Shigellosis is a serious public health problem worldwide caused by Shigella spp. The aims of this study were to molecularly and phenotypically characterize 50 S. flexneri strains isolated from human feces between 1983 and 2017 in different States of Brazil. The pathogenic potential of the strains studied was verified by the ability of the strains to invade human gut epithelial cells (Caco-2), as well as to survive in human macrophages (U-937). The virulence of eight S. flexneri strains, representative of the decades analyzed, was evaluated using the Galleria mellonella infection model. The phylogeny of the 50 strains was verified by Multilocus Sequence Typing (MLST). The percentage of invasion in Caco-2 cells was ≥ 40

AIMS:Analyze the survival and transcriptional response of Salmonella Infantis (S. Infantis) against acid, oxidative, increased osmolarity, and thermal stresses. METHODS AND RESULTS:25 strains isolated from human, food, and veterinary sources in Brazil between 2013 and 2018 were analyzed. 8 log10 CFU ml-1 inoculums were exposed for 10 min, 1 h, or 24 h to acid stress (HCl pH 2.6); oxidative stress (15 mmol l-1 H2O2); NaCl 9%; refrigeration (4°C); freezing (-20°C); and heating (63/74°C). Most strains (n = 22) survived the acid stress after 10 min and 1 h. Strains maintained high populations under oxidative stress (>87.7%) and NaCl 9% (111.4%). No strains survived heating, while refrigeration prevented multiplication (∼101%), and freezing reduced populations (<92.6%). Strain 1143/14 had its transcriptome sequenced under acid and oxidative stresses and NaCl 9%. 14 up-regulated and 38 down-regulated transcripts under acid stress, and 407 up-regulated and 143 down-regulated under oxidative stress were expressed, associated with biological processes of response and adaptation. No transcripts were differentially expressed with NaCl 9%. CONCLUSIONS:Salmonella Infantis survival against most stresses represents a challenge for its control. The efficacy of heating reinforced its importance to control Salmonella in food. While acid survival involved the expression of virulence and broad stress response genes, oxidative stress survival showed the expression of genes specific to the adaptation to this condition.

Aeromonas hydrophila and A. dhakensis are ubiquitous microorganisms, widespread in aquatic environments, and can cause severe infections in humans and animals. This study aimed to determine the diversity of virulence genes aerA, hlyA, act, and alt through polymerase chain reaction and the antimicrobial resistance through disk diffusion test of 101 A. hydrophila and 34 A. dhakensis strains from environmental, animal, and human sources gathered between 2016 and 2019 at the National Reference Laboratory for Enteric Diseases. Overall, the virulence gene distribution was act in 35.5% of the samples, alt in 40.7%, aerA in 42.2%, and hlyA in 44.5%. Our results revealed that 76.3% of the 135 isolated Aeromonas exhibited at least one of the genes above. 76.3% of A. hydrophila and 76.5% of A. dhakensis exhibited virulence genes distributed among 15 and 12 virulence profiles, respectively. Antimicrobial resistance was observed in 86% of the strains (87.1% in A. hydrophila and 82.4% in A. dhakensis), with higher rates of resistance to Nalidixic acid (69.3%), Imipenem (31.1%), and Sulfamethoxazole-trimethoprim (15.5%). The occurrence of virulence genes and antimicrobial resistance in A. hydrophila and A. dhakensis from different sources indicates their diversity and pathogenicity, reinforcing that they can be a potential health risk source.

Non-typhoid Salmonella enterica (NTS) serovars Enteritidis (S. Enteritidis), Infantis (S. Infantis), and Typhimurium (S. Typhimurium) are among the main pathogens causing foodborne diseases in humans worldwide. Considering their broad presence in several hosts, including plants, and their increasing antimicrobial resistance rates globally, methods to control spoilage and eradicate these pathogens are necessary. Antimicrobial photodynamic treatment (APDT) shows promising results for the control of foodborne pathogens, but only few studies have analyzed the potential of this method to control NTS, especially among isolates from vegetal sources. Therefore, this study evaluated the effect of APDT with new methylene blue N (NMBN) against planktonic cells and biofilms of S. Enteritidis, S. Infantis, and S. Typhimurium isolated from vegetal sources in Brazil. The eight strains were exposed to APDT with 6.25, 12.5, and 25 μM of NMBN and 4.16, 12.5, and 25 J/cm2 light fluences (5, 15 and 30 min, respectively) for planktonic cells. Two S. Enteritidis and one S. Infantis strains with consistent biofilm formation on crystal-violet staining assay and confocal microscopy were selected for the anti-biofilm APDT under the same conditions. For planktonic cells, 12.5 or 25 μM NMBN with 15 and 30 min exposures fully eradicated all strains tested. For biofilms, these conditions reduced cell counts for all strains, showing that APDT is effective in controlling biofilms. In conclusion, APDT with NMBN was capable of successfully eradicating planktonic cells of S. Enteritidis, S. Infantis, and S. Typhimurium, and also reduced cell counts of S. Enteritidis and S. Infantis biofilms. These results showed the promising capacity of APDT treatment with NMBN as a method for the control and eradication of NTS in food items.

Background/Objectives: Salmonella Saintpaul (SSa) is increasingly linked to foodborne outbreaks in Brazil and globally. Despite its rising public health significance, its epidemiology, genomic diversity, and pathogenic potential remain underexplored. This study addresses these gaps through a comprehensive global analysis of SSa population dynamics, outbreak patterns, and genetic structures, along with an in-depth phenotypic and genomic characterization of strain PP_BR059, isolated from a hospitalized patient in Ceará, Brazil. Methods: We analyzed 1,953 publicly available SSa genomes using core-genome multi-locus sequence typing (cgMLST), antimicrobial resistance (AMR) profiling, pan-genome analysis, and phylogenetic inference. A genome-wide association study (GWAS) identified genetic determinants of virulence and AMR. The invasiveness and intracellular survival of PP_BR059 were assessed using in vitro macrophage infection assays, while whole-genome sequencing (WGS) provided genetic insights. Results: Phylogenetic analysis identified 49 sequence types (STs), with ST-50 (787 genomes) and ST-27 (634 genomes) being most prevalent. ST-50 included all clinical strains from South America, including PP_BR059. AMR analysis showed 60% of SSa genomes were pan-susceptible, while ST-27 had the highest proportion of AMR strains. GWAS revealed distinct evolutionary lineages within ST-50 and ST-27. PP_BR059 exhibited lower macrophage invasion (3.82%) but significantly higher intracellular survival at 2 h (68.72%) and 20 h (25.68%) post-infection. WGS confirmed a pan-susceptible AMR profile and plasmid absence. Conclusions: This study highlights SSa’s global dissemination, evolutionary trends, and pathogenic variability, emphasizing the need for molecular surveillance to inform public health interventions.

Non-typhoid Salmonella are among the main causes of foodborne diseases worldwide. However, information on rare serovars is scarce, limiting the understanding of their prevalence, distribution and pathogenesis. Salmonella enterica serovar Inganda (S. Inganda) is a rare non-typhoid serovar. Considering the few existing reports, and the current use of genomics, this study characterized for the first time the antimicrobial resistance, pathogenic potential and diversity of S. Inganda genomes worldwide. A S. Inganda strain from human feces in 2018 in Brazil (SI264) had its resistance determined against 18 antimicrobials by disk-diffusion and had its genome sequenced. S. Inganda publicly available genomes (n = 12) were analyzed for genotypic resistance, stress and virulence genes, plasmids, pathogenicity islands, prophages, Multi-Locus Sequence Typing (MLST), core-genome MLST (cgMLST), and single-nucleotide polymorphisms (SNPs). SI264 showed no phenotypic resistance. All 12 S. Inganda genomes harbored genes or mutations for aminoglycoside (aac(6’)-Iaa), quinolone (parC Thr57→Ser), and acid (asr) resistance, multi-drug efflux systems (mdsAB), and gold tolerance (golST). One genome from US harbored pKPC-CAV1321 plasmid. Nine pathogenicity islands, 174 Salmonella virulence genes, and 17 prophages were found in different frequencies. Although a great genomic diversity was noticed, S. Inganda genomes from US and UK were closely related. In conclusion, genomic analyses were able to characterize the current available genomes of S. Inganda strains mostly as genetically diverse, susceptible to antimicrobials, and potentially acid and heavy metal resistant. The presence of numerous virulence features also suggested their pathogenic potential, especially among clinical strains, and reinforced the importance to better characterize rare non-typhoid serovars.

Due to their biological characteristics, elasmobranchs are highly vulnerable to overfishing and habitat degradation. Environmental pollution has also been shown to increasingly affect elasmobranch microbiota composition, yet studies in this area remain scarce. This study aimed to provide a baseline assessment of enteric bacterial species detected in various shark and ray species from the Brazilian Amazon Coast. Enterobacteria samples were collected through cloacal smears from elasmobranchs, cultured, isolated, and biochemically identified (e.g., Vibrio, Aeromonas, Enterobacterales). Polymerase chain reaction (PCR) assays were conducted to identify Aeromonas spp. pathotypes. The most frequently detected enteric bacteria were Klebsiella pneumoniae (47

Introduction. Salmonella 1,4, [5],12:i:- strains with different antimicrobial resistance profiles have been associated with foodborne disease outbreaks in several countries. In Brazil, S . 1,4, [5],12:i:- was identified as one of the most prevalent serovars in São Paulo State during 2004–2020. Gap Statement. However, few studies have characterized this serovar in Brazil. Aim. This study aimed to determine the antimicrobial resistance profiles of S . 1,4, [5],12:i:- strains isolated from different sources in Southeast Brazil and compare their genetic diversity. Methodology. We analysed 113 S . 1,4, [5],12:i:- strains isolated from humans ( n =99), animals ( n =7), food ( n =5) and the environment ( n =2) between 1983 and 2020. Susceptibility testing against 13 antimicrobials was performed using the disc diffusion method for all the strains. Plasmid resistance genes and mutations in the quinolone resistance-determining regions were identified in phenotypically fluoroquinolone-resistant strains. Molecular typing was performed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for all strains and multilocus sequence typing (MLST) for 40 selected strains. Results. Of the 113 strains, 54.87 % were resistant to at least one antimicrobial. The highest resistance rates were observed against ampicillin (51.33 %), nalidixic acid (39.82 %) and tetracycline (38.05 %). Additionally, 39 (34.51 %) strains were classified as multidrug-resistant (MDR). Nine fluoroquinolone-resistant strains exhibited the gyrA mutation (Ser96→Tyr96) and contained the qnrB gene. The 113 strains were grouped into two clusters using ERIC-PCR, and most of strains were present in one cluster, with a genetic similarity of ≥80 %. Finally, 40 strains were typed as ST19 using MLST. Conclusion. The prevalence of MDR strains is alarming because antimicrobial treatment against these strains may lead to therapeutic failure. Furthermore, the ERIC-PCR and MLST results suggested that most strains belonged to one main cluster. Thus, a prevalent subtype of Salmonella 1,4, [5],12:i:- strains has probably been circulating among different sources in São Paulo, Brazil, over decades.

Introduction. Salmonella 1,4, [5],12:i:- strains with different antimicrobial resistance profiles have been associated with foodborne disease outbreaks in several countries. In Brazil, S. 1,4, [5],12:i:- was identified as one of the most prevalent serovars in São Paulo State during 2004–2020. Gap Statement. However, few studies have characterized this serovar in Brazil. Aim. This study aimed to determine the antimicrobial resistance profiles of S. 1,4, [5],12:i:- strains isolated from different sources in Southeast Brazil and compare their genetic diversity. Methodology. We analysed 113 S. 1,4, [5],12:i:- strains isolated from humans (n=99), animals (n=7), food (n=5) and the environment (n=2) between 1983 and 2020. Susceptibility testing against 13 antimicrobials was performed using the disc diffusion method for all the strains. Plasmid resistance genes and mutations in the quinolone resistance-determining regions were identified in phenotypically fluoroquinolone-resistant strains. Molecular typing was performed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for all strains and multilocus sequence typing (MLST) for 40 selected strains. Results. Of the 113 strains, 54.87 % were resistant to at least one antimicrobial. The highest resistance rates were observed against ampicillin (51.33 %), nalidixic acid (39.82 %) and tetracycline (38.05 %). Additionally, 39 (34.51 %) strains were classified as multidrug-resistant (MDR). Nine fluoroquinolone-resistant strains exhibited the gyrA mutation (Ser96→Tyr96) and contained the qnrB gene. The 113 strains were grouped into two clusters using ERIC-PCR, and most of strains were present in one cluster, with a genetic similarity of ≥80 %. Finally, 40 strains were typed as ST19 using MLST. Conclusion. The prevalence of MDR strains is alarming because antimicrobial treatment against these strains may lead to therapeutic failure. Furthermore, the ERIC-PCR and MLST results suggested that most strains belonged to one main cluster. Thus, a prevalent subtype of Salmonella 1,4, [5],12:i:- strains has probably been circulating among different sources in São Paulo, Brazil, over decades.

Background Salmonella enterica serovar Infantis (Salmonella Infantis) is a zoonotic, ubiquitous and foodborne pathogen of worldwide distribution. Despite Brazil’s relevance as a major meat exporter, few studies were conducted to characterize strains of this serovar by genomic analyses in this country. Therefore, this study aimed to assess the diversity of 80 Salmonella Infantis strains isolated from veterinary, food and human sources in Brazil between 2013 and 2018 by comparative genomic analyses. Additional genomes of non-Brazilian countries (n = 18) were included for comparison purposes in some analyses. Methods Analyses of whole-genome multi-locus sequence typing (wgMLST), using PGAdb-builder, and of fragmented genomes, using Gegenees, were conducted to compare the 80 Brazilian strains to the 18 non-Brazilian genomes. Pangenome analyses and calculations were performed for all Salmonella Infantis genomes analyzed. The presence of prophages was determined using PHASTER for the 80 Brazilian strains. The genome plasticity using BLAST Ring Image Generator (BRIG) and gene synteny using Mauve were evaluated for 20 selected Salmonella Infantis genomes from Brazil and ten from non-Brazilian countries. Unique orthologous protein clusters were searched in ten selected Salmonella Infantis genomes from Brazil and ten from non-Brazilian countries. Results wgMLST and Gegenees showed a high genomic similarity among some Brazilian Salmonella Infantis genomes, and also the correlation of some clusters with non-Brazilian genomes. Gegenees also showed an overall similarity >91% among all Salmonella Infantis genomes. Pangenome calculations revealed an open pangenome for all Salmonella Infantis subsets analyzed and a high gene content in the core genomes. Fifteen types of prophages were detected among 97.5% of the Brazilian strains. BRIG and Mauve demonstrated a high structural similarity among the Brazilian and non-Brazilian isolates. Unique orthologous protein clusters related to biological processes, molecular functions, and cellular components were detected among Brazilian and non-Brazilian genomes. Conclusion The results presented using different genomic approaches emphasized the significant genomic similarity among Brazilian Salmonella Infantis genomes analyzed, suggesting wide distribution of closely related genotypes among diverse sources in Brazil. The data generated contributed to novel information regarding the genomic diversity of Brazilian and non-Brazilian Salmonella Infantis in comparison. The different genetically related subtypes of Salmonella Infantis from Brazil can either occur exclusively within the country, or also in other countries, suggesting that some exportation of the Brazilian genotypes may have already occurred.

Salmonella enterica serovar Infantis (S. Infantis) is a globally distributed non-typhoid serovar infecting humans and food-producing animals. Considering the zoonotic potential and public health importance of this serovar, strategies to characterizing, monitor and control this pathogen are of great importance. This study aimed to determine the genetic relatedness of 80 Brazilian S. Infantis genomes in comparison to 40 non-Brazilian genomes from 14 countries using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR–Multi-Locus Virulence Sequence Typing (CRISPR–MVLST). CRISPR spacers were searched using CRISPR-Cas++ and fimH and sseL alleles using BLAST and MEGA X. Results were analyzed using BioNumerics 7.6 in order to obtain similarity dendrograms. A total of 23 CRISPR1 and 11 CRISPR2 alleles formed by 37 and 26 types of spacers, respectively, were detected. MVLST revealed the presence of five fimH and three sseL alleles. CRISPR’s similarity dendrogram showed 32 strain subtypes, with an overall similarity ≥ 78.6. The CRISPR–MVLST similarity dendrogram showed 37 subtypes, with an overall similarity ≥ 79.2. In conclusion, S. Infantis strains isolated from diverse sources in Brazil and other countries presented a high genetic similarity according to CRISPR and CRISPR–MVLST, regardless of their source, year, and/or place of isolation. These results suggest that both methods might be useful for molecular typing S. Infantis strains using WGS data.

Salmonella Minnesota has emerged in Brazil as the predominant serovar in poultry and poultry products, along with Salmonella Heidelberg. To understand the emergence of Salmonella Minnesota over the last few years in Brazil, we performed a comparative analysis between 69 selected S . Minnesota genomes from Pathogen Detection database and 65 clonal emergent genomes isolated from Brazil. We demon strate the presence of multidrug resistance genes against tetracycline [tet(A)], sulfona mide (sul2), and AmpC beta-lactamase (blaCMY-2) in emergent genomes, along with the carriage of a megaplasmid of resistance and virulence (similar to 210 kb), designated pESM (plasmid for emergent Salmonella Minnesota). pESM is an IncC/A2 plasmid predicted to increase S . Minnesota environmental tolerance to mercury ( mer operon) and provide resistance to tetracycline and ampicillin due to the presence of tet (A) and bla CMY-2 , respectively. Moreover, pESM carries the yersiniabactin siderophore (high-pathogenicity island of Yersinia) related to the iron uptake. The temporal inference demonstrated that the most recent common ancestor dated from similar to 1978 and that the clonal emergent genomes carrying the pESM belong to a completely different lineage of S . Minnesota. Our results indicate that the presence of pESM likely contributes to the emergence of S . Minnesota and is precisely related to the successful spread of this particular clonal lineage in Brazil.

Introduction. Salmonella 1,4, [5],12:i:- strains with different antimicrobial resistance profiles have been associated with foodborne disease outbreaks in several countries. In Brazil, S. 1,4, [5],12:i:- was identified as one of the most prevalent serovars in São Paulo State during 2004-2020.Gap Statement. However, few studies have characterized this serovar in Brazil.Aim. This study aimed to determine the antimicrobial resistance profiles of S. 1,4, [5],12:i:- strains isolated from different sources in Southeast Brazil and compare their genetic diversity.Methodology. We analysed 113 S. 1,4, [5],12:i:- strains isolated from humans (n=99), animals (n=7), food (n=5) and the environment (n=2) between 1983 and 2020. Susceptibility testing against 13 antimicrobials was performed using the disc diffusion method for all the strains. Plasmid resistance genes and mutations in the quinolone resistance-determining regions were identified in phenotypically fluoroquinolone-resistant strains. Molecular typing was performed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for all strains and multilocus sequence typing (MLST) for 40 selected strains.Results. Of the 113 strains, 54.87 % were resistant to at least one antimicrobial. The highest resistance rates were observed against ampicillin (51.33 %), nalidixic acid (39.82 %) and tetracycline (38.05 %). Additionally, 39 (34.51 %) strains were classified as multidrug-resistant (MDR). Nine fluoroquinolone-resistant strains exhibited the gyrA mutation (Ser96→Tyr96) and contained the qnrB gene. The 113 strains were grouped into two clusters using ERIC-PCR, and most of strains were present in one cluster, with a genetic similarity of ≥80 %. Finally, 40 strains were typed as ST19 using MLST.Conclusion. The prevalence of MDR strains is alarming because antimicrobial treatment against these strains may lead to therapeutic failure. Furthermore, the ERIC-PCR and MLST results suggested that most strains belonged to one main cluster. Thus, a prevalent subtype of Salmonella 1,4, [5],12:i:- strains has probably been circulating among different sources in São Paulo, Brazil, over decades.

Introduction. Salmonella 1,4, [5],12:i:- strains with different antimicrobial resistance profiles have been associated with foodborne disease outbreaks in several countries. In Brazil, S. 1,4, [5],12:i:- was identified as one of the most prevalent serovars in S & atilde;o Paulo State during 2004-2020. Gap Statement. However, few studies have characterized this serovar in Brazil. Aim. This study aimed to determine the antimicrobial resistance profiles of S. 1,4, [5],12:i:- strains isolated from different sources in Southeast Brazil and compare their genetic diversity. Methodology. We analysed 113 S. 1,4, [5],12:i:- strains isolated from humans (n=99), animals (n=7), food (n=5) and the environment (n=2) between 1983 and 2020. Susceptibility testing against 13 antimicrobials was performed using the disc diffusion method for all the strains. Plasmid resistance genes and mutations in the quinolone resistance- determining regions were identified in phenotypically fluoroquinolone- resistant strains. Molecular typing was performed using enterobacterial repetitive intergenic consensus PCR (ERIC- PCR) for all strains and multilocus sequence typing (MLST) for 40 selected strains. Results. Of the 113 strains, 54.87 % were resistant to at least one antimicrobial. The highest resistance rates were observed against ampicillin (51.33 %), nalidixic acid (39.82 %) and tetracycline (38.05 %). Additionally, 39 (34.51 %) strains were classified as multidrug- resistant (MDR). Nine fluoroquinolone- resistant strains exhibited the gyrA mutation (Ser96 -> Tyr96) and contained the qnrB gene. The 113 strains were grouped into two clusters using ERIC- PCR, and most of strains were present in one cluster, with a genetic similarity of >= 80 %. Finally, 40 strains were typed as ST19 using MLST. Conclusion. The prevalence of MDR strains is alarming because antimicrobial treatment against these strains may lead to therapeutic failure. Furthermore, the ERIC- PCR and MLST results suggested that most strains belonged to one main cluster. Thus, a prevalent subtype of Salmonella 1,4, [5],12:i:- strains has probably been circulating among different sources in S & atilde;o Paulo, Brazil, over decades.

AIMS:Although elasmobranchs are consumed worldwide, bacteriological assessments for this group are still sorely lacking. In this context, this study assessed bacteria of sharks and rays from one of the most important landing ports along the Rio de Janeiro coast.METHODS AND RESULTS:Bacteria were isolated from the cloacal swabs of the sampled elasmobranchs. They were cultured, and Vibrio, Aeromonas, and Enterobacterales were isolated and identified. The isolated bacteria were then biochemically identified and antimicrobial susceptibility assays were performed. Antigenic characterizations were performed for Salmonella spp. and Polymerase Chain Reaction (PCR) assays were performed to identify Escherichia coli pathotypes. Several bacteria of interest in the One Health context were detected. The most prevalent Enterobacterales were Morganella morganii and Citrobacter freundii, while Vibrio harveyi and Vibrio fluvialis were the most prevalent among Vibrio spp. and Aeromonas allosacharophila and Aeromonas veronii bv. veronii were the most frequent among Aeromonas spp. Several bacteria also displayed antimicrobial resistance, indicative of Public Health concerns. A total of 10% of Vibrio strains were resistant to trimethoprim-sulfamethoxazole and 40% displayed intermediate resistance to cefoxitin. Salmonella enterica strains displayed intermediate resistance to ciprofloxacin, nalidixic acid and streptomycin. All V. cholerae strains were identified as non-O1/non-O139. The detected E. coli strains did not exhibit pathogenicity genes. This is the first study to perform serology assessments for S. enterica subsp. enterica isolated from elasmobranchs, identifying the zoonotic Typhimurium serovar. Salmonella serology evaluations are, therefore, paramount to identify the importance of elasmobranchs in the epidemiological salmonellosis chain.CONCLUSIONS:The detection of several pathogenic and antibiotic-resistant bacteria may pose significant Public Health risks in Brazil, due to high elasmobranch consumption rates, indicating the urgent need for further bacteriological assessments in this group.

Salmonella spp. are known to persist in the environment. Wild animals are believed to act as important reservoirs, with antimicrobial resistance frequently occurring in the environment. However, little is known about the role of the wildlife in Bahia as a reservoir for Salmonella in Brazil. This study aimed to isolate and characterize Salmonella spp. from wildlife in the Atlantic Forest and Caatinga biomes considering indicators such as the animal species, degree of anthropization, sampling area, and feeding habits. Convenience wildlife sampling and characterization were conducted, followed by microbiological and molecular identification of Salmonella isolates, serotyping, and antimicrobial susceptibility testing. A total of 674 fecal samples were collected from 12 municipalities during 2015–2021, and 4 were positive for the following Salmonella species: Salmonella enterica subspecies enterica serovar Agona (n = 1), Salmonella enterica subsp. enterica serogroup O:16 (n = 2), and Salmonella enterica subsp. enterica serovar Muenchen (n = 1). Antimicrobial susceptibility analysis revealed that one isolate was resistant to six antibiotics, including extended-spectrum penicillins and beta-lactamase inhibitors. These results indicated a low frequency of Salmonella spp. in the sampled forest fragments. The presence of Salmonella in wild animals increases the risk to public health and biodiversity and indicates that they can act as sentinels of environmental contamination or indicators of preservation.

Salmonella Isangi is an infrequent serovar that has recently been reported in several countries due to nosocomial infections. A considerable number of reports indicate Salmonella Isangi multidrug resistance, especially to cephalosporins, which could potentially pose a risk to public health worldwide. Genomic analysis is an excellent tool for monitoring the emergence of microorganisms and related factors. In this context, the aim of this study was to carry out a genomic analysis of Salmonella Isangi isolated from poultry in Brazil, and to compare it with the available genomes from the Pathogen Detection database and Sequence Read Archive. A total of 142 genomes isolated from 11 different countries were investigated. A broad distribution of extended-spectrum beta-lactamase (ESBL) genes was identified in the Salmonella Isangi genomes examined (bla(CTX-M-15), bla(CTX-M-2), bla(DHA-1), bla(NDM-1), bla(OXA-10), bla(OXA-1), bla(OXA-48), bla(SCO-1), bla(SHV-5), bla(TEM-131), bla(TEM-1B)), primarily in South Africa. Resistome analysis revealed predicted resistance to aminoglycoside, sulfonamide, macrolide, tetracycline, trimethoprim, phenicol, chloramphenicol, and quaternary ammonium. Additionally, PMQR (plasmid-mediated quinolone resistance) genes qnr19, qnrB1, and qnrS1 were identified, along with point mutations in the genes gyrA(D87N), gyrA(S83F), and gyrB(S464F), which confer resistance to ciprofloxacin and nalidixic acid. With regard to plasmids, we identified 17 different incompatibility groups, including IncC, Col(pHAD28), IncHI2, IncHI2A, IncM2, ColpVC, Col(Ye4449), Col156, IncR, IncI1(Alpha), IncFIB (pTU3), Col(B5512), IncQ1, IncL, IncN, IncFIB(pHCM2), and IncFIB (pN55391). Phylogenetic analysis revealed five clusters grouped by sequence type and antimicrobial gene distribution. The study highlights the need for monitoring rare serovars that may become emergent due to multidrug resistance.

Salmonella enterica serovar Heidelberg ( S . Heidelberg) is a zoonotic, ubiquitous, and worldwide-distributed pathogen, responsible for gastroenteritis in humans caused by the consumption of contaminated food. In this study, 11 S. Heidelberg strains isolated from chicken and bovine meat, drag swab, and animal feed between 2013 and 2017 in states of the southern region of Brazil were characterized by whole-genome sequencing (WGS) analyses. Antimicrobial resistance against 18 antimicrobials was determined by disk-diffusion and ciprofloxacin’s minimum inhibitory concentration by Etest®. The search for resistance and virulence genes, plasmids, Salmonella Pathogenicity Islands (SPIs) plus multi-locus sequence typing (MLST), and single-nucleotide polymorphisms (SNPs) analyses was conducted using WGS data. All strains harbored resistance genes fosA7 , aac(6')-Iaa , sul2 , tet(A) , bla CMY-2 , mdsA , and mdsB , and point mutations in gyrA and parC . All strains showed a phenotypic multidrug-resistant profile, with resistant or intermediate resistant profiles against 14 antimicrobials tested. Plasmids ColpVC, IncC, IncX1, and IncI1-I(Alpha) were detected. Virulence genes related to adherence, macrophage induction, magnesium uptake, regulation, and type III secretion systems plus 10 SPIs were detected. All strains were assigned to ST15 and belonged to two SNP clusters showing high similarity to isolates from the United Kingdom, Chile, Germany, the Netherlands, China, South Africa, and South Korea. In conclusion, the presence of multidrug-resistant S. Heidelberg strains in Brazil showing a global genomic relationship may alert for the necessity of stronger surveillance measures by food safety and public health authorities to limit its spread to humans and animals through foods.