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Dynamics of clonal and plasmid backgrounds of Enterobacteriaceae producing acquired AmpC in Portuguese clinical settings over time

2019; Elsevier BV; Volume: 53; Issue: 5 Linguagem: Inglês

10.1016/j.ijantimicag.2019.03.013

1872-7913

Teresa Gonçalves Ribeiro, Ângela Novais, Carla Rodrigues, Renata Medeiros do Nascimento, Francisco Freitas, Elisabete Machado, Luı́sa Peixe,

Antibiotics Pharmacokinetics and Efficacy

The objective of this work was to provide detailed molecular data on clinically acquired AmpC (qAmpC)-producing Enterobacteriaceae from two different periods (2002-2008 and 2010-2013) in order to clarify the contribution of clonal and plasmid genetic platforms for the current epidemiological scenario concerning extended-spectrum beta-lactams resistance.We analysed 1246 Enterobacteriaceae non-susceptible to third-generation cephalosporins from two hospitals and one community laboratory between 2010 and 2013. Bacterial identification, antibiotic susceptibility, identification of qAmpC and plasmid-mediated quinolone resistance genes, clonal (pulsed-field gel electrophoresis (PFGE), Multilocus sequence typing (MLST)) and plasmid (S1-/I-CeuI-PFGE, replicon typing, hybridization) analysis were performed by standard methods. Whole-genome sequencing (WGS) was performed in two ST11-Klebsiella pneumoniae isolates harbouring DHA-1.The occurrence of qAmpC was lower (2.6%) than that observed in a previous survey (7.4%), and varied slightly over time. Isolates produced DHA-1 (53%), CMY-2 (44%) or DHA-6 (3%), but significant epidemiological changes were observed in the two surveys. While DHA-1 persisted in different institutions by selection of a worldwide epidemic IncR plasmid in an ST11 harbouring KL105, CMY-2 rates increased over time linked to IncI1 plasmids (instead of IncK or IncA/C2) in multiple Escherichia coli clones.The higher frequency of DHA-1 qAmpC in these species contrasts with the scenario in most European countries. Furthermore, the different genetic backgrounds associated with either extended-spectrum β-lactamases (ESBLs) or acquired AmpC β-lactamases (qAmpC) in our country might have contributed to their differential expansion.