Microbiology - Domain Overview
Microbiology (BSMIC) accounts for approximately 4.0% of the CST exam (6 of 150 scored items). It covers pathogenic microorganisms, the chain of infection, surgical site infection prevention, antimicrobial agents, aseptic technique principles, and bioburden management.
What This Domain Covers
- Categories of pathogenic organisms - bacteria, viruses, fungi, and prions - and their relevance to sterilization requirements.
- The chain of infection framework and how specific practices interrupt each link.
- Resident vs. transient skin flora and their relevance to the surgical scrub.
- Antisepsis vs. disinfection terminology and application.
- Standard precautions and personal protective equipment.
Why BSMIC Matters in Practice
Although this domain carries a small direct question count, its concepts form the scientific foundation for infection prevention practices tested throughout INTRA, EQSM, and PREOP content. A strong grasp of microbiology fundamentals reinforces your understanding across the entire exam, not just this single domain.
Frequently Asked Questions
What percentage of the CST exam is BSMIC?
Microbiology makes up approximately 4.0% of the exam, or 6 of the 150 scored questions.
How does the chain of infection get tested?
Questions typically describe a specific practice or intervention and ask which link of the chain it interrupts, rather than simply asking you to list the six links.
Why do spores matter so much in this domain?
Spore-forming organisms resist standard disinfection, which is exactly why critical items require true sterilization rather than high-level disinfection.
Explore the full BSMIC study suite: Glossary, Exam Tips, Exam Day Guide, and Common Mistakes.