Antibiotic Resistance Mechanisms

Antibiotic Resistance Mechanisms — 30 Question Quiz

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1. Which of the following best describes the mechanism of methicillin resistance in MRSA?

A. Overexpression of beta-lactamase B. Production of modified PBPs with low affinity for beta-lactams C. Efflux pump overactivation D. Target site methylation

2. The enzyme New Delhi metallo-β-lactamase (NDM-1) primarily confers resistance to:

A. Cephalosporins only B. Carbapenems C. Glycopeptides D. Lipopeptides

3. Which genetic element is MOST responsible for rapid horizontal transfer of antibiotic-resistance genes among Gram-negative bacteria?

A. Transposon B. Plasmid C. Phage DNA D. Insertion sequence

4. Vancomycin resistance in Enterococcus (VRE) is primarily due to:

A. Substitution of D-Ala–D-Ala with D-Ala–D-Lac B. Beta-lactamase production C. Altered DNA gyrase D. Increased biofilm formation

5. Which enzyme modifies aminoglycosides, reducing drug binding to the ribosome?

A. Acetyltransferase B. Carbapenemase C. Peptidyl transferase D. Penicillinase

6. Tet(A) and Tet(K) resistance determinants mainly function through:

A. Target protection B. Enzymatic drug inactivation C. Efflux pumps D. Biofilm formation

7. Which mutation confers fluoroquinolone resistance in many bacteria?

A. vanA gene B. mecA gene C. gyrA mutation D. blaZ gene

8. ESBLs (extended-spectrum beta-lactamases) hydrolyze all of the following EXCEPT:

A. Penicillins B. First-generation cephalosporins C. Carbapenems D. Third-generation cephalosporins

9. MLSB resistance (macrolide-lincosamide-streptogramin B) occurs due to:

A. Enzymatic acetylation of macrolides B. 23S rRNA methylation C. Porin loss D. Alteration of LPS

10. Which resistance mechanism is MOST associated with Pseudomonas aeruginosa’s multidrug profile?

A. Absence of outer membrane B. High expression of efflux pumps (e.g., MexAB-OprM) C. Beta-lactamase deficiency D. Ribosomal protection proteins

11. Ribosomal methyltransferase ErmB contributes to resistance by:

A. Burning ribosomal RNA B. Blocking tRNA binding C. Preventing macrolide binding D. Enhancing ribosome recycling

12. Which antibiotic class is MOST affected by porin loss in Gram-negative bacteria?

A. Macrolides B. Aminoglycosides C. Beta-lactams D. Lipopeptides

13. Which of the following is a plasmid-mediated quinolone resistance mechanism?

A. tetM B. qnr proteins C. blaCTX-M D. vanB

14. The mcr-1 gene confers resistance to:

A. Tetracycline B. Colistin C. Carbapenems D. Linezolid

15. Which mechanism confers resistance to linezolid?

A. 23S rRNA mutation B. Efflux pump activation C. Beta-lactamase production D. PBP alteration

16. Which enzyme inactivates chloramphenicol?

A. Chloramphenicol acetyltransferase B. Beta-lactamase C. Aminoglycoside phosphotransferase D. DNA methylase

17. Which resistance mechanism allows Mycobacterium tuberculosis to resist isoniazid?

A. katG mutation B. gyrA mutation C. rpoB mutation D. mecA expression

18. A bacteria with efflux-mediated tetracycline resistance will most likely resist:

A. Tigecycline B. Minocycline C. Doxycycline D. Tetracycline only

19. Carbapenem resistance in Klebsiella pneumoniae is often due to:

A. Altered porin channels plus ESBL or AmpC production B. Ribosomal protection proteins C. D-Ala–D-Lac modification D. LPS loss

20. Which gene cluster confers vancomycin resistance in Enterococci?

A. mecA B. blaKPC C. vanA/vanB D. qnrB

21. Aminoglycoside resistance due to ribosomal alteration occurs primarily by mutation in:

A. 16S rRNA B. 23S rRNA C. PBP2a D. RNA polymerase

22. Macrolide resistance can result from efflux pumps encoded by:

A. mef genes B. blaTEM C. vanC D. ermC

23. A Gram-negative organism lacking OprD porin is resistant to:

A. Aztreonam B. Imipenem C. Vancomycin D. Ciprofloxacin

24. The resistance mechanism to daptomycin often involves:

A. Increased membrane charge (via mprF mutation) B. Altered porins C. Efflux pumps D. Beta-lactamase production

25. Which resistance mechanism is found in Mycoplasma pneumoniae?

A. Porin loss B. Beta-lactamase C. Absence of cell wall (intrinsic resistance to beta-lactams) D. Modified LPS

26. A Klebsiella isolate resistant to colistin but sensitive to carbapenems most likely carries:

A. blaNDM B. mcr-1 C. mecA D. ermB

27. Resistance to TMP-SMX can involve overproduction of:

A. Dihydrofolate reductase B. Beta-lactamase C. 23S rRNA D. DNA gyrase

28. Biofilm-associated resistance is mainly due to:

A. Increased mutation rate B. Poor antibiotic penetration and persister cells C. Enhanced beta-lactamase activity only D. Increased porin numbers

29. Which mechanism allows resistance to rifampin?

A. rpoB gene mutation B. gyrB mutation C. mecA gene insertion D. 16S rRNA methylation

30. Which of the following molecules is associated with target protection as a resistance strategy?

A. Qnr proteins B. Beta-lactamase C. MCR-1 D. Erm methyltransferase