Positive from Food in Brazil: Detection and Characterization.

The gene has been identified in bacterial isolates obtained from humans, animals, environment, and food, including spp., which is one of the major foodborne pathogens worldwide. The aim of this study was to evaluate the presence of gene in spp. from food produced in Brazil and to characterize the isolates harboring this gene. A total of 490 spp. isolates from the Brazilian National Program for the Control of Foodborne Pathogens were screened for the presence of gene by polymerase chain reaction (PCR). Whole genome sequencing (WGS) was performed in positive isolates to characterize the sequence type (ST), plasmid families and resistance genes. Antimicrobial susceptibility tests were performed by broth microdilution. Selected isolates were submitted to conjugation experiments using the J53 as a receptor. We detected eight isolates harboring the gene; seven belonged to serovar Typhimurium and its monophasic variant 4,[5],12:i:-, and one belonged to serovar Saintpaul. Seven of the positive isolates displayed a high rate of resistance to other antibiotics in addition to colistin. Analysis of the WGS indicated that the ST 19 was the most common ST among the positive isolates. The gene was located in an IncX4 plasmid of ∼33 kb, with no additional resistance genes and with high identity with a plasmid obtained from a clinical isolate of positive in Brazil. All plasmids harboring the gene were able to conjugate. Our results suggest the spread of a single plasmid type in Brazil harboring the among spp. The horizontal transfer of this mobile element has been contributing to the spread of the colistin resistance in the country.