title: Problems in interpretation of piperacillin susceptibility of TEM-1 producing Escherichia coli in the disk diffusion test.
abstract: The susceptibility of 455 Escherichia coli blood culture isolate to piperacillin was tested with the disk diffusion test. The presence of different beta-lactamase genes in these strains was also studied using DNA hybridization. Of the TEM beta-lactamase producing isolates, 64% (61/95) were interpreted as intermediately susceptible to piperacillin. Because piperacillin is hydrolyzed by TEM-type beta-lactamases, we suggest that the intermediate susceptibility category should be reduced or omitted in testing piperacillin susceptibility of Escherichia coli isolates.
authors.affiliation: Department of Medical Microbiology, Turku University, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Arstila
authors.forename: S
authors.initials: S
authors.lastname: Huovinen
authors.forename: P
authors.initials: P
authors.lastname: Huovinen
mesh_terms: D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D009693:Nucleic Acid Hybridization; D010878:Piperacillin / Q000494:pharmacology*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D001618:beta-Lactamases; C034413:beta-lactamase TEM-1; D010878:Piperacillin