title: [Detection of beta-lactamases resistant to inhibitors (IRT) by the disk diffusion method].
abstract: 85 E. coli strains producing various beta-lactamase were studied: TEM low level: n = 11, TEM high level: n = 4, oxacillinase (OXA): n = 5, céphalosporinase (CASE) +/- TEM: n = 5, inhibitor resistant TEM (IRT) n = 50, IRT+TEM: n = 3, IRT+
  
  
  METHODS
  n = 7. Their susceptibility to amoxicillin (AMX), amoxicillin+clavulanate (AMC), ticarcillin (TIC), ticarcillin+clavulanate (TCC), piperacillin (PIP), piperacillin+tazobactam (TAZ), mecillinam (MEC), cephalotin (CF), cefoxitin (FOX) et ceftazidime (CAZ) were evaluated by a disk diffusion method, in order to determine the resistance pattern which allows a reliable detection of IRT-producing strains. The phenotype AMX R, TIC R, AMCI/R, TCCI/R et CFS was observed in 46 out of 53 IRT +/- TEM strains, 4/5 of OXA strains and 1/11 of TEM low level strains. A better sensitivity could be obtained by a modification of breakpoints for AMC, TCC and CF, however OXA-producing strains remain indistinguishable from IRT-strains.
authors.affiliation: Service de Bactériologie, Faculté de Médecine, Clermont-Ferrand, France.
authors.forename: J P
authors.initials: JP
authors.lastname: Romaszko
authors.forename: L
authors.initials: L
authors.lastname: Bret
authors.forename: C
authors.initials: C
authors.lastname: Henquell
authors.forename: D
authors.initials: D
authors.lastname: Sirot
authors.forename: C
authors.initials: C
authors.lastname: Chanal
authors.forename: J
authors.initials: J
authors.lastname: Sirot
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases
vernacular_title: Détection des beta-lactamases résistantes aux inhibiteurs (IRT) par la méthode de diffusion.