Antimicrobials

Topics in this chapter

• Antimicrobial Mechanisms and Pharmacodynamics
• Cell Wall and Protein Synthesis Inhibitors
• DNA and Folate Synthesis Inhibitors
• Antifungal and Azole Therapy
• Tuberculosis Antimicrobial Therapy
• Antimicrobial Adverse Effects and Toxicity
• Antimicrobial Pregnancy Safety
• Antimicrobial Combination Synergy

Practice questions

1. Question 1Q-B456FB

   A 32-year-old male is diagnosed with pulmonary tuberculosis and is started on a standard four-drug regimen including isoniazid, rifampin, pyrazinamide, and ethambutol. Two weeks later, he complains of tingling and numbness in his hands and feet. Which of the following mechanisms best explains this adverse effect?

   1. A.Competitive inhibition of folate synthesis in bacterial cell walls
   2. B.Inhibition of mycolic acid synthesis by forming a complex with pyridoxine phosphokinase
   3. C.Chelation of divalent cations leading to peripheral nerve demyelination
   4. D.Direct antagonism of vitamin B6 by increasing its renal excretion and inhibiting pyridoxal kinase
   See the answer and solution
2. Question 2Q-38D174

   A 45-year-old female presents with acute pyelonephritis. Urine culture grows Escherichia coli resistant to multiple drugs. She is prescribed a fluoroquinolone. Which of the following is the primary intracellular target of fluoroquinolones in gram-negative bacteria?

   1. A.DNA gyrase (topoisomerase II) and topoisomerase IV
   2. B.RNA polymerase beta-subunit
   3. C.30S ribosomal subunit
   4. D.PBP2a (Penicillin-binding protein 2a)
   See the answer and solution
3. Question 3Q-93E00C

   A patient with severe hospital-acquired pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA) is treated with vancomycin. Therapeutic drug monitoring is essential because vancomycin toxicity primarily manifests as:

   1. A.Aplastic anemia and gray baby syndrome
   2. B.Nephrotoxicity and ototoxicity
   3. C.Disulfiram-like reaction and severe hypoglycemia
   4. D.Pulmonary fibrosis and optic neuritis
   See the answer and solution
4. Question 4Q-EA44CD

   A 60-year-old man undergoing treatment for infective endocarditis develops high-pitched tinnitus and progressive sensorineural hearing loss. Which of the following drugs is most likely responsible for this irreversible adverse effect?

   1. A.Vancomycin
   2. B.Gentamicin
   3. C.Ciprofloxacin
   4. D.Linezolid
   See the answer and solution
5. Question 5Q-5C09C5

   Which of the following anti-tubercular drugs is uniquely bactericidal against both actively dividing and slow-replicating semi-dormant tubercle bacilli residing within acidic intracellular environments (caseous lesions)?

   1. A.Isoniazid
   2. B.Ethambutol
   3. C.Pyrazinamide
   4. D.Streptomycin
   See the answer and solution