1. Epidemiology and risk factors for infections due to AmpC β-lactamase-producing Escherichia coli.
- Author
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Pascual, Vanesa, Ortiz, Gabriel, Simó, Maria, Alonso, Noemí, Garcia, Maria Consol, Xercavins, Mariona, Rivera, Alba, Morera, Maria Antonia, Miró, Elisenda, Espejo, Elena, Navarro, Ferran, Gurguí, Mercè, Pérez, Josefa, Rodríguez-Carballeira, Mónica, Garau, Javier, and Calbo, Esther
- Subjects
BETA lactamases ,AMIDASES ,ESCHERICHIA coli ,ESCHERICHIA ,COLIFORMS - Abstract
Objectives To describe the prevalence and risk factors for infection due to AmpC β-lactamase-producing Escherichia coli (AmpC-EC). Methods For the prevalence study, all clinical isolates of E. coli with reduced susceptibility to third-generation cephalosporins were prospectively included from June 2010 to November 2011. For risk factor analysis, a case–control study was conducted. Cases were patients with an infection due to AmpC-EC. Controls were patients infected with cephalosporin-susceptible E. coli, matched 1 : 2. Detection of blaAmpC genes was done with a multiplex AmpC–PCR, and hyperproduction of E. coli chromosomal blaAmpC by quantitative RT–PCR. Alteration of the blaAmpC promoter was studied by PCR and sequencing. Results We identified 243 (1.1%) AmpC-EC strains out of 21 563 clinical isolates. Three cases with strains carrying ESBLs, 18 strains that were considered due to colonization and 8 cases lost to clinical follow-up were excluded. Finally, 214 cases were included in the analysis. Ninety-one cases (42.5%) and 269 (62.8%) controls were strictly community acquired (P < 0.001). Thirty-five (16.3%) cases and 186 controls (43.5%) did not have any identifiable risk factor (P < 0.001). Among cases, 158 (73.8%) were found to harbour an acquired AmpC (73.4% CMY-2). Previous use of fluoroquinolones [OR 2.6 (95% CI 1.12–3.36); P = 0.008] was independently associated with AmpC-EC in the multivariate analysis. Conclusions Prevalence of AmpC in E. coli remains low in our area. Plasmid acquisition (CMY type) represents the main mechanism of AmpC production. A high proportion of community-acquired isolates and patients with no identifiable risk factors were found. Previous use of fluoroquinolones was identified as a risk factor. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
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