29. The mode of action of polymyxin is to
A.inhibit protein synthesis
B.inhibit DNA synthesis
C.njury to the plasma membrane
D.inhibit folic acid synthesis
30. Polyene antibiotics are
A.large ring structures
B.β-lactam - thiazolidine ring
C.small ring structures
D.any of these
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 agents is
A.cefotaxime
B.cefoxitin
C.cephalothin
D.cephalexin
33. The penicillin resistant to β-lactamases is
A.carbenicillin
B.closacillin
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
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