Essential Microbiology Concepts and Principles

Posted on Jun 19, 2026 in Microbiology

Essential Microbiology and Immunology Concepts

  • 1. The term LD50 refers to: The dose of a pathogen required to kill 50% of a healthy community.
  • 2. Naturally acquired immunity: Antibody immunity is transferred passively between individuals (e.g., pregnancy and breastfeeding).
  • 3. Antibiotic resistance: Semisynthetic drugs are modifications of parent molecules designed to improve efficacy against new resistances.
  • 4. Herd immunity: Immunity generated in a fraction of the community that protects the entire population.
  • 5. Microbiology concept of a vector: Organisms capable of carrying and spreading an infectious pathogen to a new host.
  • 6. Baltimore viral classification: Based on genome type.
  • 7. Antimicrobial agents: All listed criteria are correct.
  • 8. E. coli grouping categories: All statements are true.
  • 9. Modern microbiology: There is an increasing use of modern technologies to solve both traditional and emerging problems.
  • 10. Influenza serotype changes: Antigenic shift.
  • 11. Seminar expositions: All provided options are correct.
  • 12. Immune system characteristics: The capacity to distinguish between self and non-self.
  • 13. Mycobacterium tuberculosis: All options are correct.
  • 14. Human microbiome relation: Multidirectional and complex.
  • 15. Antibiotic susceptibility testing: Kirby-Bauer method.
  • 16. Non-specific immune response: Cells and mechanisms providing the first line of innate immune defense.
  • 17. ssRNA- virus infectivity: The naked genome of an antisense ssRNA virus is never infective.
  • 18. Koch’s postulates: The putative pathogen must be isolated from individuals suffering from the disease and not from healthy ones.
  • 19. Prion diseases: Bovine Spongiform Encephalopathy and Creutzfeldt-Jakob disease are caused by prions, which are abnormally folded proteins.
  • 20. Bacterial virulence: Species B is more virulent than species A if it requires fewer cells to produce disease.
  • 21. Viral infection destinations: All options are true.
  • 22. Non-enveloped viruses: Viruses that do not possess a lipid bilayer are called naked.
  • 23. Viral chemical composition: Nucleic acids and proteins.
  • 24. Virulence factor: Mechanisms and molecules that allow a pathogen to evade immune defenses and produce disease.
  • 25. Innate vs. acquired immunity: None of the provided statements represent the characteristics of both immunities.
  • 26. Minimum Inhibitory Concentration (MIC): The lowest concentration of a substance that prevents visible growth of a pathogen after overnight incubation.
  • 27. Vaccine definition: A combination of one or more antigens that induces long-term protective immunity in the host.
  • 28. Immune evasion: The capability of microbes or viruses to avoid the host immune system allows them to survive within the host.
  • 29. Neisseria meningitidis: The main pathogenic mechanism is the crossing of the blood-brain barrier.
  • 30. Infectious disease process: There is a list of characteristic signs and symptoms that alert to the presence of disease.