Yersinia enterocolitica infections impose a significant public health and socioeconomic burden on human population in many countries. The current study investigated the prevalence, antimicrobial resistance profile and molecular diversity of Y. enterocolitica in meat and meat products across various retail outlets in selected provinces of South Africa (SA). In a cross-sectional study, a total of 581 retail meat and meat products were collected from four cities across three provinces of SA. Samples were from beef and pork products, which included 292 raw intact, 167 raw processed, and 122 ready-to-eat (RTE) meats. Samples were analysed using classical microbiological methods for isolation, identification and biotyping of Y. enterocolitica. Conventional polymerase chain reaction (PCR) was performed for confirmation, serotyping, screening of virulence (n = 11) and antimicrobial resistance (n = 18) genes. Phenotypic antimicrobial resistance profiles were determined against 12 antibiotics discs, using disc diffusion method. The overall prevalence of 12% (70/581) was reported across all cities with contamination proportion reported in samples collected from raw intact 15% (43/292), followed by raw processed 11% (18/167) and RTE meats 7% (9/122). All positive isolates were of biotype 1A with 7% (5/70) belonging to bioserotype 1A/O:8. Most of the isolates harboured ymoA, ystB, fepD, ail, fepA, invA and myfA virulence genes. High antimicrobial resistance frequency was observed for ampicillin (94%), cephalothin (83%) and amoxicillin (41%), respectively. Of the 18 tested antimicrobial resistance genes, blaTEM was the most predominant (40%) followed by cmlA (21%). This study reveals the presence of antimicrobial resistant Y. enterocolitica possessing virulent genes of public health importance in products of animal origin, therefore, health monitoring and surveillance of this pathogen is required.

Yersiniosis is a zoonosis causing gastroenteritis, diarrhoea, and occasionally reactive arthritis and septicaemia. Cases are often linked to meat consumption and the most common aetiological agent is the Gram-negative bacilliform Yersinia enterocolitica bacterium. The occurrence of Yersinia spp. among wild animals has mostly been studied in wild boar, but it has seldom been in other species.

Yersinia species, especially Yersinia enterocolitica, are considered as the most prevalent milk-borne pathogens. Y. enterocolitica is the causative agent of yersiniosis, a zoonotic disease of growing epidemiological importance with significant consequences for public health. A total of 300 samples out of milk and milk products water and environmental samples were collected from dairy cattle rural house and local dairy shops and vendors to be investigated for presence of Yersinia spp. Isolates were molecularly identified and screened for virulence markers, biofilm production and antimicrobial resistance profile. Finally, the antimicrobial activity of milk proteins hydrolysates against Y. enterocolitica was detected. Yersinia spp. was recovered from 50% of the examined samples. The most prevalent species was Y. enterocolitica (isolated from 21.7 and 30% of milk and its products, and environmental samples, respectively). Detection of virulence genes revealed that 24% of Y. enterocolitica isolates harbored both ail and yst genes. Y. enterocolitica isolates showed high antimicrobial resistance to various antimicrobials. Also, different biofilm phenotypes were produced by these isolates. The most produced biofilm phenotype was moderate (68.9%). The parent proteins (CCP, CWP) and their pepsin hydrolysates (P-CCP and P-CWP) were potentially effective in inhibiting Y. enterocolitica growth and peptides P-CWP exhibited the strongest effect against Y. enterocolitica.

Considerable difficulties are associated with the isolation of Yersinia enterocolitica from food particularly milk and milk products. Most methods are time consuming require enrichment steps and are unable to differentiate pathogenic isolates from non pathogenic ones. The purpose of this study was to evaluate the detection of Yersinia enterocolitica in milk by both polymerase chain reaction (PCR) and conventional culturing methods. Fifty milk samples were collected from Shami goats in North Sinai governorate. Two primers (DG26 and DG63) were used in PCR and the size of the PCR-product was 440bp. The results obtained by PCR technique were in good agreement with that obtained by conventional culturing method. Five samples (10%) were positive by PCR while 4 samples were positive by conventional culturing method. Interestingly, PCR results are obtained within few hours. Moreover, it solved the problem of interpretation of classical biochemical and serological typing in one step without necessity of using additional examinations. This makes diagnosis in food control laboratories much faster and more efficient.

Yersiniosis is a zoonosis causing gastroenteritis, diarrhoea, and occasionally reactive arthritis and septicaemia. Cases are often linked to meat consumption and the most common aetiological agent is the Gram-negative bacilliform Yersinia enterocolitica bacterium. The occurrence of Yersinia spp. among wild animals has mostly been studied in wild boar, but it has seldom been in other species. A total of 1,868 faecal samples from animals found dead or hunted were collected between 2015 and 2018 in the Valle d’Aosta region of the northwestern Italian Alps. Alpine ibex faecal samples were collected during a health monitoring program in 2018. Bacteria were isolated via PCR and confirmed as Y. enterocolitica biochemically. Strain antimicrobial susceptibility was tested by Kirby–Bauer disc diffusion, and the presence of virulence factors and antimicrobial resistance genes was investigated using whole-genome sequencing. Yersinia enterocolitica strains of biotype 1A were detected in six faecal samples from red deer (0.93%), roe deer (0.49%) and red foxes (0.7%). Strains found in beech martens (3.57%) and Alpine ibex (2.77%) belonged to biotypes 1B and 5, respectively and harboured the pYPTS01 plasmid that had only been detected in Y. pseudotuberculosis PB1/+. All the isolates were resistant to ampicillin and erythromycin. The biovar 1A strains exhibited different virulence factors and behaved like non-pathogenic commensals. The strain from an Alpine ibex also harboured the self-transmissible pYE854 plasmid that can mobilise itself and the pYPTS01 plasmid to other strains. The beech marten could be considered a sentinel animal for Y. enterocolitica. Phenotypic resistance may account for the ability of all the strains to resist β-lactams.

Objective-To assess antimicrobial resistance and transfer of virulence genes facilitated by subtherapeutic concentrations of antimicrobials in swine intestines. Animals-20 anesthetized pigs experimentally inoculated with donor and recipient bacteria. Procedures-4 recipient pathogenic bacteria (Salmonella enterica serotype Typhimurium, Yersinia enterocolitica, Shigella flexneri, or Proteus mirabilis) were incubated with donor bacteria in the presence of subinhibitory concentrations of 1 of 16 antimicrobials in isolated ligated intestinal loops in swine. Donor Escherichia coli contained transferrable antimicrobial resistance or virulence genes. After coincubations, intestinal contents were removed and assessed for pathogens that acquired new antimicrobial resistance or virulence genes following exposure to the subtherapeutic concentrations of antimicrobials. Results-3 antimicrobials (apramycin, lincomycin, and neomycin) enhanced transfer of an antimicrobial resistance plasmid from commensal E coli organisms to Yersinia and Proteus organisms, whereas 7 antimicrobials (florfenicol, hygromycin, penicillin G, roxarsone, sulfamethazine, tetracycline, and tylosin) exacerbated transfer of an integron (Salmonella genomic island 1) from Salmonella organisms to Yersinia organisms. Sulfamethazine induced the transfer of Salmonella pathogenicity island 1 from pathogenic to nonpathogenic Salmonella organisms. Six antimicrobials (bacitracin, carbadox, erythromycin, sulfathiazole, tiamulin, and virginiamycin) did not mediate any transfer events. Sulfamethazine was the only antimicrobial implicated in 2 types of transfer events. Conclusions and Clinical Relevance-10 of 16 antimicrobials at subinhibitory or subtherapeutic concentrations augmented specific antimicrobial resistance or transfer of virulence genes into pathogenic bacteria in isolated intestinal loops in swine. Use of subtherapeutic antimicrobials in animal feed may be associated with unwanted collateral effects.

Yersinia enterocolitica is an enteropathogen that widely distributed in nature with high public health relevance and transmitted mostly by contaminated food. This study aimed to study the prevalence; phenotypic and genotypic characterization of the isolated Y. enterocolitica strains from 175 random samples of cow milk; beef; chicken meat; diarrheic cow and sheep faeces(35 for each), collected from different shops; dairy herds and sheep flocks, at Kaliobia Governorate Egypt, beside, investigation of the possible relationships among the isolated Y. enterocolitica  strains. The obtained results revealed that 18 Y. enterocolitica isolates were recovered; they were isolated from cow milk samples (6/17.1%); chicken meat (5/14.3%); beef (4/11.4%) and cow faeces (3/8.6%), but failed to be isolated from sheep faeces. Four biotype groups (four 1A; seven 1B, three biotype 3 and four biotype4) were recognized biochemically. Moreover, many phenotypic virulence factors detected in some isolates as  hemlysin , lecithinase, lipase ,proteinase and biofilm formation   the isolated Y. enterocolitica were highly resistant for Penicillin G. ; ampicillin ; tetracycline ; amoxicillin and streptomycin ,but   they were highly sensitive to meropenem ; norfloxacin ; ciprofloxacin ; gentamycin and Florfenicol. PCR appeared that, the ail gene was amplified in five and yst gene in four out of eight studied Y. enterocolitica strains. ERIC PCR showed many bands from 214 to 1228 and divided the 8 isolate to three genotypes. In conclusion, Y. enterocolitica strains with multiple antimicrobial resistances were isolated from milk, beef, chicken meat, cow faeces and could represent a public health concern. So, strict hygienic measures should be applied to minimize Y. enterocolitica contamination in milk and meat, also the antimicrobial resistances of Y. enterocolitica isolates should be monitored continuously to avoid public health hazards.