Antimicrobial Resistance in NontyphoidalSalmonellafrom Food Sources in Colombia: Evidence for an Unusual Plasmid-Localized Class 1 Integron in Serotypes Typhimurium and Anatum

Abstract

Seventy-two isolates representing 18 serotypes recovered from various food samples collected in Colombia were tested for antimicrobial susceptibilities. The collection was further characterized for extended-spectrum cephalosporin, aminoglycoside, and tetracycline resistance markers. Multidrug resistant (MDR) isolates were further investigated for class 1 integrons and were evaluated for the presence of conjugative plasmids along with a determination of the incompatibility group by polymerase chain reaction (PCR). Antibiogram analysis showed that the incidence rate of ceftiofur resistance was moderately high (15%). A similar level of resistance to neomycin and oxytetracycline (11% and 10%, respectively) was also observed. There was a high prevalence of gene cassettes as part of one or more class 1 integrons (61%), many of which contained determinants that contributed to the resistance profile. Class 1 integrons identified in MDR Salmonella enterica serotypes Typhimurium and Anatum isolates were characterized. Sequencing identified several incomplete open reading frames (ORFs) as part of a gene cassette (bla-( imp-13 ), dfr7, blr1088, and aac8) along with a complete gene cassette (bla-(oxa2)) in each case. A mosaic of gene cassettes was identical in the two Salmonella serotypes. These integrons were located to a conjugative replicon. Plasmid profiling and incompatibility typing identified three plasmids belonging to Inc groups A/C, P, and W. Our study highlights the role of integrons, contributing to a MDR phenotype that is capable of dissemination to other bacteria.

Resistance Plasmid Families in Enterobacteriaceae

“…The scaffolds of these plasmids were similar to those of the IncA/C plasmids carrying bla CMY-2 or bla CMY-4 from S. enterica isolated in the United States and the United Kingdom, but the carbapenemase gene was not present on these Salmonella plasmids and likely represents a novel acquisition for the IncA/C plasmids (23,48). IncA/C-IncP multireplicon plasmids carrying the bla IMP-13 gene were also identified in Salmonella found in food sources in Colombia (79).…”

Evolution of IncA/C bla CMY-2 -Carrying Plasmids by Acquisition of the bla NDM-1 Carbapenemase Gene

“…IncA/ C-IncP multireplicon plasmids carrying the bla IMP-13 gene were also identified in Salmonella isolates from food sources in Colombia (20). Apart from carbapenemase genes, it was also demonstrated previously that IncA/C-type plasmids were at the origin of the worldwide spread of the ESBL gene bla VEB-1 (often associated to the quinolone resistance gene qnrA1) in members of the Enterobacteriaceae (26).…”

Results of the national surveillance of antimicrobial resistance of Enterobacteriaceae and Gram negative bacilli in health care-associated infections in Colombia, 2012-2014

“…En el periodo de vigilancia analizado en el presente estudio, se detectó por primera vez la carbapenemasa IMP en un aislamiento clínico, aunque esta enzima ya había sido reportada en el país en 2006, en un aislamiento de Salmonella enterica proveniente de muestras de alimentos recolectadas en la costa Caribe (22). También, se detectó por primera vez la GES, la cual también se ha reportado en Brasil y Canadá (23,24).…”