Foundations Revision Framework

Every organism, across Bacteriology, Virology, Mycology, and Parasitology, should be worked through using the same seven questions. This framework is the direct synthesis of subsections 1 through 19 above, and is the tool to apply when learning any new organism.

• Bacterium, virus, fungus, or parasite (protozoan, helminth, ectoparasite).
• Determines which broad structural and classification rules apply (subsections 1, 2).

• Cell wall (present or absent; peptidoglycan, chitin, or none; Gram positive or negative if bacterial).
• Genome (DNA or RNA if viral; ploidy and organisation if eukaryotic).
• Envelope (present or absent, if viral).
• Capsule (present or absent, antiphagocytic significance).
• Special structures (flagella, pili, spores, dimorphic switching, life cycle stages).
• Determines diagnostic appearance (Gram stain, microscopy) and antimicrobial target availability (subsections 3, 4, 5, 6, 7, 8).

• Reservoir (human, animal, environmental).
• Transmission route (direct: contact, sexual, droplet, vertical; indirect: fomite, food, water, airborne, vector).
• Portal of entry (respiratory, gastrointestinal, genitourinary, skin, parenteral, transplacental).
• Determines epidemiology, infection control precautions, and public health response (subsections 12, 13).

• Adhesion mechanism.
• Invasion capacity.
• Toxin production (exotoxin, endotoxin, or neither).
• Immune evasion strategy.
• Infectious dose.
• Determines the clinical syndrome produced and its severity (subsections 11, 16).

• Physical, mechanical, and chemical barriers encountered (skin, mucous membranes, mucociliary clearance, gastric acid, normal microbiota).
• Innate immune response engaged.
• Adaptive immune response engaged.
• Determines whether the organism is cleared, controlled, or established, and what happens when host defences are impaired (opportunistic infection) (subsections 9, 10, 12; full detail in Immunology for Microbiology).

• Microscopy (Gram stain, acid fast stain, wet preparation).
• Culture (media type required, growth characteristics, oxygen requirement).
• Antigen detection.
• Molecular testing (PCR and related methods).
• Serology, where relevant.
• Determines the correct specimen, the correct test, and how to interpret a positive or negative result (subsections 14, 18, 19; full detail in Diagnostic Microbiology).

• Antimicrobial agents active against the organism, and the mechanism of any resistance encountered.
• Sterilisation and disinfection measures effective against it (relevant to its structural resistance, for example endospore resistance to standard disinfectants).
• Infection prevention measures (hand hygiene, isolation precautions, PPE) matched to its transmission route.
• Vaccination, where available.
• Full detail in Antimicrobial Agents and Resistance and Sterilisation, Disinfection and Infection Prevention.

• These seven questions are not independent. Structure determines detection method. Transmission route determines control measures. Virulence mechanism determines clinical presentation, which in turn determines what specimen should be sent and what the laboratory result actually means once it comes back.
• When Bacteriology, Virology, Mycology, and Parasitology introduce a specific organism, work through these seven questions in order before moving to the next organism. This is the fastest route to genuine retention in microbiology, since it forces every new fact to be filed against a fixed, repeatable structure rather than memorised as an isolated detail.