Objectives: To characterize the genetic determinants responsible for extended-spectrum cephalosporin (ESC) resistance of D-tartrate-positive Salmonella enterica subsp. enterica serovar Paratyphi B (serovar Paratyphi B dT+) strains that have emerged in poultry and humans in Belgium during 2008-10. Methods: The ESC resistance genes among non-redundant serovar Paratyphi B dT+ strains were determined using PCR and sequencing. ESC phenotypes were horizontally transferred by conjugation. Extended-spectrum β-lactamase (ESBL)-or AmpC-carrying plasmids were typed by PCR-based replicon typing, plasmid multilocus sequence typing and restriction fragment length polymorphism. The genetic relationship of ESC-resistant strains was assessed by XbaI PFGE and multilocus sequence typing. Results: Since 2008, the proportion of serovar Paratyphi B dT+strains frombroiler origin has increased significantly to reach 36.5% in 2010. Among 95 non-duplicate serovar Paratyphi B dT+ strains, 35% were resistant to ESCs. At the same time, a few ESC-resistant serovar Paratyphi B dT+ strains from humans were also detected in Belgium. Themost prevalent ESBL gene, blaCTX-M-1, and the AmpC cephalosporinase gene blaCMY-2 were identified on various conjugative IncI1 plasmids of different sequence types and with different additional non-β-lactam phenotypes. Interestingly, the blaCTX-M-2 gene was located on large multireplicon IncHI2/P plasmids. In addition, highly ESCresistant strains contained both the ESBL CTX-M-2 and the AmpC CMY-2 encoded by the IncHI2/P and IncI1 plasmids, respectively. All ESC-resistant serovar Paratyphi B dT+strains belonged to sequence type 28 and showed the common PFGE pattern X8, as well as the chromosomal class 2 integron cassette array dfrA1-sat2-aadA1 previously described in the European poultry-associated serovar Paratyphi B dT+ clonal population. Conclusions: This study showed that the clonal population of multidrug-resistant serovar Paratyphi B dT+, persisting in broilers in Belgium for the last decade, recently acquired various plasmid-borne ESC resistance determinants, constituting a major concern for public health. Further surveillance programmes and research are an absolute necessity to understand their epidemiology and to propose interventions to limit the spread of ESC-and multidrug-resistant Salmonella spp.© The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.
Mendeley helps you to discover research relevant for your work.
CITATION STYLE
Doublet, B., Praud, K., Nguyen-Ho-Bao, T., Argudín, M. A., Bertrand, S., Butaye, P., & Cloeckaert, A. (2014). Extended-spectrum β-lactamase-and ampc β-lactamase-producing D-tartrate-positive Salmonella enterica serovar Paratyphi B from broilers and human patients in Belgium, 2008-10. Journal of Antimicrobial Chemotherapy, 69(5), 1257–1264. https://doi.org/10.1093/jac/dkt504