31. Which of the following may cause resistance to penicillin?
A. Impermeability of cell envelope
B. Production of β-lactamases by bacteria
C. Alteration or lack of penicillin-binding proteins
D. All of the above
32. The third-generation cephalosporin agent is
A. cefotaxime
B. cefoxitin
C. cephalothin
D. cephalexin
33. The penicillin-resistant to β-lactamases is
A. carbenicillin
B. cloxacillin
C. penicillin-G
D. ampicillin
34. The antibiotics not clinically useful for Pseudomonas aeruginosa infection is
A. aminoglycosides
B. ceftazidime
C. piperacillin
D. trimethoprim-sulphamethoxazole
35. Which of the following drugs may show plasmid-mediated resistance?
A. Nalidixic acid
B. Ampicillin
C. Rifampicin
D. Methicillin