International Journal of Medical Microbiology 303 (2013) 553–557 Contents lists available at ScienceDirect International Journal of Medical Microbiology jo ur nal homepage: www.elsevier.co m/locate/ijmm Short communication Molecular epidemiology, resistance profiles and clinical features in clinical plasmid-mediated AmpC-producing Enterobacteriaceae M a Jose Gude a , Cristina Seral a,b,* , Yolanda Sáenz c , Rocío Cebollada a , María González-Domínguez a , Carmen Torres c,d , F. Javier Castillo a,b a Servicio de Microbiología. Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain b Departamento de Microbiología. Universidad de Zaragoza, Zaragoza, Spain c Área de Microbiología Molecular. Centro de Investigación Biomédica de La Rioja (CIBIR), Logro˜ no, Spain d Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logro˜ no, Spain a r t i c l e i n f o Article history: Received 13 March 2013 Received in revised form 17 July 2013 Accepted 20 July 2013 Keywords: Plasmid-mediated AmpC CMY-2 PFGE Clinical features Prevalence Molecular epidemiology a b s t r a c t During the 30 months of surveillance period, 85 pAmpC-producing isolates were detected (prevalence 0.56% overall): bla CMY-2 gene in 70 E. coli, 2 K. pneumoniae and 6 P. mirabilis isolates; and the bla DHA-1 gene in 4 E. coli and 3 K. pneumoniae. In 8.23% of them, other -lactamases (predominantly OXA-1) were identified. All pAmpC-producing isolates were susceptible to carbapenems, whereas high resistance to nalidixic acid, ciprofloxacin and trimethoprim-sulfamethoxazole was observed among pAmpC-producing isolates (80%, 60%, and 44.7%, respectively). In hospital patients, predisposing factors such as prior antibiotic use, previous hospitalization, presence of an indwelling device, invasive urinary tract procedures and mechanical ventilation were observed. In the community setting, urinary tract infection was the most common type of infection related to pAmpC-producing isolates. A wide heterogeneity of clones was found among our E. coli isolates by PFGE, suggesting that this mechanism of resistance is not due to the dissemination of a clonal strain. Surveillance of these resistance mechanisms in the community is thus needed. Awareness of pAmpC dynamic is required to prevent introduction into hospitals and to control the spread of this emerging resistance within the community. © 2013 Elsevier GmbH. All rights reserved. Introduction Plasmid-mediated AmpC -lactamases (pAmpC) are antimi- crobial resistance mechanisms clinically significant because preferentially hydrolyze all -lactams except fourth-generation cephalosporins and carbapenems. They have been mainly detected in Escherichia coli, Klebsiella spp., Salmonella spp., and Proteus mirabilis (Philippon et al., 2002; Jacoby, 2009; Seral et al., 2012). pAmpC-harbouring isolates are usually multi-resistant because these ampC genes could be located onto large plasmids that con- tain additional antimicrobial resistance genes (Philippon et al., 2002; Jacoby, 2009). Their prevalence could be underestimated because reference guidelines do not still indicate either phenotypic screening or confirmatory tests to detect pAmpC. And, in addition, there are only few data concerning to the predisposing factors, clinical features and patient details of infections caused by pAmpC * Corresponding author at: Departamento de Microbiología, Facultad de Medicina, Universidad de Zaragoza, San Juan Bosco, 15. 50009 Zaragoza. Spain. Tel.: +34 976 556 400x4319. E-mail address: cseral@unizar.es (C. Seral). producing clinical isolates (Sidjabat et al., 2009; Rand et al., 2011; Park et al., 2012; Rodríguez-Ba ˜ no et al., 2012). The purpose of the present study was to correlate the epidemi- ological features with the molecular epidemiology and resistance profile of pAmpC in E. coli, K. pneumoniae and P. mirabilis clinical isolates that are circulating in our environment. Methods Setting The study was performed in the University Teaching Hospital “Lozano Blesa” (Zaragoza, Spain), with 803 beds attending a pop- ulation of 286,774 inhabitants with 29,506 annual admissions. It includes an outpatient care facility with 2,315,197 annual visits, and an emergency department with 127,694 annual visits. Bacterial isolates and patient information From June 2008 to December 2010, 85 pAmpC-producing iso- lates, included 74 E. coli, five K. pneumoniae and six P. mirabilis, were previously detected in our hospital by four phenotypic meth- ods (Three-dimensional test, AmpC test, Cloxacillin synergy test, 1438-4221/$ – see front matter © 2013 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.ijmm.2013.07.007