Microbiology
Core framework
Microbiology questions test organism identification and the host response. Master bacterial classification and virulence factors, the classic clinical syndromes produced by each organism, sterilization and disinfection principles, and the basics of immunology including hypersensitivity types and vaccine types. Know which organism is expected for a given site, age group, and exposure history.
Concepts you must own
Gram stain and morphology as a first discriminator. Toxin-mediated versus invasive disease. The hypersensitivity classification with one example each. The difference between live attenuated and inactivated vaccines. Standard, contact, and airborne precautions.
Traps
- Colonizer versus pathogen: the same organism may be normal flora at one site and pathogenic at another.
- Toxin-mediated disease may occur without live organisms at the site of symptoms.
- Hypersensitivity type: match the mechanism (IgE, cytotoxic, immune complex, cell-mediated) before choosing the example.
Worked rule of thumb
For any infectious-disease stem, ask three questions in order: what is the site, what is the host (age, immune status, exposure), and what is the stain or morphology? These three narrow the organism list to a handful, and the syndrome then selects the answer.