Dados do Trabalho

Título

Genomic characterization and genetic context of CMY-2-producing Salmonella enterica serovars Heidelberg and Minnesota isolated from poultry and chicken meat.

Introdução

Salmonella enterica serovars Minnesota and Heidelberg are often found in Brazilian poultry and meat products. As the world's largest poultry meat exporter, Brazil plays a major role in spreading resistant Salmonella. These serovars frequently carry mobile genetic elements that spread resistance genes such as blaCMY-2.  

Objetivo (s)

This study aims to characterize the resistance determinants and genetic context of blaCMY-2-producing S. Heidelberg and Minnesota isolated from poultry and chicken meat. 

Material e Métodos

We included 20 isolates identified as S. Heidelberg (n=16) and S. Minnesota (n=4) from 2012-2018, received by the Bacteriology Center (IAL). DNA extraction was carried out  using the Wizard Genomic DNA Purification Kit. Whole-genome sequencing was performed using Ion Torrent S5 plataform. For plasmid characterization, long-read sequencing was conducted with MiniON. In silico serotyping, resistance genes identification, plasmid grouping (Inc), and plasmid Sequence type (pMLST) were determined using online tools provide by CGE. The genetic context of blaCMY-2 and comparative plasmid analysis were characterized using BioNumerics 8.0 and BRIG software. 

Resultados e Conclusão

In addition to  CMY-2, most isolates showed resistance genes to aminoglycosides (aac(6')-Iaa, aadA1, aph(3’)-Ia), sulfonamides (sul2), fosfomycin (fosA7), fluoroquinolones (qnrB19), and tetracycline (tet(A)). Mutations in the parC gene (T57S) (20/20; 100%) and gyrA gene (S83Y) (16/20; 80%) were identified, conferring resistance to quinolones/fluoroquinolones. In serovar Minnesota, only the parC mutation gene was identified. In serovar Heidelberg,  six Inc groups were identified: IncC (15/16;93,7%), ColpVC (16/16;100%), IncI1 and IncX1 (14/16;87,5%), Col(pHAD28) (10/16;50%) e pEC4115 (2/16;10%). In all  isolates of serovar Minnesota only IncC and Col(pHAD28) (4/4;100%) were identified.In Heidelberg, the plasmid group and ST were IncI1/ST12, while in Minnesota it was IncC/ST2. Both serovars exhibited the same genetic context ISEcp1-blaCMY-2-blc-sugE. The sugE gene confers resistance to disinfectants like quaternary ammonium compounds. In general, these plasmids showed similarity with plasmids from Canada, Georgia, Russia, and Brazil (SC) isolated from poultry, poultry meat, and food. Our results underscore the importance of monitoring antimicrobial resistance genes that can be spread by plasmids identified in strains of both serovars isolated from poultry and poultry meat in Brazil,  the world's largest chicken-exporting country.

Palavras Chave

Salmonella; blaCMY-2; genome characterization; poultry