title: Characterization of Inhibitor-Resistant TEM β-Lactamases and Mechanisms of Fluoroquinolone Resistance in Escherichia coli Isolates.
abstract: The aim of present work was to characterize the inhibitor-resistant TEM (IRT) β-lactamases produced by Escherichia coli in Hospital Clínico San Carlos (Madrid, Spain). Mechanisms of fluoroquinolone resistance among IRT-producing strains were also studied. Isolates with susceptibility to cephalosporins and amoxicillin-clavulanate (AMC) resistance were collected in our hospital (November 2011-July 2012) from both outpatients and hospitalized patients. Among 70 AMC-resistant E. coli strains, 28 (40%) produced IRT enzymes. Most of them were uropathogens (82.1%) and recovered from outpatients (75%). Seven different IRT enzymes were identified with TEM-30 (IRT-2) being the most prevalent, followed by TEM-40 (IRT-11). A high rate of ciprofloxacin resistance was found among IRT-producing strains (50%). Most of the ciprofloxacin-resistant isolates showed ciprofloxacin minimum inhibitory concentration >32 mg/L and contained two mutations in both gyrA and parC genes. Four IRT enzyme producers harbored the qnr gene. ST131 clone was mainly responsible for both IRT enzyme production and ciprofloxacin resistance. In conclusion, data from this study show that the frequency of IRT producers was 40% and a high rate of ciprofloxacin resistance was found among IRT-producing isolates. Current and future actions should be taken into account to avoid or reduce the development of AMC and fluoroquinolone resistance in E. coli.
authors.affiliation: Microbiology Department, Hospital Clínico San Carlos , Madrid, Spain .
authors.forename: Esther
authors.initials: E
authors.lastname: Ríos
authors.affiliation: Microbiology Department, Hospital Clínico San Carlos , Madrid, Spain .
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: López
authors.affiliation: Microbiology Department, Hospital Clínico San Carlos , Madrid, Spain .
authors.forename: Iciar
authors.initials: I
authors.lastname: Rodríguez-Avial
authors.affiliation: Microbiology Department, Hospital Clínico San Carlos , Madrid, Spain .
authors.forename: Irene
authors.initials: I
authors.lastname: Pena
authors.affiliation: Microbiology Department, Hospital Clínico San Carlos , Madrid, Spain .
authors.forename: Juan Jose
authors.initials: JJ
authors.lastname: Picazo
mesh_terms: D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics / Q000378:metabolism; D027101:DNA Topoisomerase IV / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology; D024841:Fluoroquinolones / Q000494:pharmacology*; D015870:Gene Expression; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D009154:Mutation; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D019980:Amoxicillin-Potassium Clavulanate Combination; D001618:beta-Lactamases; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase