A comprehensive resource on pathogenic bacteria, viruses, fungi, and parasites — from culture media and staining to clinical laboratory diagnosis, and self-assessment with interactive MCQs.
Normal flora are the microbes that live on and inside us. Where they live, where the body stays sterile, how we first acquire them, how they protect us, and why they sometimes cause infection.
How bacteria cause disease, step by step: pathogenicity versus virulence, infectious dose, entry, adherence, colonization, invasion, toxins, and how pathogens evade the immune system.
Bacterial virulence factors grouped by the job they do: adhering, invading, resisting phagocytosis, damaging tissue, and persisting. How adhesins, enzymes, capsules, toxins, and biofilms work.
The chain of infection explained: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host, with how each infection-control measure breaks a link.
The types and patterns of infection explained through four questions: how widespread, how many microbes, what time-course, and where acquired, plus carrier states and their clinical importance.
Which genital specimen to collect for which infection, the male and female differences, why gonococcus needs bedside inoculation and never refrigeration, when a swab beats urine, and how NAAT changed specimen choice.
Why tissue is the reference-standard specimen for deep infection, why the microbiology portion must be split off before formalin or decalcification, when to mince instead of grind, and how one small biopsy is divided across bacterial, AFB, fungal, and histology testing.
Why you swab both eyes even when one looks normal, how the specimen changes from conjunctivitis to a corneal ulcer, why eye samples are inoculated at the bedside, and when to think fungus or Acanthamoeba.
Why an open-wound swab is only as good as the technique, how the Levine method samples deep fluid instead of surface flora, how to tell colonization from infection, and when tissue biopsy or aspirate is the right specimen instead.
How to collect and split pleural, ascitic, pericardial, and synovial fluid across the right containers, why some goes into a blood culture bottle, which anticoagulant not to use for joint fluid, and why these fluids are never refrigerated.
Why an ear-canal swab answers otitis externa but not otitis media, how to sample a discharging ear without collecting canal flora, when tympanocentesis is needed, and why acute otitis media is usually not cultured.
How to take a throat swab that actually samples the tonsils and posterior pharynx, why the tongue and cheeks must be avoided, which test needs which swab, why children need a backup culture, and how to transport it.
Cytomegalovirus: the commonest congenital infection and leading non-genetic cause of childhood deafness. Owl's-eye inclusions, pp65, and primary-infection risk.
TORCH panel test explained: what the acronym covers, why IgM and IgG mean different things in mother and newborn, and how infection timing decides fetal risk.
