels, microbiological loops, dairy utensils.
15. Differentiate between antimicrobials and antibiotics

Question:

The filter paper method was used to evaluate three disinfectants.; the results were as follows

from the above results which disinfectant was the most effective? Explain

Can you determine from these results whether Brand X was bactericidal or bacteriostatic? Explain

Question :

The use dilution test was sued to evaluate two disinfectants against Salmonella choleraesuis.

The results were as follows:

Which disinfectant was the most effective? explain.

Which disinfectant should be used against Staphylococcus? Explain.

The following data were obtained from ause- dilution test comparing four disinfectants against Salmonella choleraesuis

Which disinfectant is the most effective? Explain.