Prevalence, antimicrobial resistance and genomic comparison of non-typhoidal salmonella isolated from pig farms with different levels of intensification in Yangon Region, Myanmar.

In Myanmar, where backyard, semi-intensive, and intensive pig (Sus scrofa domesticus) farming coexist, there is limited understanding of the zoonotic risks and antimicrobial resistance (AMR) associated with these farming practices. This study was conducted to investigate the prevalence, AMR and genomic features of Salmonella in pig farms in the Yangon region and the impact of farm intensification to provide evidence to support risk-based future management approaches. Twenty-three farms with different production scales were sampled for two periods with three sampling-visit each. Antimicrobial susceptibility tests and whole-genome sequencing were performed on the isolates. The prevalence of Salmonella was 44.5% in samples collected from backyard farms, followed by intensive (39.5%) and semi-intensive farms (19.5%). The prevalence of multi-drug resistant isolates from intensive farms (45/84, 53.6%) was higher than those from backyard (32/171, 18.7%) and semi-intensive farms (25/161, 15.5%). Among 28 different serovars identified, S. Weltevreden (40; 14.5%), S. Kentucky (38; 13.8%), S. Stanley (35, 12.7%), S. Typhimurium (22; 8.0%) and S. Brancaster (20; 7.3%) were the most prevalent serovars and accounted for 56.3% of the genome sequenced strains. The diversity of Salmonella serovars was highest in semi-intensive and backyard farms (21 and 19 different serovars, respectively). The high prevalence of globally emerging S. Kentucky ST198 was detected on backyard farms. The invasive-infection linked typhoid-toxin gene (cdtB) was found in the backyard farm isolated S. Typhimurium, relatively enriched in virulence and AMR genes, presented an important target for future surveillance. While intensification, in terms of semi-intensive versus backyard production, maybe a mitigator for zoonotic risk through a lower prevalence of Salmonella, intensive production appears to enhance AMR-associated risks. Therefore, it remains crucial to closely monitor the AMR and virulence potential of this pathogen at all scales of production. The results underscored the complex relationship between intensification of animal production and the prevalence, diversity and AMR of Salmonella from pig farms in Myanmar.

Evaluation of lyophilized bacteriophage cocktail efficiency against multidrug-resistant Salmonella in broiler chickens.

Currently, phage biocontrol is increasingly used as a green and natural technology for treating Salmonella and other infections, but phages exhibit instability and activity loss during storage. Therefore, in this study, the effects of lyophilization on the activity and stability of phage cocktails for the control of multidrug-resistant Salmonella in broiler chickens were determined. Eight serotypes of Salmonella were isolated and identified from broiler chicken farms, and bacteriophages against multidrug-resistant Salmonella enterica subsp. enterica serovar Kentucky, Salmonella enterica subsp. enterica serovar Typhimrium and Salmonella enterica subsp. enterica serovar Enteritidis were isolated. The bacteriophage cocktail was prepared and lyophilized, and it was subjected to in vitro and in vivo examinations. A reconstituted lyophilized bacteriophage cocktail was used for the oral treatment of chicks before and after challenge with multidrug-resistant S. Kentucky. The colonization of cecum by S. Kentucky was detected by using real-time PCR, and the serum levels of IgM, IgA and IL-4 and pathological changes in the different groups were detected. Three Caudovirales phages families were identified including Autographiviridae, Straboviridae and Drexlerviridae against multidrug-resistant S. Kentucky, S. Typhimrium and S. Enteritidis. The groups treated with the bacteriophage cocktail showed no clinical signs, no postmortem lesions, and a mortality rate of 0%, which improved the growth performance parameters. Additionally, the estimated serum levels of IgM, IgA and IL-4 were significantly greater in the bacteriophage cocktail-treated groups. Lyophilization effectively preserves the long-term storage stability of phages. Therefore, lyophilized bacteriophage cocktail therapy is a valuable approach for controlling multidrug-resistant Salmonella infections in broiler chickens.

Bacterial Prostatitis Secondary to Salmonella enterica serovar Enteritidis in an Immunocompetent Dog.

Salmonella is a rod-shaped gram-negative bacterium of the family Enterobacteriaceae, commonly present in the gastrointestinal tract in humans and animals. Salmonella-associated bacteriuria and prostatitis are rare but have been reported in humans, predominantly older patients with underlying diseases, including urinary tract obstructions, diabetes mellitus, and compromised immunity. In dogs, Salmonella bacteriuria and prostatitis have only been described in patients on immunosuppressive medications. This study reports the case of a 7 yr old male Pit bull terrier mix with Salmonella prostatitis. The patient had a 3 day history of lethargy and anorexia. He was fed a commercial diet and had no previous medical or medication history. On physical examination, he had caudal abdominal pain and a firm, enlarged, painful prostate. Ultrasound revealed marked prostatomegaly with multifocal echogenic fluid-filled cavitations and regional peritonitis. Urine and prostatic fluid culture grew Salmonella (>100,000 colony-forming units/mL) using standard culture methods. Treatment with enrofloxacin was initiated for 8 wk. Repeat urine and prostatic cultures after cessation of antibiotics were negative, and serial fecal cultures were Salmonella negative. This case report is, to the best of our knowledge, the first to describe Salmonella prostatitis and bacteriuria in an immunocompetent dog who was not fed a raw diet.

Low-cost biosecurity measures are associated with reduced detection of non-Typhoidal Salmonella in Nigerian poultry while inappropriate antibiotic use is widespread.

Large-scale poultry production in low- and middle-income countries may be a source of adulterated products (e.g., Salmonella contamination, antibiotic residues) that can be disseminated over wide areas. We employed a cross-sectional survey of 199 randomly selected poultry farms in Lagos State, Nigeria, to estimate the prevalence of non-typhoidal Salmonella (NTS), and biosecurity and antibiotic use practices. Pooled fecal samples were collected from laying chickens and from poultry handlers. Selective culture, biochemical assays, and PCR (invA) were used to isolate and confirm NTS isolates. NTS was detected at 14% of farms (28/199) and from 10% of farm workers (6/60). Multivariate logistic regression analysis indicated that antiseptic foot dips reduced the odds ratio (OR) for detecting NTS in chicken feces [OR: 0.55; 95% confidence interval (CI) 0.07-0.58]. Most farms (94.5%, 188/199) used antibiotics for treatment and prophylaxis, but no farms (0/199) exercised withdrawal before sale of products. Most farms (86.4%, 172/199) reported using antibiotic cocktails that included medically important colistin, ciprofloxacin, chloramphenicol, and gentamicin. Egg production in Lagos State relies heavily on antibiotics and antibiotic residues are likely passed to consumers through poultry products, but there is evidence that low-cost biosecurity controls are effective for limiting the presence of NTS on farms.

Deletions of ttrA and pduA genes in Salmonella enterica affect survival within chicken-derived HD-11 macrophages.

In mammals, enteric salmonellas can use tetrathionate (ttr), formed as a by-product from the inflammatory process in the intestine, as electron acceptor in anaerobic respiration, and it can fuel its energy metabolism by degrading the microbial fermentation product 1,2-propanediol. However, recent studies have shown that this mechanism is not important for Salmonella infection in the intestine of poultry, while it prolongs the persistence of Salmonella at systemic sites in this species. In the current study, we show that ΔttrApduA strains of Salmonella enterica have lower net survival within chicken-derived HD-11 macrophages, as CFU was only 2.3% (S. Enteritidis ΔttrApduA), 2.3% (S. Heidelberg ΔttrApduA), and 3.0% (S. Typhimurium ΔttrApduA) compared to wild-type strains after 24 h inside HD-11 macrophage cells. The difference was not related to increased lysis of macrophages, and deletion of ttrA and pduA did not impair the ability of the strains to grow anaerobically. Further studies are indicated to determine the reason why Salmonella ΔttrApduA strains survive less well inside macrophage cell lines.

Emergence and Comparative Genome Analysis of Salmonella Ohio Strains from Brown Rats, Poultry, and Swine in Hungary.

Rats are particularly important from an epidemiological point of view, because they are regarded as reservoirs for diverse zoonotic pathogens including enteric bacteria. This study is the first to report the emergence of Salmonella serovar Ohio in brown rats (Rattus norvegicus) and food-producing animals in Hungary. We first reveal the genomic diversity of the strains and their phylogenomic relationships in the context of the international collection of S. Ohio genomes. This pathogen was detected in 4.3% (4/92) of rats, captured from multiple sites in Hungary. A whole-genome-based genotype comparison of S. Ohio, Infantis, Enteritidis, and Typhimurium strains showed that 76.4% (117/153) of the virulence and antimicrobial resistance genes were conserved among these serovars, and none of the genes were specific to S. Ohio. All S. Ohio strains lacked virulence and resistance plasmids. The cgMLST phylogenomic comparison highlighted a close genetic relationship between rat and poultry strains of S. Ohio from Hungary. These strains clustered together with the international S. Ohio genomes from aquatic environments. Overall, this study contributes to our understanding of the epidemiology of Salmonella spp. in brown rats and highlights the importance of monitoring to minimize the public health risk of rodent populations. However, further research is needed to understand the route of infection and evolution of this serovar.

Intravaginally CpG-ODN and Salmonella enteritidis on TLR21, cytokines, and AvBD10 gene expressions in the reproductive tract of native chicken.

Salmonella enterica subsp. enterica serovar Enteritidis (SE) is a global concern for the poultry industry due to its association with foodborne illnesses. The transmission occurs through the transovarial route which initiates from colonization in oviducts and ascending to ovaries. Though there are studies on cytosine-phosphate-guanine oligodeoxynucleotide (CpG-ODN) and the increase of innate immune response, there is limited research on the intravaginal treatment using CpG-ODN. Previous studies have shown that stimulating CpG-ODN can induce the production of antimicrobial peptide avian beta-defensins (AvBDs) in vaginal cell cultures, there is limited information on the use of intravaginal treatment to induce the innate immune system, particularly in the Kampung Unggul Balitbangtan (KUB-1) chickens (Gallus gallus domesticus). This study investigates the impact of intravaginal CpG-ODN stimulation on the innate immune response in KUB-1 chicken ovaries and oviducts when challenged to SE. A total of 39 KUB-1 chickens were divided into four groups namely T1 (treated with CpG-ODN, n=12), T2 (SE group, n=12), T3 (CpG-ODN and SE, n=12), and Control (without CpG-ODN and SE, n=3). Chickens were observed from day 1 to 4 post-intravaginal (PI) inoculation. The results suggest that intravaginal CpG-ODN treatment modulates AvBD10 production through toll-like receptor (TLR)21, with interleukin (IL)1B and IL10 playing reciprocal roles, providing insights into the potential of this treatment to prevent transovarial Salmonellosis in poultry. The novelty of this study adds valuable insights to the current body of knowledge.

Salmonella Prevalence and antibiotic resistance profile in raw poultry meat sold in North Lebanon: Insights from the COVID-19 pandemic and economic crisis.

Salmonella-related foodborne illness is a significant public health concern, with the primary source of human infection being animal-based food products, particularly chicken meat. Lebanon is currently experiencing a dual crisis: the COVID-19 pandemic and an unprecedented economic crisis, which has resulted in substantial challenges to the public health system and food safety. This study aims to assess the prevalence and antibiotic resistance profile of Salmonella in raw poultry meat sold in North Lebanon during this dual crisis. A cross-sectional study was carried out between May 2021 and April 2022 across six different districts in North Lebanon. A total of 288 whole, unprocessed chickens were examined. The isolation and identification of Salmonella isolates were done based on cultural and biochemical properties. All isolates were subjected to antimicrobial susceptibility testing and phenotypic assays for Extended-Spectrum Beta-lactamase (ESBL) detection. The prevalence of Salmonella in raw poultry meat purchased in North Lebanon reached 18.05 % (52/288). The dry season and chilled chicken were significantly associated with an increased risk of Salmonella contamination (P < 0.05). Additionally, 34.61 % of the isolates were potential ESBL producers, and 57.69 % exhibited multidrug resistance (MDR). This study highlights the existence of MDR in chicken meat in North Lebanon, posing a potential health risk if undercooked chicken meat is consumed. This emphasizes the importance of the implementation of preventive strategies and hygienic procedures throughout the food chain to reduce the risk of Salmonella spp. contamination in chicken meats and its potential transmission to humans.

Effect of Phage Spray on Hatchability and Chick Quality of Eggs Contaminated with Salmonella Typhimurium.

Salmonella Typhimurium (S. Typhimurium) contamination poses a significant challenge to breeder egg hatchability and chick health, necessitating the exploration of alternative disinfection methods. This study investigates the potential of phage vB_SPuM_SP02 (SP02) as a novel disinfectant for breeder eggs contaminated with S. Typhimurium SM022. Phage SP02 was isolated from poultry farm effluent and characterized for morphology, biological properties, and genome properties. Experimental groups of specific pathogen-free (SPF) eggs were treated with Salmonella and phage SP02, and efficacy was assessed through hatching rates, chick survival, weight, Salmonella load, immune organ indices, and intestinal flora. Phage treatment effectively eradicated Salmonella contamination on eggshells within 12 h, resulting in increased hatching and survival rates compared to controls. Furthermore, phage treatment mitigated weight loss and tissue Salmonella load in chicks without causing immune organ damage while reducing Salmonella spp. abundance in the intestinal tract. This study demonstrates the potential of phage SP02 as an eco-friendly and efficient disinfectant for S. Typhimurium-contaminated breeder eggs, offering promising prospects for practical application in poultry production.

Insights into the global genomic features of Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum.

AIMS: Characterize global genomic features of 86 genomes of Salmonella Gallinarum (SG) and Pullorum (SP), which are important pathogens causing systemic infections in poultry. METHODS AND RESULTS: All genomes harbored efflux pump encoding gene mdsA and gold tolerance genes golS and golT. Aminoglycoside (aac(6')-Ib, aadA5, aph(6)-Id, aph(3'')-Ib, ant(2'')-Ia), beta-lactam (blaTEM-1, blaTEM-135), efflux pump (mdsB), fosfomycin (fosA3), sulfonamide (sul1, sul2), tetracycline [tet(A)], trimethoprim (dfrA17), acid (asr), and disinfectant (qacEdelta1) resistance genes, gyrA, gyrB, and parC quinolone resistance point mutations, and mercury tolerance genes (mer) were found in different frequencies. Additionally, 310 virulence genes, pathogenicity islands (including SPI-1, 2, 3, 4, 5, 6, 9, 10, 12, 13, and 14), plasmids [IncFII(S), ColpVC, IncX1, IncN, IncX2, and IncC], and prophages (Fels-2, ST104, 500465-1, pro483, Gifsy-2, 103 203_sal5, Fels-1, RE-2010, vB_SenS-Ent2, and L-413C) were detected. MLST showed biovar-specific sequence types, and core genome MLST showed country-specific and global-related clusters. CONCLUSION: SG and SP global strains carry many virulence factors and important antimicrobial resistance genes. The diverse plasmids and prophages suggest genetic variability. MLST and cgMLST differentiated biovars and showed profiles occurring locally or worldwide.

Generation and evaluation of Salmonella entericaserovar Choleraesuis mutant strains as a potential live-attenuated vaccine.

BACKGROUND: Salmonella entericaserovar Choleraesuis (S.C) is a swine enteric pathogen causing paratyphoid fever, enterocolitis, and septicemia in piglets. S. C is mainly transmitted through the fecal-oral route. Vaccination is an effective strategy for preventing and controlling Salmonella infection. RESULTS: Herein, we used CRISPR-Cas9 technology to knockout the virulence regulatory genes, rpoS, and slyA of S. C and constructed the ∆rpoS, ∆slyA, and ∆rpoS ∆slyA strains. The phenotypic characteristics of the mutant strains remained unchanged compared with the parental wild-type strain. In vivo study, unlike the wild-type strain, the ∆slyA and ∆rpoS ∆slyA strains alleviated splenomegaly, colon atrophy, and lower bacterial loads in the spleen, liver, ileum, and colon. These mutant strains survived in Peyer's patches (PPs) and mesenteric lymph nodes (MLN) for up to 15 days post-infection. Furthermore, the immunization of the ∆rpoS ∆slyA strain induced robust humoral and cellular immune responses. CONCLUSIONS: Consequently, vaccination with ∆rpoS ∆slyA conferred a high percentage of protection against lethal invasive Salmonella, specifically S. C, in mice. This study provided novel insights into the development of live-attenuated vaccines against the infection of S. C.

Risk factors for the introduction of Salmonella spp. serogroups B and D into Dutch dairy herds.

Salmonella spp. infections in animals are a concern due to their zoonotic nature, welfare effects and economic impact on the livestock industry. To enable targeted surveillance, it is important to identify risk factors for the introduction of Salmonella spp. in a herd. Since 2009, Dutch dairy processors require herds delivering milk to their plants to participate in a Salmonella programme. In this programme, bulk milk is tested three times a year (i.e. test rounds) by ELISA on presence of antibodies against Salmonella spp. serogroups B and D. Based on these bulk milk results we identified newly infected herds, and aimed to identify associated risk factors. Effects of putative risk factors for becoming newly infected were studied using a multivariable population average logistic regression (PA-GEE) model with binomial distribution. Per test round in 2019-2021, 0.85-4.10 % of the Dutch dairy herds at risk became newly infected, with large regional differences. Several risk factors for becoming newly infected in the context of the low herd-level prevalence were identified. The most evident risk factors that were identified were having at least one infected or recently recovered dairy herd within 500 m (OR = 2.67), on-farm presence of pigs (OR = 1.63), introduction of more than 2 cattle from other herds in the previous 12 months (OR = 1.17), being in an area with a relative soil moisture of >0.54 % (OR = 1.31), being located in an area with a high water surface area (>2 %; OR = 1.14) and a larger herd size (OR = 1.65). These results indicate that, in addition to introduction of cattle, local transmission plays an important role in the between-herd transmission of Salmonella spp. Information on risk factors for becoming newly infected based on regularly collected data, can be used to improve surveillance and to implement targeted control measures against salmonellosis.

Prevalence and Characteristics of Salmonella from Tibetan Pigs in Tibet, China.

This study aimed to understand the epidemiological characteristics of Salmonella in Tibetan pigs. We isolated, identified, and examined via antimicrobial susceptibility testing on Salmonella from Tibetan pigs breeder farms and slaughterhouses in Tibet, China. A genetic evolutionary tree was constructed on the basis of whole genome sequencing (WGS). A total of 81 Salmonella isolates were isolated from 987 samples. The main serovars were Salmonella Typhimurium and Salmonella London in Tibetan pigs. The isolated Salmonella Typhimurium isolates subjected to antimicrobial susceptibility testing showed varying degrees of resistance to ß-lactams, aminoglycosides, fluoroquinolones, sulfonamides, tetracyclines, and amphenicols. WGS analysis was performed on 20 Salmonella Typhimurium isolates in Tibet (n = 10), Jiangsu (n = 10), and 205 genome sequences downloaded from the Enterobase database to reveal their epidemiological and genetic characteristics. They were divided into two clusters based on core genome single-nucleotide polymorphisms: Cluster A with 112 isolates from Tibet and other regions in China and Cluster B with 113 isolates from Jiangsu and other regions. The isolates in Cluster A were further divided into two subclusters: A-1 with 40 isolates including Tibet and A-2 with 72 isolates from other regions. Virulence factors analysis revealed that all isolates from Tibet carried adeG, but this observation was not as common in Salmonella isolates from Jiangsu and other regions of China. Antibiotic resistance genes (ARGs) analysis showed that all isolates from Tibet carried blaTEM-55 and rmtB, which were absent in Salmonella isolates from Jiangsu and other regions of China. Genetic characteristic analysis and biofilm determination indicated that the biofilm formation capabilities of the isolates from Tibet were stronger than those of the isolates from Jiangsu and other regions of China. Our research revealed the epidemic patterns and genomic characteristics of Salmonella in Tibetan pigs and provided theoretical guidance for the prevention and control of local salmonellosis.

Epidemiological and molecular investigations of Salmonella isolated from duck farms in southwest and around area of Shandong, China.

Salmonella is a zoonotic pathogen posing a serious risk to the farming industry and public health due to food animals serving as reservoirs for future contamination and spread of Salmonella. The present study is designed to monitor the contamination status of Salmonella in duck farms and the main control points during breeding. 160 strains of duck-derived Salmonella were isolated from the 736 samples (cloacal swabs, feces, water, feed, soil, air and dead duck embryos) collected in southwest Shandong Province and the province's surrounding area. The percentage of Salmonella-positive samples collected was 21.74 % (160/736), and the greatest prevalence from duck embryo samples (40.00 %, 36/90). These Salmonella were classified into 23 serotypes depending on their O and H antigens, in which S. Typhimurium (30.15 %), S. Kottbus (13.97 %) and S. Enteritidis (10.29 %) were the prevailing serotypes. Subsequently, the molecular subtyping was done. Clustered regularly interspaced short palindromic repeats (CRISPR) analysis showed that 41 strains of S. Typhimurium and 14 strains of S. Enteritidis were classified into 13 and 3 genotypes, respectively. 19 S. Kottbus isolates from different sources featured ST1546, ST198, ST321, and ST1690 by multilocus sequence typing (MLST) analysis, among which ST1546 belongs to S. Kottbus was a new ST. The minimum spanning tree analysis based on the two CRISPR loci and seven MLST loci from all S. Typhimurium, S. Enteritidis and S. Kottbus isolates revealed that duck embryos, feed and water were key control points to the spread of Salmonella along the breeding chain. Meanwhile, the emergence of S. Kottbus in duck flocks was considered a potential public health hazard.

Prebiotic galactooligosaccharide feed modifies the chicken gut microbiota to efficiently clear Salmonella.

Chicken meat is contaminated with Salmonella from the gut of infected chickens during slaughter. Eradication of Salmonella from broiler chickens through hygiene measures and/or vaccination is not cost-effective; complementary approaches are required. A mature gut microbiota obstructs Salmonella infection in chickens, and deliberate fortification of colonization resistance through prebiotic feed formulations would benefit public health and poultry production. Prebiotic galactooligosaccharides hastens Salmonella clearance from the gut of infected chickens. To better understand the role of galactooligosaccharides in colonization resistance, broiler chickens were raised on a wheat-soybean meal-based feed, with or without galactooligosaccharides for the first 24 days of life. Chickens were orally challenged with Salmonella enterica serovar Enteritidis at 20 days and the effect of supplementary galactooligosaccharides characterized by profiling Salmonella colonization, gut microbiota, innate immune response, and cecal short-chain fatty acid concentrations. Exposure to dietary galactooligosaccharides shortened the time to clear S. Enteritidis from the ceca. Differential abundance analysis of the cecal microbiota associated Salmonella challenge with a bacterial taxon belonging to the Acidaminococcaceae family (P < 0.005). Increased cecal concentrations of the short-chain fatty acids propionate and valerate were measured in Salmonella-challenged chickens sustained on either control or galactooligosaccharide-supplemented feed relative to mock-challenged controls; but far greater concentrations were detected in chickens fed a galactooligosaccharide-supplemented diet in early life. The abundance of the Acidaminococcaceae taxon exhibited a positive correlation with the cecal concentrations of propionate (ρ = 0.724, P = 0.008) and valerate (ρ = 0.71, P = 0.013). The absence of cecal pro-inflammatory transcriptional responses suggest that the rapid Salmonella clearance observed for the galactooligosaccharide-supplemented diet was not linked to innate immune function. IMPORTANCE: Work presented here identifies bacterial taxa responsible for colonization resistance to Salmonella in broiler chickens. Deliberate cultivation of these taxa with prebiotic galactooligosaccharide has potential as a straight-forward, safe, and cost-effective intervention against Salmonella. We hypothesize that catabolism of galactooligosaccharide and its breakdown products by indigenous microorganisms colonizing the chicken gut produce excess levels of propionate. In the absence of gross inflammation, propionate is inimical to Salmonella and hastens intestinal clearance.

Co-exposure to polyethylene fiber and Salmonella enterica serovar Typhimurium alters microbiome and metabolome of in vitro chicken cecal mesocosms.

Humans and animals encounter a summation of exposures during their lifetime (the exposome). In recent years, the scope of the exposome has begun to include microplastics. Microplastics (MPs) have increasingly been found in locations, including in animal gastrointestinal tracts, where there could be an interaction with Salmonella enterica serovar Typhimurium, one of the commonly isolated serovars from processed chicken. However, there is limited knowledge on how gut microbiomes are affected by microplastics and if an effect would be exacerbated by the presence of a pathogen. In this study, we aimed to determine if acute exposure to microplastics in vitro altered the gut microbiome membership and activity. The microbiota response to a 24 h co-exposure to Salmonella enterica serovar Typhimurium and/or low-density polyethylene (PE) microplastics in an in vitro broiler cecal model was determined using 16S rRNA amplicon sequencing (Illumina) and untargeted metabolomics. Community sequencing results indicated that PE fiber with and without S. Typhimurium yielded a lower Firmicutes/Bacteroides ratio compared with other treatment groups, which is associated with poor gut health, and overall had greater changes to the cecal microbial community composition. However, changes in the total metabolome were primarily driven by the presence of S. Typhimurium. Additionally, the co-exposure to PE fiber and S. Typhimurium caused greater cecal microbial community and metabolome changes than either exposure alone. Our results indicate that polymer shape is an important factor in effects resulting from exposure. It also demonstrates that microplastic-pathogen interactions cause metabolic alterations to the chicken cecal microbiome in an in vitro chicken cecal mesocosm. IMPORTANCE: Researching the exposome, a summation of exposure to one's lifespan, will aid in determining the environmental factors that contribute to disease states. There is an emerging concern that microplastic-pathogen interactions in the gastrointestinal tract of broiler chickens may lead to an increase in Salmonella infection across flocks and eventually increased incidence of human salmonellosis cases. In this research article, we elucidated the effects of acute co-exposure to polyethylene microplastics and Salmonella enterica serovar Typhimurium on the ceca microbial community in vitro. Salmonella presence caused strong shifts in the cecal metabolome but not the microbiome. The inverse was true for polyethylene fiber. Polyethylene powder had almost no effect. The co-exposure had worse effects than either alone. This demonstrates that exposure effects to the gut microbial community are contaminant-specific. When combined, the interactions between exposures exacerbate changes to the gut environment, necessitating future experiments studying low-dose chronic exposure effects with in vivo model systems.

Virulence factors of Salmonella spp. isolated from free-living grass snakes Natrix natrix.

Salmonellosis associated with reptiles is a well-researched topic, particularly in China and the United States, but it occurs less frequently in Europe. The growth of the human population and changes in the environment could potentially increase the interaction between humans and free-living reptiles, which are an unidentified source of Salmonella species. In this study, we sought to explore this issue by comparing the microbiota of free-living European grass snakes, scientifically known as Natrix natrix, with that of captive banded water snakes, or Nerodia fasciata. We were able to isolate 27 strains of Salmonella species from cloacal swabs of 59 N. natrix and 3 strains from 10 N. fasciata. Our findings revealed that free-living snakes can carry strains of Salmonella species that are resistant to normal human serum (NHS). In contrast, all the Salmonella species strains isolated from N. fasciata were sensitive to the action of the NHS, further supporting our findings. We identified two serovars from N. natrix: Salmonella enterica subspecies diarizonae and S. enterica subspecies houtenae. Additionally, we identified three different virulotypes (VT) with invA, sipB, prgH, orgA, tolC, iroN, sitC, sifA, sopB, spiA, cdtB and msgA genes, and ß-galactosidase synthesised by 23 serovars. The identification of Salmonella species in terms of their VT is a relatively unknown aspect of their pathology. This can be specific to the serovar and pathovar and could be a result of adaptation to a new host or environment.

Retrospective study on the occurrence of Salmonella serotypes in veterinary specimens of Atlantic Canada (2012-2021).

AIM: This study aimed to summarize the frequency and the antimicrobial susceptibility profiles of the Salmonella serotypes identified from the specimens of companion animals, livestock, avian, wildlife and exotic species within Atlantic Canada. MATERIALS AND METHODS: The retrospective electronic laboratory data of microbiological analyses of a selected subset of samples from 03 January 2012 to 29 December 2021 submitted from various animal species were retrieved. The frequency of Salmonella serotypes identified, and their antimicrobial susceptibility results obtained using the disk diffusion or broth method were analysed. The test results were interpreted according to the Clinical and Laboratory Standards Institute standard. The Salmonella serotypes were identified by slide agglutination (Kauffman-White-Le-Minor Scheme) and/or the Whole Genome Sequencing for the Salmonella in silico Serovar Typing Resource-based identification. RESULTS: Of the cases included in this study, 4.6% (n = 154) had at least one Salmonella isolate, corresponding to 55 different serovars. Salmonella isolation was highest from exotic animal species (n = 40, 1.20%), followed by porcine (n = 26, 0.78%), and canine (n = 23, 0.69%). Salmonella subsp. enterica serovar Typhimurium was predominant among exotic mammals, porcine and caprine samples, whereas S. Enteritidis was mostly identified in bovine and canine samples. S. Typhimurium of porcine origin was frequently resistant (>70.0%) to ampicillin. In contrast, S. Typhimurium isolates from porcine and caprine samples were susceptible (>70.0%) to florfenicol. S. Oranienburg from equine samples was susceptible to chloramphenicol, but frequently resistant (>90.0%) to azithromycin. In avian samples, S. Copenhagen was susceptible (>90.0%) to florfenicol, whereas Muenchen was frequently resistant (>90.0%) to florfenicol. S. subsp. diarizonae serovar IIIb:61:k:1,5 of ovine origin was resistant (50.0% isolates) to sulfadimethoxine. No significant changes were observed in the antibiotic resistance profiles across the study years. CONCLUSIONS: This report provides data for surveillance studies, distribution of Salmonella serotypes and their antimicrobial resistance among veterinary specimens of Atlantic Canada.

Competitive exclusion products as an antimicrobial alternative to control Salmonella Heidelberg in broilers.

Intestinal infections caused by non-typhoidal Salmonella spp., along with antimicrobial resistance spread are a major food safety concern worldwide. Here, we evaluate the potential of competitive exclusion products developed by anaerobic or aerobic conditions to control systemic infection, cecal colonization, fecal excretion, and improve the intestinal health in broilers challenged by Salmonella Heidelberg (SH). A total of 105 day-old chickens were randomly distributed into three experimental groups: A (untreated control), B (treated with anaerobic culture), and C (treated with aerobic culture). During 21 days, morphometric parameters of the small intestine were analyzed using microscopy, fecal excretions by cloacal swabs, systemic infection, and cecal colonization by colony-forming unit counts (CFU/g). The results indicated the lowest number of positive swabs (45.33%) recovered from Group C, followed by Group B (71.8%) and Group A (85.33%). The bacterial enumeration revealed the lowest amounts in Group C at the necropsy realized in 5-, 7-, and 14-days post-infection (DPI) (P = 0.0010, P = 0.0048, and P = 0.0094, respectively). Statistical differences between intestinal morphometrics were observed in the Group C at 21 DPI. Our results suggest that the product developed under aerobic conditions can improve intestinal health, protecting birds against SH.

Development of a 1-step multiplex PCR assay for the detection of S. Enteritidis, S. Pullorum, S. Typhimurium, and S. Infantis associated with poultry production.

Salmonellosis in poultry is detrimental to the advancement of the breeding industry and poses hazards to human health. Approximately 2,600 Salmonella varieties exist, among which S. Enteritidis, S. Pullorum, S. Typhimurium, and S. Infantis are prevalent serotypes in the poultry industry in recent years. They can also infect humans by contaminating poultry eggs and meat. Therefore, identifying these serotypes is crucial for successful preventive and control interventions. The White-Kauffmann-Le Minor scheme is time-consuming and requires expensive reagents. Whole-genome sequencing (WGS) and other molecular biology techniques require skilled technical staff. In comparison, the polymerase chain reaction (PCR) is more accurate, rapid, and inexpensive, thus proving suitable for widespread application in the poultry industry. Here, we selected 4 specific primers: lygD, mdh, ipaJ, and SIN_02055, which correspond to detecting S. Enteritidis, S. Typhimurium, S. Pullorum, and S. Infantis, respectively. They were integrated into a 1-step multiplex PCR method. We optimized the PCR method by utilizing specificity test results to determine the optimal annealing temperature (57°C). The PCR method exhibited excellent sensitivity for genomic DNA and bacterial cultures. We used the developed method to determine 157 clinical Salmonella isolates from various stages of the poultry production chain. The results aligned with serotype data generated via WGS analysis, demonstrating the method's excellent accuracy. In conclusion, this study developed a 1-step multiplex PCR method that simultaneously identifies S. Enteritidis, S. Typhimurium, S. Pullorum, and S. Infantis, allowing routine mass detection in the grass-root poultry industry.