Explore the vast range of titles available.

The rise of antimicrobial resistance (AMR) in Salmonella enterica poses a significant public health threat, particularly through the dissemination of extended-spectrum β-lactamase (ESBL) genes such as bla CTX-M-65 . This study investigated the prevalence, resistance profiles, and genomic characteristics of S . enterica isolates from retail poultry products in North Carolina, collected between 2020 and 2024. Among 132 isolates representing 25 serovars, 14 were identified as multidrug-resistant (MDR) strains harboring bla CTX-M-65 . Whole-genome sequencing revealed that these isolates belonged to three serovars— S . Infantis (n = 11), S . I -:r:1,5 (n = 2), and S . Senftenberg (n = 1)—with associated sequence types ST32 and ST14. Genomic analyses identified additional resistance determinants, including quinolone resistance-determining region (QRDR) mutations, and a range of mobile genetic elements, such as IncFIB(pN55391) plasmids. The genetic environment of bla CTX-M-65 was conserved, with IS 1380 - bla CTX-M-65 -IS 5 structures, highlighting its mobility potential. Phylogenetic analysis showed that isolates clustered by serovar, with strong associations to international lineages. These findings emphasize the ongoing clonal dissemination of bla CTX-M-65 and MDR Salmonella in the food supply chain, necessitating enhanced surveillance and mitigation strategies to curb the spread of resistance genes in food production environments.

International lineages, such as Salmonella Typhimurium sequence type (ST) 19, are most often associated with foodborne diseases and deaths in humans. In this study, we compared the whole-genome sequences of five S. Typhimurium strains belonging to ST19 recovered from clinical human stool samples in North Carolina, United States. Overall, S. Typhimurium strains displayed multidrug-resistant profile, being resistance to critically and highly important antimicrobials including ampicillin, ticarcillin/clavulanic acid, streptomycin and sulfisoxazole, chloramphenicol, tetracycline, respectively. Interestingly, all S. Typhimurium strains carried class 1 integron (intl1) and we were able to describe two genomic regions surrounding blaCARB-2 gene, size 4,062 bp and 4,422 bp for S. Typhimurium strains (HS5344, HS5437, and HS5478) and (HS5302 and HS5368), respectively. Genomic analysis for antimicrobial resistome confirmed the presence of clinically important genes, including blaCARB-2, aac(6')-Iaa, aadA2b, sul1, tetG, floR, and biocide resistance genes (qacEΔ1). S. Typhimurium strains harbored IncFIB plasmid containing spvRABCD operon, as well as rck and pef virulence genes, which constitute an important apparatus for spreading the virulence plasmid. In addition, we identified several virulence genes, chromosomally located, while the phylogenetic analysis revealed clonal relatedness among these strains with S. enterica isolated from human and non-human sources obtained in European and Asian countries. Our results provide new insights into this unusual class 1 integron in virulent S. Typhimurium strains that harbors a pool of genes acting as potential hotspots for horizontal gene transfer providing readily adaptation to new surrounds, as well as being crucially required for virulence in vivo. Therefore, continuous genomic surveillance is an important tool for safeguarding human health.

Shiga toxin–producing Escherichia coli (STEC) is an important pathogen with public health implications, including its potential association with vegetables. In this study, we investigated the presence of STEC in vegetables obtained from organic producers located in São Paulo city, Brazil. As part of a routine surveillance study conducted over (years of isolation), a total of 200 samples of organic vegetables were screened using biochemical and PCR methods. Among the vegetable samples tested, 30 (15%) were positive for non-Shiga toxin–producing E. coli . While no STEC was detected in the organic vegetables in this study, the presence of non-STEC in vegetables raises concerns about the lack of proper hygiene practices during vegetable handling. This contamination represents a public health risk, particularly considering that these isolates can still be pathogenic, and vegetables are often consumed raw. To address this important issue, continuous monitoring of these farms is recommended to ensure the quality and safety of organic vegetables produced for both domestic consumption and exportation.

In this study, a total of 248 ground beef samples were analyzed for the presence of Shiga toxin-producing Escherichia coli (STEC). Out of these samples, only one (0.4%) tested positive for STEC. Further analysis using PCR confirmed the presence of all tested genes associated with STEC, including stx1 , stx2 , eae , ehx , uid , rfbO157 , and fliCH7 in this isolate. Interestingly, no STEC strains were detected in the remaining 100 beef cut samples or the 100 chicken cut samples, indicating the absence of detectable STEC contamination in those specific samples. The isolated strain exhibited significant cytotoxic activity in Vero cells, indicating its ability to produce cytotoxic Shiga toxins. To further investigate the strain, whole-genome sequencing (WGS) analyses were performed. The resistome analysis revealed the absence of acquired antimicrobial resistance genes, indicating a pan-susceptible phenotype. However, this strain presented chromosomal mutations in gyrA , gyrB , parC , parE , pmrA , pmrB , and folP . Plasmid analysis identified the presence of two plasmids, namely IncFIB(AP001918) and IncFII. The multi-locus sequence typing (MLST) identified the strain as belonging to sequence type (ST) 11, which is associated with E. coli O157:H7 strains. The virulome analysis confirmed the presence of several canonical virulence markers, including stx1 , stx2 , eae-g01-gamma , ehxA , stx1a-O157 , and stx2a-O157 . Overall, this study identified for the first time a rare occurrence of STEC contamination in ground beef, with the isolated strain belonging to the highly virulent O157:H7 serotype. These findings contribute to our understanding of STEC prevalence and characteristics in food samples, highlighting the importance of effective food safety measures to prevent potential health risks associated with STEC contamination.