Antimicrobial resistance and genomic characterization of Salmonella enterica serovar Senftenberg isolates in production animals from the United States

Abstract

In the USA, Salmonella enterica subspecies enterica serovar Senftenberg is among the top five serovars isolated from food and the top 11 serovars isolated from clinically ill animals. Human infections are associated with exposure to farm environments or contaminated food. The objective of this study was to characterize S. Senftenberg isolates from production animals by analyzing phenotypic antimicrobial resistance profiles, genomic features and phylogeny.Salmonella Senftenberg isolates (n = 94) from 20 US states were selected from NVSL submissions (2014–2017), tested against 14 antimicrobial drugs, and resistance phenotypes determined. Resistance genotypes were determined using whole genome sequencing analysis with AMRFinder and the NCBI and ResFinder databases with ABRicate. Plasmids were detected using PlasmidFinder. Integrons were detected using IntFinder and manual alignment with reference genes. Multilocus-sequence-typing (MLST) was determined using ABRicate with PubMLST database, and phylogeny was determined using vSNP.Among 94 isolates, 60.6% were resistant to at least one antimicrobial and 39.4% showed multidrug resistance. The most prevalent resistance findings were for streptomycin (44.7%), tetracycline (42.6%), ampicillin (36.2%) and sulfisoxazole (32.9%). The most commonly found antimicrobial resistance genes were aac(6′)-Iaa (100%), aph(3″)-Ib and aph(6)-Id (29.8%) for aminoglycosides, followed by blaTEM-1 (26.6%) for penicillins, sul1 (25.5%) and sul2 (23.4%) for sulfonamides and tetA (23.4%) for tetracyclines. Quinolone-resistant isolates presented mutations in gyrA and/or parC genes. Class 1 integrons were found in 37 isolates. Thirty-six plasmid types were identified among 77.7% of the isolates. Phylogenetic analysis identified two distinct lineages of S. Senftenberg that correlated with the MLST results. Isolates were classified into two distinct sequence types (ST): ST14 (97.9%) and ST 185 (2.1%). The diversity of this serotype suggests multiple introductions into animal populations from outside sources.This study provided antimicrobial susceptibility and genomic characteristics of S. Senftenberg clinical isolates from production animals in the USA during 2014 to 2017. This study will serve as a base for future studies focused on the phenotypic and molecular antimicrobial characterization of S. Senftenberg isolates in animals. Monitoring of antimicrobial resistance to detect emergence of multidrug-resistant strains is critical.

Characterization of Salmonella spp. in a tertiary hospital during 2019-2021 in Nanjing, China: Focusing on the clonal dissemination of Salmonella Enteritidis ST11

“…The high frequency of resistance to ampicillin and ampicillin/sulbactam in our study was similar to the previous reports from China [27,29], Italy [28], and Argentina [30], suggesting that ampicillin and ampicillin/sulbactam should be carefully prescribed for clinical treatment of infections caused by such strains. In addition, resistance to sulfamethoxazole/trimethoprim in our study was lower than those in previous domestic and foreign studies [29][30][31][32], however, relatively higher than those of other studies [33,34]. The reason may lie on the regional or strain difference.…”

The spread of pESI-mediated extended-spectrum cephalosporin resistance inSalmonellaserovars - Infantis, Senftenberg, and Alachua isolated from food animal sources in the United States

“…In addition to the antimicrobial resistance genes, all pESI and pESI-like plasmids carried virulence genes encoding for fimbriae clusters, yersiniabactin siderophore, toxin/antitoxin systems, and resistance genes for mercury and disinfectant (15). In vitro and in vivo studies showed that the Infantis strains with the pESI-like plasmid were superior in biofilm formation, adhesion, and invasion into avian and mammalian host cells (4,16). The carriage of this plasmid by Infantis likely leads to the rapid spread of the recipient clones.…”

Exposing Salmonella Senftenberg and Escherichia coli Strains Isolated from Poultry Farms to Formaldehyde and Lingonberry Extract at Low Concentrations

“…Salmonella infections are most often caused by the consumption of contaminated dairy products, meat, eggs, as well as fruit and vegetables, which may be the result of contamination of the soil or water used in the cultivation [5]. In the USA, Salmonella enterica serovar Senftenberg is among the top five serovars isolated from food [6], and there is little information about its susceptibility to chemical disinfectants. Colibacillosis, the etiological factor of which is pathogenic Escherichia coli strains, is one of the main causes of mortality and morbidity in poultry.…”