Salmonella Heidelberg and Salmonella Minnesota in Brazilian broilers: Genomic characterization of third‐generation cephalosporin and fluoroquinolone‐resistant strains

Abstract

Salmonella serovars Heidelberg and Minnesota encoding antimicrobial resistance to third‐generation cephalosporins and fluoroquinolones are often detected in poultry/poultry meat. We analysed the genomes of 10 Salmonella Heidelberg (SH) and 4 Salmonella Minnesota (SM) from faecal isolates of Brazilian poultry. These featured virulent and multidrug‐resistant characteristics, with AmpC beta‐lactamase (blaCMY‐2) predominance (9/14), for all SM (4/4) and some SH (3/10) located on IncC plasmid replicons. IncC carrying blaCTX‐M‐2 was only detected among SH (3/10). Mutation in the gyrA/parC genes was present in all SH, whereas SM harboured parC mutation plus qnrB19 on ColRNAI plasmids (3/4). In silico resistance overall corroborated with phenotypic results. Core genome phylogenies showed close clustering and high similarities between the Brazilian and poultry meat/food isolates from Europe, and to human isolates from European countries with documented import of Brazilian poultry meat. Conjugation assays with SM successfully transferred blaCMY‐2, and qnrB19 to an Escherichia coli recipient. The findings reinforce the ongoing antimicrobial resistance acquisition of SH and Minnesota and the risks for disseminating resistant strains and/or mobile elements which may increasingly affect importing countries and the need for controlling AMR in major poultry‐exporting countries like Brazil.

Development and characterization of a bacteriophage cocktail with high lytic efficacy against field-isolated Salmonella enterica

“…Recent reports from the EFSA determined the most prevalent serovars in broiler chickens in Europe were Infantis, Enteritidis, Livingstone and Mbandaka ( EFSA and ECDC, 2022 ). However, in Brazilian farms the recent rising of Minnesota and Heidelberg serovars is of high concern for the poultry industry ( Kipper et al, 2021 ; Alikhan et al, 2022 ; Saidenberg et al, 2023 ). Thus, the collection of strains used in this study is likely an updated representation of what is circulating in Brazilian farms.…”

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“…O perfil de resistência antimicrobiana classificou 97,7% destes isolados como multirresistentes. A presença de estirpes bacterianas multirresistentes -MDR na produção animal têm aumentado nos últimos anos, e vêm se tornado uma grande preocupação associada ao consumo de carne de frango Saidenberg et al, 2022). Um estudo recente relacionados a resistência aos antibióticos mostrou que S. Heidelberg e S. Minnesota isoladas de aves no Brasil são portadoras dos genes de resistência blaCMY-2, blaCTX-M-2 e qnrB19 (Saidenberg et al, 2022).…”