Sterilization
Moist and dry heat, filtration, radiation, gases and validation with biological indicators.
Short notes and cheat sheetSubject guide
Microbiology MCQs for Pharmacy Exams
Sterilisation, antimicrobial resistance, microbial identification and immunology.
Pharmaceutical microbiology covers the microorganisms that cause disease and spoil medicines, and the methods used to control them. It features in Pharm-D exams, NTS screening tests and hospital pharmacist selections, where infection control and sterile products are daily concerns.
Sterilisation methods, aseptic technique and resistance mechanisms are the reliable scoring areas. These microbiology MCQs concentrate on the parts of the subject a pharmacist actually uses.
Topics covered
What Microbiology questions on PharmaPrep cover.
Antimicrobial Resistance
Beta-lactamases, efflux pumps, target modification and stewardship.
Short notes and cheat sheetMicrobial Culture and Identification
Gram staining, culture media and common pathogens.
Short notes and cheat sheetImmunology and Vaccines
Innate and adaptive immunity, vaccine types and cold chain.
Short notes and cheat sheetHigh-yield Microbiology topics
- Autoclave conditions and the biological indicator used to validate them
- Gram-positive versus gram-negative cell walls
- Mechanisms of antimicrobial resistance
- Live attenuated versus inactivated vaccines
- Sterilisation method for each type of product
Exams that test Microbiology
Sample Microbiology MCQs
Original practice questions with answers and explanations.
1The biological indicator used to validate steam sterilisation in an autoclave is spores of:
- AGeobacillus stearothermophilus
- BBacillus pumilus
- CEscherichia coli
- DStaphylococcus aureus
Show answer and explanation
Answer: A. Geobacillus stearothermophilus
Geobacillus stearothermophilus spores are highly resistant to moist heat, so their destruction confirms an effective steam cycle. Bacillus pumilus has been used for radiation sterilisation, and vegetative bacteria are far too easily killed to serve as indicators.
2Membrane filtration for sterilising heat-labile solutions typically uses a pore size of:
- A0.22 micrometres
- B5 micrometres
- C1 millimetre
- D0.45 millimetres
Show answer and explanation
Answer: A. 0.22 micrometres
A 0.22 µm (or 0.2 µm) membrane retains bacteria and is the standard for sterilising filtration of heat-sensitive solutions. Larger pore sizes remove particles but not bacteria.
3Gram-negative bacteria stain pink in Gram staining because they:
- AHave a thin peptidoglycan layer that loses the crystal violet complex
- BHave a thick peptidoglycan layer
- CLack a cell wall entirely
- DRetain the crystal violet-iodine complex
Show answer and explanation
Answer: A. Have a thin peptidoglycan layer that loses the crystal violet complex
The thin peptidoglycan layer of gram-negative bacteria does not retain the crystal violet-iodine complex after decolourisation, so they take up the safranin counterstain. Gram-positive bacteria have thick peptidoglycan and stay purple.
Microbiology FAQs
Which microbiology topics matter most for pharmacists?
Sterilisation and its validation, aseptic technique, antimicrobial resistance and vaccines are the most relevant and most frequently tested.
Is microbiology tested in hospital pharmacist tests?
Yes, especially infection control, sterile product preparation and antimicrobial stewardship.
Do the MCQs include immunology?
Yes. Basic immunology and vaccine types are included under this subject.