Emergence of transferable AmpC beta-lactamase CMY-2 in animal Salmonella in South America.

DOMÍNGUEZ JOHANA; CEJAS DANIELA; RINCÓN GIOVANNA; GUTKIND GABRIEL; DI CONZA JOSÉ; MERCADO ELSA

Washington

Conferencia; 54th ICAAC - Annual Interscience Conference on Antimicrobial Agents and Chemotherapy; 2014

American Society of Microbiology

The increase in transferable AmpC-mediated resistance in zoonotic Salmonellae constitutes a serious public health concern that has been reported from a number of developing and developed countries. These enzymes confer resistance to a wide range of beta-lactams, including third- and fourth-generation cephalosporins. The aim of this study was to report the presence of plasmid-mediated beta-lactamase CMY-2 in Salmonella isolated from an animal in Argentina. Methods Salmonella Typhimurium 2010-16 was isolated in 2010 from a racefoal with diarrhea. Preliminary characterization of CMY-2 was performed after determining the phenotype against beta-lactams and the presence of bla genes by PCR. The genetic context of the blaCMY-2 gene was identified by PCR mapping and further sequencing. Plasmid analysis included determination of transferability and characterization of the incompatibility group by the PCR-based replicon typing (PBRT) applied to transformants or transconjugants. Results The isolate was resistant to ampicillin, ceftriaxone, ceftiofur, and cefoxitin and was proven to be AmpC positive by multiplex PCR. Sequence analysis revealed the presence of blaCMY2. Resistance transfer experiments showed that transconjugants and transformants coexpressed resistance phenotypes similar to the donor isolates. Plasmid size was estimated by PFGE analysis of S1 nuclease digested DNA. According to the PBRT method the plasmid was assigned to the IncI1 group. The blaCMY-2 gene was identified within a transposon-like ISEcp1 truncated element (ΔISEcp1-blaCMY-2-blc-sugE) associated mostly with different plasmids of the incompatibility groups I1. The strain was not found multidrug resistant. Discussion In Argentina, S. enterica serovar Typhimurium ranks among the most prevalent causes of human and animal salmonellosis. Recently, a S. Heidelberg isolate containing a 97 kb plasmid belonging to the Inc N group harboring blaCMY-2 was recovered from an input patient. To the best of our knowledge, this is the first report describing Salmonella from animals capable of producing transferable AmpC beta-lactamase in our country, an even in South America.