Prevalence, characterization and antimicrobial susceptibility of Yersinia enterocolitica and other Yersinia species found in fruits and vegetables from the European Union

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.

Comparison of inactivation kinetics of Yersinia enterocolitica in vegan and non-vegan kimchi during fermentation

Yersinia enterocolitica is occasionally detected in kimchi, a traditional food prepared from fermented vegetables. Changes in growth properties of Y. enterocolitica during kimchi fermentation are largely unknown. We investigated the viability of Y. enterocolitica during the fermentation of vegan and non-vegan kimchi at different temperatures. Changes in Y. enterocolitica population, pH, and titratable acidity were measured for 24 days. In a suspension test with kimchi juice, populations of three Y. enterocolitica strains were above 3.30 log₁₀ CFU/mL at pH > 5 for 7 days. Yersinia enterocolitica counts in vegan kimchi were considerably reduced at 0 °C and 6 °C. During fermentation at 6 °C, Y. enterocolitica populations in non-vegan kimchi and vegan kimchi were not detected starting from days 14 and 10, respectively. In kimchi samples stored at 0 °C and 6 °C, Y. enterocolitica survival correlated with pH changes during fermentation; in samples stored for up to 24 days, Y. enterocolitica was not detected. According to the k _max values from the "log-linear with shoulder and tail" model, Y. enterocolitica was more sensitive to vegan kimchi fermentation than to non-vegan kimchi fermentation. Our findings provide an important basis for ensuring the safe production of kimchi without Y. enterocolitica contamination. Further research is necessary to elucidate the mechanism of Y. enterocolitica inactivation and the major bacterial and physicochemical factors involved in kimchi fermentation.

Higher Resistance of Yersinia enterocolitica in Comparison to Yersinia pseudotuberculosis to Antibiotics and Cinnamon, Oregano and Thyme Essential Oils

Yersiniosis is an important zoonotic disease; however, data are scarce on the resistance of enteropathogenic yersiniae, especially that of Y. pseudotuberculosis. Minimum inhibitory concentrations (MIC) of 21 antibiotics and 3 essential oils (EOs) were determined by broth microdilution for Y. enterocolitica bioserotype 4/O:3 strains isolated from domestic swine (n = 132) and Y. pseudotuberculosis strains isolated from wild boars (n = 46). For 15 of 21 antibiotics, statistically significant differences were found between MIC values of Y. enterocolitica and Y. pseudotuberculosis. While Y. enterocolitica was more resistant to amoxiclav, ampicillin, cefotaxime, cefuroxime, gentamicin, imipenem, meropenem, tetracycline, tobramycin, and trimethoprim, Y. pseudotuberculosis was more resistant to cefepime, ceftazidime, colistin, erythromycin, and nitrofurantoin. Statistically significant differences were found between various essential oils (p < 0.001) and species (p < 0.001). The lowest MICs for multiresistant Y. enterocolitica (n = 12) and Y. pseudotuberculosis (n = 12) were obtained for cinnamon (median 414 and 207 μg/mL, respectively) and oregano EOs (median 379 and 284 μg/mL), whereas thyme EO showed significantly higher MIC values (median 738 and 553 μg/mL; p < 0.001). There was no difference between Y. enterocolitica strains of plant (1A) and animal (4/O:3) origin (p = 0.855). The results show that Y. enterocolitica is generally more resistant to antimicrobials than Y. pseudotuberculosis.

Detection, characterization, and antimicrobial susceptibility of Yersinia enterocolitica in different types of wastewater in the Czech Republic

AIMS

The purpose of the study was to evaluate the occurrence of Yersinia enterocolitica in different types of wastewater and to characterize the isolates by biotyping, serotyping, and antimicrobial susceptibility testing. In addition, cultivation protocols were evaluated.

METHODS AND RESULTS

The occurrence of Y. enterocolitica was determined in treated and untreated municipal wastewater, as well as in hospital, slaughterhouse, and cowshed wastewater. Y. enterocolitica was detected in 84.1% of the wastewater samples, while the main sources were untreated municipal and slaughterhouse wastewater. In contrast, the lowest incidence was found in hospital wastewater. An exclusive occurrence of biotype 1A (98.3%) was detected. Pathogenic bio-serotypes 4/O:3 and 3/O:3 were isolated only from slaughterhouse wastewater. The highest resistance rates were observed for ampicillin (92.5%) and amoxicillin-clavulanic acid (36.8%).

CONCLUSIONS

Y. enterocolitica was commonly detected in wastewater, although the prevalence varied depending on the origin of the wastewater. No single cultivation protocol was able to recover Y. enterocolitica isolates from such a complex matrix as wastewater.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study provided data that can contribute to the evaluation of wastewater as a source of Y. enterocolitica and to understanding the threat of wastewater isolates to human health.

Whole-genome sequencing-based prediction and analysis of antimicrobial resistance in Yersinia enterocolitica from Ningxia, China

Focusing on resistance trends and transmission patterns of pathogenic microorganisms is a major priority for national surveillance programs. The use of whole-genome sequencing for antimicrobial susceptibility testing (WGS-AST) is a powerful alternative to traditional microbiology laboratory methods. Yersinia enterocolitica antimicrobial resistance (AMR) in the Ningxia Hui Autonomous Region has yet to be described thoroughly in current studies. We assessed and monitored the development of Y. enterocolitica AMR in the Ningxia Hui Autonomous Region during 2007–2019 based on WGS-AST. Resistance genotypes were predicted based on WGS. Antimicrobial resistance testing using classical microbiology determined resistance to 13 antimicrobial agents in 189 Y. enterocolitica isolates from Ningxia. The highest resistance level was 97.88% for cefazolin, followed by ampicillin (AMP) (44.97%), ciprofloxacin (CIP) (25.40%), streptomycin (STR) (11.11%), and tetracycline (TET) (10.58%). Isolates emerged as chloramphenicol (CHL) and trimethoprim/sulfamethoxazole (SXT) resistant. The primary plasmid types were IncFII(Y) and ColRNAI. The TET, STR, and SXT resistance were mediated by the tetA, aph(6)-Id, aph(3″)-Ib, and sul2 genes located on the IncQ1 plasmid. The resistant strains were predominantly biotype 4/O:3/ST429 and the hosts were pigs and patients. The number of multidrug-resistant (MDR) strains was of concern, at 27.51%. At present, the prediction of antimicrobial resistance based on WGS requires a combination of phenotypes. From 2007 to 2019, Y. enterocolitica isolates from the Ningxia Hui Autonomous Region showed a relatively high rate of resistance to cefazolin (CZO) and some resistance to AMP, CIP, STR, and TET. CIP, SXT, and TET showed a relatively clear trend of increasing resistance. Plasmids carrying multiple drug resistance genes are an important mechanism for the spread of antimicrobial resistance. Isolates with low pathogenicity were more likely to present an AMR phenotype than non-pathogenic isolates.

Isolation and characterization of Yersinia enterocolitica from foods in Apulia and Basilicata regions (Italy) by conventional and modern methods

Yersiniosis is the third most reported food-borne zoonosis in Europe. The aim of the present study was to perform the search for Yersinia enterocolitica in food samples collected from Apulia and Basilicata regions (Southern Italy) and to characterize any isolates by classical and modern analytical methods. A total of 130 samples were analyzed between July 2018 and July 2019: most of them were raw milk and dairy products made from it. Furthermore, 8 out of 130 samples were individual milk samples collected from bovines reared in a Brucella-free farm which showed false positive serological reaction for brucellosis due to the presence of pathogenic Y. enterocolitica O:9 biotype 2 in faeces. The Real Time PCR targeting the ail gene and the culture method were performed to detect pathogenic Y. enterocolitica. Isolates were subjected to API 20E (Biomerieux) and MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization Time-of-Flight) for species identification. All samples were negative for the ail gene. The culture method allowed to isolate suspicious colonies from 28 samples. The API 20E system and the MALDI-TOF MS technique identified 20 Y. enterocolitica and 1 Y. intermedia in a concordant way. The remaining 7 strains were all identified as Y. enterocolitica by the API 20E system, while the MALDI-TOF MS recognized 4 Y. intermedia, 1 Y. bercovieri and 2 Y. massiliensis. Genotypic characterization of the discordant strains was performed by rMLST and it confirmed the MALDI-TOF MS’ results. Only non-pathogenic Y. enterocolitica biotype 1A strains were found, although with a non-negligible prevalence (P = 0.15 with CI _95% = ± 0.06). This study indicates a poor circulation of pathogenic Y. enterocolitica in food products made and marketed in the investigated areas. However, the small number of samples, insufficient for some food categories such as meat and vegetable, does not allow to exclude the presence of pathogenic strains at all.

African nightshades (Solanum nigrum complex): The potential contribution to human nutrition and livelihoods in sub-Saharan Africa

Achieving zero hunger in sub-Saharan Africa (SSA) without minimizing postharvest losses of agricultural products is impossible. Therefore, a holistic approach is vital to end hunger, simultaneously improving food security, diversity, and livelihoods. This review focuses on the African nightshades (ANS) Solanum spp. contribution to improving food and nutrition security in SSA. Different parts of ANS are utilized as food and medicine; however, pests and diseases hinder ANS utilization. African nightshade is rich in micronutrients such as β-carotene, vitamins C and E, minerals (iron, calcium, and zinc), and dietary fiber. The leaves contain a high amount of nutrients than the berries. Proper utilization of ANS can contribute to ending hidden hunger, mainly in children and pregnant women. Literature shows that ANS contains antinutritional factors such as oxalate, phytate, nitrate, and alkaloids; however, their quantities are low to cause potential health effects. Several improved varieties with high yields, rich in nutrients, and low alkaloids have been developed in SSA. Various processing and preservation techniques such as cooking, drying, and fermentation are feasible techniques for value addition on ANS in SSA; moreover, most societies are yet to adopt them effectively. Furthermore, promoting value addition and commercialization of ANS is of importance and can create more jobs. Therefore, this review provides an overview of ANS production and challenges that hinder their utilization, possible solutions, and future research suggestions. This review concludes that ANS is an essential nutritious leafy vegetable for improving nutrition and livelihoods in SSA.

Molecular evaluation of quorum quenching potential of vanillic acid against Yersinia enterocolitica through transcriptomic and in silico analysis

Introduction. Yersinia enterocolitica is one of the leading food-borne entero-pathogens causing various illnesses ranging from gastroenteritis to systemic infections. Quorum sensing (QS) is one of the prime mechanisms that control the virulence in Y. enterocolitica .

Hypothesis/Gap Statement. Vanillic acid inhibits the quorum sensing and other virulence factors related to Y. enterocolitica . It has been evaluated by transcriptomic and Insilico analysis. Therefore, it can be a prospective agent to develop a therapeutic combination against Y. enterocolitica .

Aim. The present study is focused on screening natural anti-quorum-sensing agents against Y. enterocolitica . The effect of selected active principle on various virulence factors was evaluated.

Methodology. In total, 12 phytochemicals were screened by swarming assay. MATH assay, EPS and surfactant production assay, SEM analysis, antibiotic and blood sensitivity assay were performed to demonstrate the anti-virulence activity. Further, RNA sequencing and molecular docking studies were carried out to substantiate the anti-QS activity.

Results. Vanillic acid (VA) has exhibited significant motility inhibition, thus indicating the anti-QS activity with MQIC of 400 µg ml−1 without altering the cell viability. It has also inhibited the violacein production in Chromobacterium violaceum ATCC 12472, which further confirms the anti-QS activity. VA has inhibited 16 % of cell-surface hydrophobicity (CSH), 52 % of EPS production and 60 % of surfactant production. Moreover, it has increased the sensitivity of Y. enterocolitica towards antibiotics. It has also made the cells upto 91 % more vulnerable towards human immune cells. The transcriptomic analysis by RNA sequencing revealed the down regulation of genes related to motility, virulence, chemotaxis, siderophores and drug resistance. VA treatment has also positively regulated the expression of several stress response genes. In furtherance, the anti-QS potential of VA has been validated with QS regulatory protein YenR by in silico molecular simulation and docking study.

Conclusion. The present study is possibly the first attempt to demonstrate the anti-QS and anti-pathogenic potential of VA against Y. enterocolitica by transcriptomic and in silico analysis. It also deciphers that VA can be a promising lead to develop biopreservative and therapeutic regimens to treat Y. enterocolitica infections.

A comprehensive review on the prevalence, pathogenesis and detection ofYersinia enterocolitica

Food safety is imperative for a healthy life, but pathogens are still posing a significant life threat. “Yersiniosis” is caused by a pathogen named Yersinia enterocolitica and is characterized by diarrheal, ileitis, and mesenteric lymphadenitis types of sicknesses. This neglected pathogen starts its pathogenic activity by colonizing inside the intestinal tract of the host upon the ingestion of contaminated food. Y. enterocolitica remains a challenge for researchers and food handlers due to its growth habits, low concentrations in samples, morphological similarities with other bacteria and lack of rapid, cost-effective, and accurate detection methods. In this review, we presented recent information about its prevalence, biology, pathogenesis, and existing cultural, immunological, and molecular detection approaches. Our ultimate goal is to provide updated knowledge regarding this pathogen for the development of quick, effective, automated, and sensitive detection methods for the systematic detection of Y. enterocolitica.

Food safety is imperative for a healthy life, but pathogens are still posing a significant life threat.