Inhibitory effect of clindamycin on production of beta-lactamase in beta-lactam-resistant bacteria.
The inhibitory effect of clindamycin on beta-lactamase biosynthesis was investigated in beta-lactam resistant bacteria with inducible and/or constitutive production of the enzyme(s). Clinical isolates of Enterobacter cloacae (E. cloacae) and Pseudomonas aeruginosa (P. aeruginosa) were examined. Three strains of each, against which sulbactam at 8 micrograms/ml reduced the minimum inhibitory concentration (MIC) of cefoperazone (CPZ) at least 4 fold, were studied in greater detail. Although clindamycin had no appreciable effect on bacteria growth at concentrations up to 50 micrograms/ml, it suppressed inducible beta-lactamase biosynthesis almost completely at a concentration of 20 micrograms/ml. There was also a significant reduction of constitutive enzyme biosynthesis by clindamycin at 50 micrograms/ml. Thus, it was estimated that a high concentration of clindamycin was required to suppress beta-lactamase biosynthesis in beta-lactamase producing bacteria of the constitutive type.
Nishihata
T
T
Upjohn Tsukuba Research Laboratories, Ibaraki, Japan.
Kunieda
S
S
Nakahama
C
C
Soejima
R
R
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002981:Clindamycin / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D016972:Enterobacter cloacae / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology*; D013055:Spectrophotometry, Infrared; D013407:Sulbactam / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D002981:Clindamycin; D001618:beta-Lactamases; D013407:Sulbactam