Bacterial Pathogenesis & Virulence Factors

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1. Which of the following helps bacteria invade host tissues?

A. Exotoxins B. Capsule polysaccharide C. Flagella-mediated motility D. Quorum sensing molecules

2. Lipopolysaccharide (LPS) primarily acts as:

A. Adhesion molecule B. Endotoxin C. Nutrient scavenger D. DNA-protective coat

3. Which secretion system injects effectors directly into host cells?

A. Type I secretion system B. Type III secretion system C. Sec pathway D. Type IV pilus

4. The bacterial capsule contributes to virulence by:

A. Preventing phagocytosis B. Increasing metabolic rate C. Delivering toxins D. Acting as an antibiotic

5. Which enzyme helps bacteria spread through host tissues?

A. Hyaluronidase B. Catalase C. Reverse transcriptase D. DNA gyrase

6. Siderophores are virulence factors because they:

A. Form biofilms B. Bind and sequester iron C. Lyse host cells D. Act as superantigens

7. Which statement about exotoxins is TRUE?

A. Only in Gram-negative bacteria B. Structural wall components C. Secreted proteins with specific targets D. Never systemic

8. Biofilms help bacteria survive by:

A. Increasing mutation rate B. Protecting from antibiotics and immunity C. Accelerating nutrient uptake D. Preventing gene transfer

9. Changing surface antigens to avoid immunity is called:

A. Antigenic variation B. Detoxification C. Binary fission D. Phage conversion

10. A superantigen is:

A. Ion channel B. Enzyme that degrades antibiotics C. Activates many T-cells nonspecifically D. Transcription factor

11. Which factor allows bacteria to attach to host cells?

A. Adhesins B. Proteases C. Ribosomes D. Porins

12. Which bacterial product digests IgA?

A. Beta-lactamase B. DNAse C. Catalase D. IgA protease

13. Which describes quorum sensing?

A. Glucose metabolism B. Bacterial communication using signaling molecules C. Cell wall formation D. DNA repair

14. Which toxin increases cAMP levels?

A. Cholera toxin B. Tetanus toxin C. Alpha toxin D. Shiga toxin

15. Which toxin inhibits protein synthesis by targeting ribosomes?

A. Shiga toxin B. Botulinum toxin C. Cholera toxin D. Hemolysin

16. Which virulence factor prevents complement activation?

A. Pili B. Flagella C. Capsule D. Lipase

17. Which bacteria use type IV pili for twitching motility?

A. Staphylococcus B. Streptococcus C. Pseudomonas D. Bacillus

18. Which is an example of an AB toxin?

A. LPS B. Diphtheria toxin C. Teichoic acid D. Peptidoglycan

19. Which describes endotoxin?

A. Capsule B. Secreted polypeptide C. Enzyme D. Lipid A component of LPS

20. Which factor enables intracellular survival?

A. Inhibition of phagolysosome fusion B. Biofilm formation C. Flagella D. Pili

21. Which structure helps Helicobacter pylori survive stomach acid?

A. Endotoxin B. Hyaluronidase C. Protease D. Urease

22. Which organism uses antigenic shift/variation?

A. Staphylococcus aureus B. Neisseria gonorrhoeae C. Bacillus anthracis D. Clostridium botulinum

23. Which enzyme breaks down blood clots?

A. Lecithinase B. Catalase C. Beta-lactamase D. Streptokinase

24. Which factor triggers septic shock?

A. Flagella B. Endotoxin (LPS) C. Pili D. Teichoic acids

25. Which bacteria use type VI secretion?

A. Staphylococcus epidermidis B. Enterococcus C. Streptococcus pyogenes D. Vibrio cholerae

26. Which toxin blocks neurotransmitter release?

A. Cholera toxin B. Shiga toxin C. Botulinum toxin D. Alpha toxin

27. Which virulence factor is required for biofilm matrix?

A. Extracellular polysaccharide (EPS) B. Flagellin C. LPS D. Porins

28. Which organism produces the M protein?

A. Neisseria meningitidis B. E. coli C. Bacillus cereus D. Streptococcus pyogenes

29. What does coagulase do?

A. Breaks down clots B. Clots plasma to evade immunity C. Degrades IgA D. Damages membranes

30. Which factor allows survival inside macrophages?

A. Pili B. Hyaluronidase C. Prevention of oxidative burst D. Hemolysin