Free Antimicrobial Agents MCQs with Answers

• A. 1% to 10%
• B. 10% to 20%
• C. 20% to 30
• D. 30% to 40%

Explanation: Reported penicillin allergy varies widely among populations, commonly around 1% to 10%.

• A. Inhibiting the binding of aminoacyl tRNA to the ribosomal complex
• B. Inhibiting peptidyl transferase
• C. Inactivating elongation factors
• D. Causing misreading of mRNA

Explanation: Tetracyclines bind the bacterial 30S ribosomal subunit and block attachment of aminoacyl-tRNA to the acceptor site.

• A. Piperacillin
• B. Mezlocillin
• C. Azlocillin
• D. Flucloxacillin

Explanation: Piperacillin, mezlocillin and azlocillin are ureidopenicillins with extended Gram-negative activity.

• A. A long acting macrolide
• B. Short action quinolone
• C. Short acting macrolide
• D. Long acting polypeptide

Explanation: Roxithromycin is a semisynthetic, long-acting macrolide related to erythromycin.

• A. Active against pseudomonas aeruginose
• B. Inhibits Beta-lactamase
• C. It is a ureido penicillin
• D. Given parenterally

Explanation: Piperacillin is a ureidopenicillin active against organisms such as Pseudomonas and is administered parenterally.

• A. Cephadroxil
• B. Cefepime
• C. Cefotaxime
• D. Cefoperazone

Explanation: Cephadroxil is an oral first-generation cephalosporin. Cefotaxime and cefoperazone are third generation, while cefepime is fourth…

• A. Sulphonamide
• B. Carbamide
• C. Cephalosporins
• D. Ofloxacin

Explanation: Cephalosporins contain the beta-lactam ring and inhibit bacterial cell-wall synthesis.

• A. Inhibition of bacterial protein synthesis by binding to subunit of bacterial ribosomes
• B. Inhibition of cell wall peptidoglycan synthesis by competitive inhibition of transpetidases
• C. Reduced drug causes strand breaks in DNA
• D. Inhibition of DNA synthesis by inhibiting DNA-Dependent RNA polymerase

Explanation: Beta-lactams bind penicillin-binding proteins and competitively inhibit transpeptidases, preventing cross-linking of peptidoglycan in the…

• A. Fungal
• B. Viral
• C. Bacterial
• D. Rickettesial

Explanation: Amphotericin B is a polyene antifungal that binds ergosterol in fungal cell membranes and forms pores.

• A. Rifampicin
• B. Vancomycin
• C. Chloramphenicol
• D. Tetracycline

Explanation: Rapid intravenous infusion of vancomycin can cause histamine release, producing flushing and erythema of the face and upper body known as…

• A. Enfuvirtide
• B. Lamivudine
• C. Efavirenz
• D. Ritonavir

Explanation: Lamivudine inhibits reverse transcriptase in HIV and also suppresses hepatitis B virus polymerase, so it has activity against both…

• A. Intravenous Penicillin G
• B. Antihistamines
• C. Tetracyclines
• D. Steroids

Explanation: The Jarisch-Herxheimer reaction is an acute inflammatory response after treatment of spirochetal infection, often causing fever, chills…

• A. is a broad spectrum antiprotozoal drug
• B. Active against bacteroides and clostridium
• C. An effective alternative for infection caused by aerobic gram positive cocci
• D. May cause peripheral neuropathy on prolonged use

Explanation: Metronidazole is active against anaerobes such as Bacteroides and Clostridium and against several protozoa, but it does not effectively…

• A. Red
• B. Green
• C. Yellow
• D. Brown

Explanation: Tetracycline incorporated into developing teeth produces yellow staining and can show yellow fluorescence under ultraviolet light.

• A. Penicillin is inactivated by erythromycin
• B. Erythromycin exerts its effects extracellularly
• C. Erythromycin enhances the B-lactamases activity
• D. Penicillin is only effective against growing cells

Explanation: Penicillins kill actively growing bacteria, whereas erythromycin is bacteriostatic and inhibits their growth, so the two effects can be…

• A. Enfuvirtide
• B. Nelfinavir
• C. Efavirenz
• D. Etanercept:

Explanation: Enfuvirtide is a fusion inhibitor that binds HIV gp41 and prevents fusion of the viral envelope with the host-cell membrane.

• A. Metronidazole
• B. Diloxanide furoate
• C. Quinidochlor
• D. Furazolidone

Explanation: Asymptomatic intestinal amoebic cyst carriage requires a luminal amoebicide, and diloxanide furoate is a standard effective choice.

• A. Cefeperazone
• B. Cefuroxime
• C. Cefoxitin
• D. Cefadroxil

Explanation: Cefoperazone is a third-generation cephalosporin; the option spells it "Cefeperazone." Cefuroxime is second generation, while cefoxitin…

• A. Thiamine
• B. Pyridoxine
• C. Niacin
• D. Riboflavin

Explanation: Isoniazid depletes pyridoxine, or vitamin B6, producing peripheral neuropathy and sometimes seizures.

• A. Bacterial meningitis
• B. Rickettsial infection
• C. Syphilis
• D. Anthrax

Explanation: Penicillin G is used for syphilis, susceptible meningitis, and anthrax, but it has no useful activity against rickettsiae.