title: Prevalence and molecular epidemiology of acquired AmpC β-lactamases and carbapenemases in Enterobacteriaceae isolates from 35 hospitals in Spain.
abstract: The purpose of this investigation was to determine the prevalence of plasmid-mediated AmpC (pAmpC) and carbapenemases in Enterobacteriaceae collected from 35 hospitals in Spain and to establish their epidemiological relationships. We conducted a prospective multi-centre study on pAmpC- or carbapenemase-producing Enterobacteriaceae isolates from clinical samples collected from February to July 2009. The strains suspected to carry pAmpC were resistant or showed intermediate susceptibility to co-amoxiclav and second- or third-generation cephalosporins. Strains suspected to carry a carbapenemase were selected because they showed a minimum inhibitory concentration (MIC) to imipenem >1 mg/L. Polymerase chain reaction (PCR) and a sequencing strategy were used to characterise the enzymes. The clonal relationships between isolates was analysed by pulsed field gel electrophoresis (PFGE). Among 100,132 Enterobacteriaceae isolates collected, 1,654 were compatible with the production of pAmpC or carbapenemases. We found a prevalence of 0.64 % of pAmpC (n = 635) and 0.04 % of carbapenemases (n = 43). The most prevalent pAmpC enzymes were CMY-type (78.3 %), DHA-type (19.5 %), ACC-type (1.6 %) and FOX-type (0.6 %). The CMY-type was the most frequent in Escherichia coli and Proteus mirabilis species, whereas the DHA-type was mainly found in Klebsiella spp. The enzymes involved in carbapenem resistance were VIM-1, IMP-22 and the new IMP-28. Nine new bla genes were described: bla (CMY-54), bla (CMY-55), bla (CMY-56), bla (CMY-57), bla (CMY-96), bla (DHA-6), bla (DHA-7), bla (FOX-8) and bla (IMP-28). The prevalence of pAmpC or carbapenemases found is not negligible. The CMY-types were the predominant pAmpC, whereas the VIM or IMP enzymes were the predominant carbapenemases. Furthermore, we observed a great genetic diversity among pAmpC-producing strains and a close clonal relationship between carbapenemase-producing strains.
authors.affiliation: Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica Sant Pau, Sant Quintí 89, 08041 Barcelona, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Miró
authors.forename: J
authors.initials: J
authors.lastname: Agüero
authors.forename: M N
authors.initials: MN
authors.lastname: Larrosa
authors.forename: A
authors.initials: A
authors.lastname: Fernández
authors.forename: M C
authors.initials: MC
authors.lastname: Conejo
authors.forename: G
authors.initials: G
authors.lastname: Bou
authors.forename: J J
authors.initials: JJ
authors.lastname: González-López
authors.forename: N
authors.initials: N
authors.lastname: Lara
authors.forename: L
authors.initials: L
authors.lastname: Martínez-Martínez
authors.forename: A
authors.initials: A
authors.lastname: Oliver
authors.forename: B
authors.initials: B
authors.lastname: Aracil
authors.forename: J
authors.initials: J
authors.lastname: Oteo
authors.forename: A
authors.initials: A
authors.lastname: Pascual
authors.forename: J
authors.initials: J
authors.lastname: Rodríguez-Baño
authors.forename: L
authors.initials: L
authors.lastname: Zamorano
authors.forename: F
authors.initials: F
authors.lastname: Navarro
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology*; D005838:Genotype; D006761:Hospitals; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010957:Plasmids / Q000032:analysis; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D013030:Spain / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases