General Microbiology & Sterilisation

Topics in this chapter

• Microbiology Foundations and Bacterial Structure
• Bacterial Growth and Growth Kinetics
• Culture Media and Preparation
• Sterilisation Methods and Validation
• Disinfection, Antisepsis and Infection Control
• Antimicrobial Susceptibility and Resistance

Practice questions

1. Question 1Q-9596D6

   A microbiology laboratory is processing heat-labile equipment, including plastic culture plates and certain disposable syringes. Which of the following sterilization methods is most appropriate for industrial sterilization of these pre-packaged items?

   1. A.Autoclaving at 121 degrees Celsius
   2. B.Gamma irradiation
   3. C.Inspissation
   4. D.Tyndallization
   See the answer and solution
2. Question 2Q-4A40EC

   Which of the following biological indicators is specifically used to monitor the efficacy of ethylene oxide (EtO) sterilization?

   1. A.Geobacillus stearothermophilus
   2. B.Bacillus atrophaeus
   3. C.Bacillus pumilus
   4. D.Pseudomonas aeruginosa
   See the answer and solution
3. Question 3Q-C260CF

   A researcher wishes to determine the lowest concentration of an antimicrobial agent that completely inhibits visible growth of a bacterium after overnight incubation. What is this parameter called?

   1. A.Minimum Bactericidal Concentration (MBC)
   2. B.Minimum Inhibitory Concentration (MIC)
   3. C.D-value
   4. D.Z-value
   See the answer and solution
4. Question 4Q-00E4FE

   During the growth curve of a bacterial batch culture, the rate of cell division equals the rate of cell death during which phase?

   1. A.Lag phase
   2. B.Log (exponential) phase
   3. C.Stationary phase
   4. D.Decline (death) phase
   See the answer and solution
5. Question 5Q-81BCE1

   What is the primary mechanism of action of alcohol (such as 70 percent isopropyl alcohol) as an antiseptic and disinfectant?

   1. A.Alkylation of nucleic acids
   2. B.Denaturation of proteins and disruption of cell membranes
   3. C.Inhibition of cell wall synthesis by binding to transpeptidases
   4. D.Oxidation of essential sulfhydryl groups
   See the answer and solution