Activity of amoxycillin/clavulanate against beta-lactamase-producing Escherichia coli and Klebsiella spp.
We studied the susceptibility to the amoxycillin/clavulanate combination (2:1), and the characteristics of the beta-lactamases, of 1410 amoxycillin-resistant strains of Enterobacteriaceae (785 of Escherichia coli and 625 of Klebsiella spp.). Of the E. coli strains, 97.07% were susceptible to the combination and 98.85% produced plasmid-mediated beta-lactamases. Of the Klebsiella spp. strains, 87.84% were susceptible to the combination and 75.36% produced plasmid-mediated beta-lactamases. In both cases, the differences in MIC values, according to the characteristics of the beta-lactamases of the strains, were statistically significant. Of the 99 strains of E. coli and Klebsiella spp. that were not inhibited by amoxycillin 16 mg/l with clavulanate 8 mg/l, 19 hyperproduced chromosomal beta-lactamase; five produced a plasmid-type beta-lactamase as well. Fifty-seven strains produced two plasmid-type beta-lactamases.
Roy
C
C
Instituto Municipal de Investigación Médica, Barcelona, Spain.
Segura
C
C
Torrellas
A
A
Reig
R
R
Teruel
D
D
Hermida
M
M
D000658:Amoxicillin / Q000494:pharmacology*; D002969:Clavulanic Acids / Q000494:pharmacology*; D004359:Drug Therapy, Combination / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D007709:Klebsiella / Q000187:drug effects* / Q000201:enzymology; D007710:Klebsiella Infections / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D001618:beta-Lactamases / Q000096:biosynthesis*
D002969:Clavulanic Acids; D000658:Amoxicillin; D001618:beta-Lactamases