Population structure of the Salmonella enterica serotype Oranienburg reveals similar virulence, regardless of isolation years and sources.

Salmonella enterica serotype Oranienburg is a multi-host, ubiquitous, and prevalent Non-typhoidal Salmonella (NTS) in subtropical rivers, particularly in sediments; little studied so far possible the adaptation and establishment of this microorganism based on its genetic content. This study was focused on the first five genomes of S. Oranienburg in sediments through whole-genome sequencing (WGS) and 61 river water genomes isolated in previous studies. Results showed an open pangenome with 5,594 gene clusters (GCs), and the division of their categories showed; 3,303 core genes, 741 persistent genes, 1,282 accessory genes, and 268 unique genes. Additionally, it showed three main subclades within the same serotype and showed a conserved genetic content, suggesting the display of different adaptation strategies to its establishment. Nine genes for antimicrobial resistance were detected: aac (6') - Iy, H-NS, golS, marA, mdsABC, mdtK, and sdiA, and a mutation in the parC gene p. T57S generating a resistance. In addition, virulence genes and pathogenicity islands (SPI's) were analyzed, finding 92 genes and an identity above 80 % in the SPI's 1 to 5, and the centisomes 54 and 63. The environmental strains of S. Oranienburg do not represent a concern as multidrug resistance (MDR) bacterium; however, virulence genes remain a potential health risk. This study contributes to understanding its adaptation to aquatic environments in Mexico.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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