A piperacillin-tazobactam resistant Escherichia coli strain isolated from a faecal sample of a healthy volunteer.
As part of a surveillance programme of the prevalence of antibiotic resistance, the faecal bacteria of healthy people (n = 1348) were examined, and the antibiotic resistance of the Escherichia coli strains determined. One strain out of 142 amoxycillin-resistant isolates, E. coli strain 1662, was also resistant to piperacillin-tazobactam but susceptible to amoxycillin-clavulanic acid. The piperacillin-tazobactam resistance determinant was transferable to standard E. coli strains by conjugation. However, the strain produced a beta-lactamase with several characteristics very similar to those of the TEM-1 beta-lactamase, i.e. pI of 5.4, an M(r) value of 22,000 and a comparable substrate profile. The enzyme was as efficiently inhibited by clavulanic acid and tazobactam as the TEM-1 and TEM-2 beta-lactamases but more than the amoxycillin-clavulanic acid-resistant TRC-1 enzyme. The transferable resistance to piperacillin-tazobactam appears to be mediated by a novel resistance mechanism that has previously not been described.
London
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N
University of Limburg, Department of Medical Microbiology, Maastricht, The Netherlands.
Thomson
C J
CJ
Amyes
S G
SG
Stobberingh
E
E
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D005243:Feces / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D010403:Penicillin Resistance; D010878:Piperacillin / Q000494:pharmacology*; D010957:Plasmids / Q000032:analysis; D011159:Population Surveillance; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000096:biosynthesis / Q000737:chemistry
D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D004791:Enzyme Inhibitors; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D010397:Penicillanic Acid; D001618:beta-Lactamases; D000078142:Tazobactam; D010878:Piperacillin