Global Prevalence of Yersinia enterocolitica in Cases of Gastroenteritis: A Systematic Review and Meta-Analysis

Pathogenicity and virulence of Yersinia

The genus Yersinia includes human, animal, insect, and plant pathogens as well as many symbionts and harmless bacteria. Within this genus are Yersinia enterocolitica and the Yersinia pseudotuberculosis complex, with four human pathogenic species that are highly related at the genomic level including the causative agent of plague, Yersinia pestis. Extensive laboratory, field work, and clinical research have been conducted to understand the underlying pathogenesis and zoonotic transmission of these pathogens. There are presently more than 500 whole genome sequences from which an evolutionary footprint can be developed that details shared and unique virulence properties. Whereas the virulence of Y. pestis now seems in apparent homoeostasis within its flea transmission cycle, substantial evolutionary changes that affect transmission and disease severity continue to ndergo apparent selective pressure within the other Yersiniae that cause intestinal diseases. In this review, we will summarize the present understanding of the virulence and pathogenesis of Yersinia, highlighting shared mechanisms of virulence and the differences that determine the infection niche and disease severity.

Research progress on the detection of foodborne pathogens based on aptamer recognition

Foodborne diseases caused by bacterial contamination are a serious threat to food safety and human health. The classical plate culture method has the problems of long detection cycle, low sensitivity and specificity, and complicated operation, which cannot meet the growing demand for rapid quantitative detection of pathogenic bacteria. The frequent outbreak of foodborne diseases has put forward higher requirements for rapid and simple detection technology of foodborne pathogens. Aptamer is a kind of oligonucleotide fragment that can recognize targets with the advantages of high affinity and good specificity. The target can be range from proteins, small molecules, cells bacteria, and even viruses. Herein, the latest advances in sensitive and rapid detection of foodborne pathogens based on aptamer recognition was reviewed. Special attention has been paid to the obtained sequences of aptamers to various foodborne pathogens, the optimization of sequences, and the mechanism of aptamer recognition. Then, the research progress of biosensors for the detection of pathogenic bacteria based on aptamer recognition were summarized. Some challenges and prospects for the detection of foodborne pathogens based on aptamer recognition were prospected. In summary, with the further deepening of aptamer research and improvement of detection technology, aptamer-based recognition can meet the needs of rapid, sensitive, and accurate detection in practical applications.

Stringent Response Factor DksA Contributes to Fatty Acid Degradation Function to Influence Cell Membrane Stability and Polymyxin B Resistance of Yersinia enterocolitica

DksA is a proteobacterial regulator that binds directly to the secondary channel of RNA polymerase with (p)ppGpp and is responsible for various bacterial physiological activities. While (p)ppGpp is known to be involved in the regulation and response of fatty acid metabolism pathways in many foodborne pathogens, the role of DksA in this process has yet to be clarified. This study aimed to characterize the function of DksA on fatty acid metabolism and cell membrane structure in Yersinia enterocolitica. Therefore, comparison analysis of gene expression, growth conditions, and membrane permeabilization among the wide-type (WT), DksA-deficient mutant (YEND), and the complemented strain was carried out. It confirmed that deletion of DksA led to a more than four-fold decrease in the expression of fatty acid degradation genes, including fadADEIJ. Additionally, YEND exhibited a smaller growth gap compared to the WT strain at low temperatures, indicating that DksA is not required for the growth of Y. enterocolitica in cold environments. Given that polymyxin B is a cationic antimicrobial peptide that targets the cell membrane, the roles of DksA under polymyxin B exposure were also characterized. It was found that DksA positively regulates the integrity of the inner and outer membranes of Y. enterocolitica under polymyxin B, preventing the leakage of intracellular nucleic acids and proteins and ultimately reducing the sensitivity of Y. enterocolitica to polymyxin B. Taken together, this study provides insights into the functions of DksA and paves the way for novel fungicide development.

Endoscopic and video capsule endoscopic observation of Yersinia enterocolitis

A woman in her late 20s suffered from epigastralgia following lower abdominal pain with diarrhea. Kampo medicine relieved the complaints, but the pain recurred a month later. She had immigrated from Vietnam to Japan 6 months before the onset of the abdominal pain. Blood test findings were almost within normal limits, except for mild C-reactive protein elevation and positive Helicobacter pylori antibody findings. Colonoscopy revealed an edematous cobblestone-like appearance at the end of the ileum with irregular ulceration mimicking Crohn's disease. Video capsule endoscopy was performed to detect lesions in the small intestine and demonstrated irregular ileal ulcer, reminiscent of Crohn's disease. A biopsy performed during colonoscopy demonstrated granulomatous inflammation with a moderate accumulation of plasma cells and mononuclear cells. The bacterial culture of the biopsy specimen proved the growth of Yersinia enterocolitica. Levofloxacin 500 mg for 7 days rapidly relieved abdominal pain. Yersinia enterocolitis is rare in developed countries, but as a differential diagnosis for Crohn's disease, it is important to treat. This is the first case report of the video capsule endoscopy findings of Yersinia enterocolitis. Video capsule endoscopy can help to confirm the spread of the lesions of Yersinia enterocolitis.

Yersinia enterocolitica in Crohn’s disease

Increasing attention is being paid to the unique roles gut microbes play in both physiological and pathological processes. Crohn’s disease (CD) is a chronic, relapsing, inflammatory disease of the gastrointestinal tract with unknown etiology. Currently, gastrointestinal infection has been proposed as one initiating factor of CD. Yersinia enterocolitica, a zoonotic pathogen that exists widely in nature, is one of the most common bacteria causing acute infectious gastroenteritis, which displays clinical manifestations similar to CD. However, the specific role of Y. enterocolitica in CD is controversial. In this Review, we discuss the current knowledge on how Y. enterocolitica and derived microbial compounds may link to the pathogenesis of CD. We highlight examples of Y. enterocolitica-targeted interventions in the diagnosis and treatment of CD, and provide perspectives for future basic and translational investigations on this topic.

Retrospective study on the prevalence of Yersinia enterocolitica in food collected in Umbria region (central Italy)

Yersinia enterocolitica represents one of the main foodborne pathogens in Europe and the evaluation of possible sources of contamination and its prevalence in food is of considerable interest for risk analysis approach. The results of the search for Yersinia enterocolitica in food samples taken in Umbria region (central Italy) were evaluated during the years 2015-2018. Different types of foods were considered, both ready-to-eat (meat products, dairy products, and raw vegetables) and meat preparations to be eaten after cooking. Samples were assayed by molecular screening for the species indicator gene ompF. Screening positives were subjected to isolation and characterization by searching for specific virulence marker genes, including the ail gene responsible for invasiveness and the ystB gene for the production of enterotoxin. The total prevalence of positive samples for Yersinia enterocolitica was 16.86% with a higher percentage of positive samples in meat preparations (19.35%), followed by ready-to-eat vegetables (11.76%). Poultry meat samples had a higher prevalence than pork and beef samples. Neither positive samples were found in meat products and dairy, nor seasonality in positivity was observed. All isolated strains of Yersinia enterocolitica were biotype 1A, with absence of the ail virulence gene but presence of ystB gene. Since the strains isolated from human patients appear to be primarily biotypes that possess the ail marker, future investigations would be needed regarding the real role of biotype 1A in human disease. In this context, attention should certainly be paid to ready-to-eat vegetables and to careful cooking of meat preparations.

Prevalence and Persistence of Multidrug-Resistant Yersinia enterocolitica 4/O:3 in Tonsils of Slaughter Pigs from Different Housing Systems in Croatia

Yersinia enterocolitica is one of the priority biological hazards in pork inspection. Persistence of the pathogen, including strains resistant to antimicrobials, should be evaluated in pigs from different housing systems for risk ranking of farms. In this 2019 study, tonsils were collected from 234 pigs, of which 69 (29.5%) were fattened on 3 big integrated farms, 130 (55.5%) on 10 medium-sized farms, and 35 (15%) on 13 small family farms. In addition, 92 pork cuts and minced meat samples from the same farms were tested for the presence of Y. enterocolitica using the culture method. Phenotypic and genetic characteristics of the isolates were compared with previously collected isolates from 2014. The overall prevalence of Y. enterocolitica in pig tonsils was 43% [95% CI 36.7−49.7]. In pigs from big integrated, medium-sized, and small family farms, the prevalence was 29%, 52%, and 40%, respectively. All retail samples of portioned and minced pork tested negative for pathogenic Y. enterocolitica, likely due to high hygienic standards in slaughterhouses/cutting meat or low sensitivity of culture methods in these matrices. The highest recovery rate of the pathogen from tonsils was found when alkali-treated PSB and CIN agar were combined. The biosecurity category of integrated and medium farms did not affect the differences in prevalence of Y. enterocolitica (p > 0.05), in contrast to family farms. Pathogenic ail-positive Y. enterocolitica biotype 4 serotype O:3 persisted in the tonsils of pigs regardless of the type of farm, slaughterhouse, and year of isolation 2014 and 2019. PFGE typing revealed the high genetic concordance (80.6 to 100%) of all the Y. enterocolitica 4/O:3 isolates. A statistically significant higher prevalence of multidrug-resistant Y. enterocolitica 4/O:3 isolates was detected in the tonsils of pigs from big integrated farms compared to the other farm types (p < 0.05), with predominant and increasing resistance to nalidixic acid, chloramphenicol, and streptomycin. This study demonstrated multidrug resistance of the pathogen in pigs likely due to more antimicrobial pressure on big farms, with intriguing resistance to some clinically relevant antimicrobials used in the treatment of yersiniosis in humans.