Yersinia Strains Research Articles

Seasonal and spatial variations in concentration, diversity, and antibiotic resistance of ambient bioaerosols in an arid region

The airborne microbiome significantly influences human health and atmospheric processes within Earth's troposphere and is a crucial focus for scientific research. This study aimed to analyze the composition, diversity, distribution, and spatiotemporal characteristics of airborne microbes in Qatar's ambient air. Air samples were collected using a sampler from ten geographically or functionally distinct locations during a period of one year. Spatial and seasonal variations significantly impacted microbial concentrations, with the highest average concentrations observed at 514 ± 77 CFU/m3 for bacteria over the dry-hot summer season and 134 ± 31 CFU/m3 for fungi over the mild winter season. Bacterial concentrations were notably high in 80% of the locations during the dry-hot summer sampling period, while fungal concentrations peaked in 70% of the locations during winter. The microbial diversity analysis revealed several health-significant bacteria including the genera Chryseobacterium, Pseudomonas, Pantoea, Proteus, Myroides, Yersinia, Pasteurella, Ochrobactrum, Vibrio, and fungal strains relating to the genera Aspergillus, Rhizopus Fusarium, and Penicillium. Detailed biochemical and microscopic analyses were employed to identify culturable species. The strongest antibiotic resistance (ABR) was observed during the humid-hot summer season, with widespread resistance to Metronidazole. Health risk assessments based on these findings indicated potential risks associated with exposure to high concentrations of specific bioaerosols. This study provides essential baseline data on the natural background concentrations of bioaerosols in Qatar, offering insights for air quality assessments and forming a basis for public health policy recommendations, particularly in arid regions.

Influence of <i>Yersinia pestis</i> with different plasmid composition on the erythrocyte membrane in the blood of guinea pigs

Introduction. Based on data on the role of blood erythrocytes in the development and implementation of the vaccine and infectious processes in plague, it was of interest to evaluate changes in erythrocyte surface architecture from the position of searching for informative criteria for the preclinical evaluation of anti-plague vaccines. Aim — using atomic force microscopy to characterize the state of the blood erythrocyte membrane of guinea pigs in response to subcutaneous administration of the vaccine strain Yersinia pestis EV NIIEG and its isogenic derivatives. Materials and methods. For immunization of animals strain Y. pestis EV NIIEG (pYT+, pYV+, pYP+) and its isogenic derivatives Y. pestis KM216 (pYT–, pYV–, pYP+), Y. pestis KM217 (pYT–, pYV+, pYP–), Y. pestis KM218 (pYT–, pYV–, pYP–) were used. Analysis of the erythrocyte membrane was carried out using a Solver P47-PRO scanning probe microscope (NT-MDT, Russia). Results. The most pronounced changes in the surface architectonics of the membrane of guinea pig erythrocytes were established during the first three days of the formation of the immune response to the Y. pestis EV strain NIIEG and its isogenic variant Y. pestis KM217, in the genome of which the pYV plasmid is preserved, administered at a dose of 5 × 108 CFU. A significant increase (p 0.05) in the proportion of transformed cell forms (43.67 ± 3.63% and 37.83 ± 7.03% versus 4.08 ± 0.86% in the control group), root mean square roughness (319 ± 8 nm and 312 ± 7 nm versus 70 ± 6 nm in the control group), Young's modulus (125.73 ± 4.48 kPa and 113.8 ± 5.41 kPa versus 53.03 ± 1.47 kPa in the control group). By the 21st day, the value of these indicators decreased by an average of 2.7, 2.0 and 1.5 times, respectively, indicating restoration of the erythrocyte membrane. Conclusion. The dependence of the changes in the erythrocyte membrane and the rate of their restoration on the plasmid composition of Y. pestis strains has been established. The data obtained contribute to the understanding of the processes of interaction of Y. pestis with the erythrocyte membrane and can be used as additional characteristics in the development of new criteria for preclinical evaluation of plague candidate vaccines.

Possibility of Using Disposable Polymeric Containers in the Production Technology of Live Plague Vaccine

The aim of the work was to assess the possibility of using disposable polymeric containers in the production technology of the live plague vaccine.Materials and methods. We deployed the vaccine strain Yersinia pestis ЕV NIIEG for the work. A standard disposable 10 L Flexboy type polymeric container manufactured by Sartorius Stedim Biotech, equipped with Sartopore 2 filter capsules, was used for submerged cultivation of plague microbe inoculum. This method was compared to the regulated technology for obtaining seed cultures using glass bottles with a volume of 20 liters. The control of the produced seed cultures of the vaccine strain EV was performed in accordance with FS.3.3.1.0022.15. The cultivation of the seed culture in a disposable polymeric container was carried out in a liquid nutrient medium at a temperature of 26 to 28°C with continuous barbotage and mechanical agitation with a platform oscillation frequency of 80 to 90 per minute. For aeration, compressed air with a pressure of 0.3 to 0.4 kgf/cm2 was used. The volumetric flow rate of sterile air supplied for aeration ranged from 0.9 to 1.0 l/min.Results and discussion. The use of disposable polymeric containers made it possible to reduce the duration of the technological stage of obtaining a seed culture by 1.7 times and increase the yield of live microbes per unit volume of the nutrient medium by 2.8 times, as compared to the regulated production technology. Thus, the possibility and prospects of using disposable polymeric containers in the production technology of live plague vaccine at the stage of preparation of sowing cultures is evidenced.

Enteropathogenic Yersinia with Public Health Relevance Found in Dogs and Cats in Finland.

Yersiniosis is a common zoonotic enteric disease among humans, which has been linked to pigs and contaminated food, especially pork. The epidemiology of yersiniosis is still obscure, and studies on yersiniosis in pets are very scarce. In this study, we performed pheno- and genotypic characterisation of 50 Yersinia strains isolated from pets in Finland between 2012 and 2023. Y. enterocolitica 4/O:3/ST135, the most common type in human yersiniosis, was also the most common type (68%) found in clinical faecal samples in our study. Also, human pathogenic Y. enterocolitica 2/O:9/ST139 and Y. pseudotuberculosis O:1/ST9 and O:1/ST42 strains carrying all essential pathogenic genes were identified. Three Y. enterocolitica 4/O:3/ST9 strains were multi-drug-resistant and two of them were highly related, showing one allelic difference (AD) with core genome multi-locus sequence typing. Non-pathogenic, genotypically highly diverse Y. enterocolitica 1A strains, showing more than 1000 ADs and missing the essential virulence genes, were also recognised in dogs and cats. Our study demonstrates that pets can excrete human pathogenic Yersinia in their faeces and may serve as an infection source for human yersiniosis, especially in families with small children in close contact with their pets.

Whole-genome sequencing-based analysis of antimicrobial resistance, virulence factors, and genetic diversity in Yersinia isolated in Wenzhou, China 2020

Yersinia spp. vary significantly in their ability to cause diseases that threaten public health. Their pathogenicity is frequently associated with increasing antimicrobial resistance (AMR) and various virulence factors. The aim of the study was to investigate the AMR genes, virulence factors, and genetic diversity of Yersinia strains isolated from meats and fish in Wenzhou in 2020 by using whole-genome sequencing (WGS). A total of 50 isolates were collected. The phylogenetic relationships among the Yersinia species were also analyzed using multilocus sequence typing (MLST), core genome multi-locus sequence typing (cgMLST), and single nucleotide polymorphism (SNP) analysis. According to the results, all the strains could be classified into five species, with most isolated from beef, followed by poultry, pork, and fish. AMR genes were identified in 23 strains. And the qnrD1 genes were all located in the Col3M plasmid. Virulence genes, such as yaxA, ystB, pla, and yplA, were also found in the 15 Y. enterocolitica strains. And this study also found the presence of icm/dot type IVB-related genes in one Yersinia massiliensis isolate. MLST analysis identified 43 sequence types (STs), 19 of which were newly detected in Yersinia. Moreover, cgMLST analysis revealed that no dense genotype clusters were formed (cgMLST 5341, 5344, 5346–5350, 5353–5390). Instead, the strains appeared to be dispersed over large distances, except when multiple isolates shared the same ST. Isolates Y4 and Y26 were closely related to strains originating from South Korea and Denmark. This study showed considerable diversity in Yersinia spp. isolated from local areas (Wenzhou City). The data generated in our study may enrich the molecular traceability database of Yersinia and provide a basis for the development of more effective antipathogen control strategies.

The Influence of the Synthetic Organoselenium Preparation 974zh on the Immunogenic Activity of Yersinia pestis EV Vaccine Strain NIIEG.

In the present study, a stimulating effect of a new synthetic organoselenium compound 2,6-dipyridinium-9-selenabicyclo[3.3.1]nonandibromide (974zh) on the immunogenic activity of the vaccine strain Yersinia pestis EV NIIEG was revealed. After infection with the virulent plague strain, the survival rate of laboratory mice immunized with the vaccine strain grown on Hottinger's agar in the presence of 974zh (300 μg/ml) increased in comparison with control animals immunized with the Y. pestis EV NIIEG culture grown on agar without the studied compound. Plasmid screening of cultures grown on medium with and without 974zh showed that plasmid DNA of Y. pestis EV culture grown in the presence of 974zh had broader bands in the control grown without 974zh. This phenomenon can indicate activation of replication of plasmid DNA of Y. pestis EV under the influence of the experimental compound.

Natural foci of plague in Kazakhstan in the space-time continuum

The relevance of the problem of the stated topic lies in the fact that the causative agent of the plague infection demonstrates high survival while maintaining high virulence in the territories, which are enzootic in terms of the plague. The study aimed to investigate the geographic distribution and genetic diversity of the plague pathogen in endemic regions through molecular genetic research. The work included the results of laboratory studies of 3058 samples, including soil – 1154, burrow substrates – 549, the contents of the feeding chamber – 349, bone remains – 18, biological objects – 988 samples of sera and suspensions from carriers and vectors of plague infection collected from 14 autonomous plague foci of Kazakhstan for the period 2021–2022. The leading method in the study was a laboratory experiment, thanks to which, using a new advanced technology on a microbiological analyser VITEK 2 COMPACT 30, it was possible to study pathogenic and non-pathogenic strains of the genus Yersinia isolated during field experiment. As a result of experimental work, it was shown that during a long inter-epizootic period, the plague pathogen can persist in the soil in symbiosis with soil microorganisms, and in this area, it chooses soil with a low-quality index of 10 points, where soils with a low total microbial number and species landscape prevail.

Increased expression of tyrosine protein phosphatase (CD45) on the surface of human blood granulocytes under the influence of the plague microbe vaccine strain <I>Yersinia pestis</I> EV NIIEG <I>ex vivo</I> and <I>in vivo</I>

Tyrosine protein phosphatase (common leukocyte antigen CD45) regulates FcᵧR-mediated cell signaling and secretory function of neutrophilic granulocytes (NG) when interacting with antigen-antibody immune complexes. The aim of the work is to study changes in the expression of CD45 on the surface of human granulocytes in ex vivo modeling of bacteremia by live cells of the plague microbe vaccine strain Yersinia pestis EV NIIEG and to evaluate the priming effect of the live plague vaccine (LPV) in vivo in terms of this parameter. The expression density of CD45 on NG was determined by flow cytometry in conventional units of fluorescence intensity (MFI) after staining the cells with the CD45-FITC labeled mouse antibody reagent (Backman Coulter, USA) during immunophenotyping of blood leukocytes according to the Lyse/No Wash protocol. In donors not previously vaccinated against plague (group 1), the value of the indicator was assessed before and 30 min, 2 h, 6 h after the addition of Y pestis EV cells to whole blood at a dose of 108 mc/ml, as well as 1 month and 6 months after the primary anti-plague vaccination. In individuals who had previously been repeatedly vaccinated with LPV in the territory of the natural plague focus (group 2), CD45 expression on blood granulocytes was determined one year after the last annual vaccination, and then 1 month and 6 months after revaccination. Getting into human blood, living cells of the vaccine strain Y pestis EV of the plague microbe induced a change in the NC phenotype already after 30 minutes, associated with a 3.5-fold increase in the surface expression of CD45, which remained at an elevated level for 6 hours. The studied indicator depended ex vivo on the degree of resistance of plague microbes to phagocytosis and killing of NG. Plague vaccination had a similar stimulating effect on human peripheral blood NG in vivo. Under the influence of HPV, CD45 expression increased on blood NG in groups 1 and 2 one month after vaccination, and the changes persisted in volunteers for 6 months. The experimental data obtained in the work may reflect the result of NG priming with lipopolysaccharide and other Y. pestis antigens. The registered functional activation of NG by expression of tyrosine protein phosphatase probably indicates the formation of “immune memory” at the level of innate immunity cells under the influence of LPV, the functioning of which explains the development of a faster and more intense antigen-specific immune response to repeated introduction of the plague vaccine into the body.

Increasing the immunogenic and protective activity of the vaccine strain Yersinia pestis EV line NIIEG using synthetic immunomodulators

Introduction. One of the main tasks of specific plague prevention remains the development of vaccines and their application schemes aimed at improving the effectiveness of vaccination through the use of adjuvants and immunomodulators.
 The purpose of the study were comparative evaluation of the effect of drugs from the group of synthetic immunomodulators on the immunogenic and protective properties of the Yersinia pestis EV line NIIEG vaccine strain in model animal experiments.
 Materials and methods. White mice and guinea pigs were immunized with the vaccine strain Y. pestis EV line NIIEG. The animals of the experimental groups were injected with oligopeptides O1 (Threonyl-glutamyl-lysyl-lysyl-arginyl-arginyl-glutamyl-threonyl-valyl-glutamyl-arginyl-glutamyl-lysyl-glutamate), O2 (Glutamyl-cysteinyl-glycine disodium) and O3 (Arginyl-alpha-aspartyl-lysyl-valyl-tyrosyl-arginine) one hour before vaccination or three times before infection. On days 3, 14 and 21, antibody and cytokine products were studied. Animals were infected with the test strain Y. pestis 231(708) at a dose of 400 LD50.
 Results. It was found that a single administration of immunomodulators 1 hour before vaccination did not change the susceptibility of animals to the plague microbe: ImD50 = 5860 (O1); 5860 (O2); 6454 (O3) and 6876 (control) CFU for white mice and 446 (O1), 551 (O2), 446 (O3) and 578 (control) CFU for guinea pigs. Three-time administration of drugs to vaccinated animals led to a decrease in the ImD50 Y. pestis EV line NIIEG indicators in the group with O1 by 2.2 times (mice) and 1.8 times (guinea pigs), with O2 and O3 by 1.2 times, regardless of the biomodel compared with the control. The stimulating effect of O1 and O3 on the production of antibodies to F1 of the plague microbe and cytokines interferon-gamma, interleukin-10 has been established.
 Conclusion. The stimulating potential of synthetic immunomodulators on the immune system of biomodels immunized by Y. pestis EV line NIIEG has been demonstrated, which determines the prospects of research to improve the schemes of prophylactic vaccination against plague.

YsHyl8A, an Alkalophilic Cold-Adapted Glycosaminoglycan Lyase Cloned from Pathogenic Yersinia sp. 298.

A high enzyme-yield strain Yersinia sp. 298 was screened from marine bacteria harvested from the coastal water. The screening conditions were extensive, utilizing hyaluronic acid (HA)/chondroitin sulfate (CS) as the carbon source. A coding gene yshyl8A of the family 8 polysaccharide lyase (PL8) was cloned from the genome of Yersinia sp. 298 and subjected to recombinant expression. The specific activity of the recombinase YsHyl8A was 11.19 U/mg, with an optimal reaction temperature of 40 °C and 50% of its specific activity remaining after thermal incubation at 30 °C for 1 h. In addition, its optimal reaction pH was 7.5, and while it was most stable at pH 6.0 in Na2HPO4-citric acid buffer, it remained highly stable at pH 6.0–11.0. Further, its enzymatic activity was increased five-fold with 0.1 M NaCl. YsHyl8A, as an endo-lyase, can degrade both HA and CS, producing disaccharide end-products. These properties suggested that YsHyl8A possessed both significant alkalophilic and cold-adapted features while being dependent on NaCl, likely resulting from its marine source. Yersinia is a typical fish pathogen, with glycosaminoglycan lyase (GAG lyase) as a potential pathogenic factor, exhibiting strong hyaluronidase and chondroitinase activity. Further research on the pathogenic mechanism of GAG lyase may benefit the prevention and treatment of related diseases.

Antimicrobial Activity Derivatives 2H-pirano[2,3-c]piridines against Pathogens of Intestinal Yersiniosis

Background: An important aspect in the treatment of patients with intestinal yersiniosis is the administration of effective antibiotic therapy. Performed research aimed to determine the spectrum and level of antimicrobial activity of 2H-pyrano[2,3- c]pyridine derivatives on the museum and clinical strains of gram-negative microorganisms Yersinia enterocolitica. Methodology: The object of the study was 28 synthetic derivatives of 2H-pyrano[2,3- c]pyridine. The compounds were studied according to their chemical structure. We used the method of serial dilutions in Muller-Hinton liquid nutrient medium with a museum’s and clinical strains of Y.enterocolitica. Results: Studies indicate the promise of further study of the properties of 2H- pyrono[2,3-c]pyridine to create an effective antimicrobial medicine. According to the results of studies on action of antimicrobial compounds synthesized on the basis of 2H-pyrano[2,3-с]pyridine derivatives, it was found that the MIC of compounds for all Y. enterocolitica strains was 100.0 μg/ml. The MBCC of most cultures of Yersinia (72.3 %) was 200.0 μg/ml. Compound 2{3} had a pronounced antiyersiniotic activity, the inhibitory effect of which was manifested at a concentration of 25.0 μg/ml. Retarding the growth of most Yersinia strains (95.3%) with a MIC of 50.0 μg/ml, the MIC of compounds ranged from 50.0 to 200.0 μg/ml. After statistical data processing, pyridine derivatives (compounds 2{3} and 3{5}) were identified, possessing an effective bacteriostatic and bactericidal effect on Y. enterocolitica strains. Conclusions: The results of the research showed a high antimicrobial activity of 2H- pyrano[2,3-c]pyridine derivatives. The highest activity against Y. enterocolitica was found for 2-N2-arylimino-5-hydroxy-methyl-8-methyl-2H-pyrano[2,3-c]pyridine-3-N1- aricarboxamide derivatives.

Elastic Light Scatter Pattern Analysis for the Expedited Detection of Yersinia Species in Pork Mince: Proof of Concept.

Isolation of the pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis from foods typically rely on slow (10–21 day) “cold enrichment” protocols before confirmed results are obtained. We describe an approach that yields results in 39 h that combines an alternative enrichment method with culture on a non-selective medium, and subsequent identification of suspect colonies using elastic light scatter (ELS) analysis. A prototype database of ELS profiles from five Yersinia species and six other bacterial genera found in pork mince was established, and used to compare similar profiles of colonies obtained from enrichment cultures from pork mince samples seeded with representative strains of Y. enterocolitica and Y. pseudotuberculosis. The presumptive identification by ELS using computerised or visual analyses of 83/90 colonies in these experiments as the target species was confirmed by partial 16S rDNA sequencing. In addition to seeded cultures, our method recovered two naturally occurring Yersinia strains. Our results indicate that modified enrichment combined with ELS is a promising new approach for expedited detection of foodborne pathogenic yersiniae.

Phenotypic and molecular characterization of quinolone resistance of enteropathogens isolated from diarrhea in young children in Koula-Moutou/Gabon

ABSTRACT In the face of the growing phenomenon of multidrug-resistant bacteria, studies on the sensitivity profiles of enteric pathogens are required to better manage the remaining antibiotic capital. The objective of this study was to investigate the sensitivity and to determine the genetic basis of quinolone-resistant enteric diarrheal pathogens isolated from children in the city of Koula-Moutou, Gabon. Thirty strains of the Salmonella genera, five strains of Shigella and two strains of Yersinia (2) were analyzed. The Kirby–Bauer method was used to determine the sensitivity of these isolates to five molecules in the quinolone family. The presence of chromosomal (gyrA) and plasmid (PMQR) quinolone resistance genes, including the QNR complex (qnrA, qnrB, and qnrS) were investigated by PCR. These enteric pathogens exhibited high levels of resistance to quinolones, particularly ofloxacin (100%) and ciprofloxacin (97.3%). Most isolates of Salmonella were found to be resistant to nalidixic acid (86.7%), however all isolates of the Shigella and Yersinia genera were susceptible to this antibiotic. Among the 37 strains, 21.6% had the gyrA gene, 13.5% had the qnrB and qnrS genes but the qnrA gene was not detected. Enteric pathogens isolated from the diarrheal feces of the children in Koula-Moutou exhibited high levels of phenotypic resistance to quinolones. This resistance is especially due to mutations occurring on the chromosomal determinant gyrA which also played a role in the reduced sensitivity of these strains to fluoroquinolones. The resistance is also linked to a lesser extent to the acquisition of the PMQR genes, notably qnrB and qnrS. In conclusion, this study highlights the high prevalence rate of enteric pathogens isolated from diarrheal feces of children in Gabon and shows the presence of the QNR complex genes (qnrB and qnrS) in the strains.

Development of an Enteric Bacterial Enrichment Broth and Its Performance for Isolation of Clinically Significant Bacterial Pathogens from Stool

Background: Early detection and accurate identification of foodborne pathogen outbreaks is an important public health function. Increased clinical adoption of multiplex PCR assays or culture independent diagnostic tests (CIDT) correlates to more stool specimens sent to public health laboratories (PHL) for characterization. Isolation and confirmation of enteric bacterial pathogens can prove difficult to consistently recover. The purpose of this study was to evaluate the performance of a broad-use laboratory developed enrichment broth for isolation of Campylobacter, Salmonella, Shigella, and Yersinia strains from stool specimens. Methods: The study compared differences in positivity rates among media and enrichment combinations at specific time points. Comparison of direct inoculation (DI), enrichment using a lab-developed Enteric Bacterial Enrichment (EBE) broth and gold-standard isolation methods were conducted to test current utility of this established practice with stool specimens heat injured and non-injured. Results: A total of 234 spiked stool samples, 175 non-injured and 59 heat injured, were tested with varying bacterial concentrations. For non-injured stools, direct inoculation performed better for Campylobacter and Yersinia than enrichment. Conversely, Salmonella and Shigella recovery and limit of detection increased with enrichment. Campylobacter had the highest percent recovery while Shigella being the lowest from direct plating at 6-hour and 24-hour enrichment periods. Among broths, EBE performed the best for Yersinia and similar to Selenite broth for Salmonella and Shigella. Generally, heat injured stool had a significantly lower percent of recovery than non-heat injured with a higher limit of detection across organisms. Conclusion: Our data suggest there is an only utility for targeted enrichment of CIDT positive Salmonella stool specimens. We highlight the difficulties of formulating an enrichment broth capable of supporting a variety of enteric pathogens with standardized incubation. Increasing demands on PHL infrastructure warrant further examination of enhancing organism isolation and cost analyses for CIDT positive specimens.

Monitoring and Analysis of Drug Resistance of Yersinia in Fresh Meat

Objective To monitor the drug resistance status of yersinia isolates from fresh meat, grasp the drug resistance spectrum and trend of Yersinia isolates in Our province, and provide important reference data for guiding the rational application of antibiotics in human clinical practice and controlling the spread of drug resistant strains. Methods A total of 600 pieces of fresh pork, beef and chicken were collected from several farmers' markets and supermarkets in Changchun every month for 15 months from August 18th to October 19th. 80 strains of Yersinia strains were detected, and MIC concentrations of drug resistance were detected by microbroth dilution with 15 antibiotic sensitive plates. Results 80 strains of Yersinia strains were counted. The total drug resistance rate of Yersinia pestis was 98.8%, and cefazolin (CFZ) had the highest drug resistance rate of 92.5.% (74/80). Erythromycin (ERY) was followed by 58.8% (47/80). Ampicillin (AMP) 57.5% (46/80); Naproxil acid (NAL) and cefoxitin (CFX) were 28.8 (23/80) and were somewhat resistant to other antibiotics. But all strains were sensitive to imipenem (IMP) and gentamicin (GEN). There were 28 strains with multiple drug resistance, accounting for 35.4% (28/79). Conclusion There are multiple antibiotic resistance in Yersinia strains in this monitoring, and the multiple drug resistance is serious and the resistance spectrum is diverse. In order to ensure food safety and human health, great attention should be paid to and enhanced drug resistance monitoring of Yersinia.

Multiplex PCR method for differentiating highly pathogenic Yersinia enterocolitica and low pathogenic Yersinia enterocolitica, and Yersinia pseudotuberculosis.

A multiplex PCR method for rapid and sensitive diagnosis, differentiating three pathogenic Yersinia groups such as the highly pathogenic Y. enterocolitica, including serotype O8, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis, was developed. Four primer pairs were chosen to detect the genes fyuA, ail, inv, and virF, responsible for the virulence in pathogenic Yersinia species. Under the multiplex PCR conditions, the unique band patterns for the highly pathogenic Y. enterocolitica, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis were generated from Yersinia strains. The detection limit of this method was 101–103 CFU per reaction tube. This multiplex PCR method could detect highly pathogenic Y. enterocolitica O8 from the wild rodent fecal samples that were culture-positive. Therefore, the new multiplex PCR method developed in this study is a useful tool for rapid and sensitive diagnosis, distinguishing three pathogenic Yersinia groups.

Computational Model Informs Effective Control Interventions against Y. enterocolitica Co-Infection.

Simple SummaryMedical control strategies for infectious diseases remain enormously important. One germ that can cause gastrointestinal infections is Yersinia enterocolitica. This study investigates and analyzes a computational model to identify the occurrence of disease-free and co-infection states. Thereby, the reproduction number informs us about the germ’s ability to spread disease. Suppose this fundamental quantity takes a value between zero and one. In that case, every infectious strain will cause less than one secondary infection, so the strain will disappear. In contrast, if exceeds one, every infectious strain causes more than one secondary infection, and Yersinia infection strains will persist. A disease-free state occurs when the commensal bacteria’s growth rate exceeds the maximum immune action and the rate at which the intestines release the bacteria. With a large enough commensal bacteria growth rate, this state can be stable. Co-infection occurs when the maximum growth rates of the wild-type and mutant strains become unequal. Studying the immune system’s behavior can result in an infection’s disappearance from hosts with a healthy microbiota immune system. In this case, Yersinia strains do not spread in the lumen when the commensal bacteria’s growth rate exceeds the growth rate of wild-type and mutant Yersinia.The complex interplay between pathogens, host factors, and the integrity and composition of the endogenous microbiome determine the course and outcome of gastrointestinal infections. The model organism Yersinia entercolitica (Ye) is one of the five top frequent causes of bacterial gastroenteritis based on the Epidemiological Bulletin of the Robert Koch Institute (RKI), 10 September 2020. A fundamental challenge in predicting the course of an infection is to understand whether co-infection with two Yersinia strains, differing only in their capacity to resist killing by the host immune system, may decrease the overall virulence by competitive exclusion or increase it by acting cooperatively. Herein, we study the primary interactions among Ye, the host immune system and the microbiota, and their influence on Yersinia population dynamics. The employed model considers commensal bacterial in two host compartments (the intestinal mucosa the and lumen), the co-existence of wt and mut Yersinia strains, and the host immune responses. We determine four possible equilibria: disease-free, wt-free, mut-free, and co-existence of wt and mut in equilibrium. We also calculate the reproduction number for each strain as a threshold parameter to determine if the population may be eradicated or persist within the host. We conclude that the infection should disappear if the reproduction numbers for each strain fall below one, and the commensal bacteria growth rate exceeds the pathogen’s growth rate. These findings will help inform medical control strategies. The supplement includes the MATLAB source script, Maple workbook, and figures.

Two copies of the ail gene found in Yersinia enterocolitica and Yersinia kristensenii

Yersinia enterocolitica is the most common Yersinia species causing foodborne infections in humans. Pathogenic strains carry the chromosomal ail gene, which is essential for bacterial attachment to and invasion into host cells and for serum resistance. This gene is commonly amplified in several PCR assays detecting pathogenic Y. enterocolitica in food samples and discriminating pathogenic isolates from non-pathogenic ones. We have isolated several non-pathogenic ail-positive Yersinia strains from various sources in Finland. For this study, we selected 16 ail-positive Yersinia strains, which were phenotypically and genotypically characterised. Eleven strains were confirmed to belong to Y. enterocolitica and five strains to Yersinia kristensenii using whole-genome alignment, Parsnp and the SNP phylogenetic tree. All Y. enterocolitica strains belonged to non-pathogenic biotype 1A. We found two copies of the ail gene (ail1 and ail2) in all five Y. kristensenii strains and in one Y. enterocolitica biotype 1A strain. All 16 Yersinia strains carried the ail1 gene consisting of three different sequence patterns (A6-A8), which were highly similar with the ail gene found in high-pathogenic Y. enterocolitica biotype 1B strains (A2). The Ail protein encoded by the ail1 gene was highly conserved compared to the Ail protein encoded by the ail2 gene. Multiple sequence alignment of the ail gene and Ail protein were conducted with MAFF. In total, 10 ail sequence variations have been identified, of which 8 conserved ones belonged to the ail1 gene. According to our results, the detection of ail alone is not sufficient to predict the pathogenicity of Yersinia isolates.

Identification of a Novel Yersinia enterocolitica Strain from Bats in Association with a Bat Die-Off That Occurred in Georgia (Caucasus).

Yersinia entercolitica is a bacterial species within the genus Yersinia, mostly known as a human enteric pathogen, but also recognized as a zoonotic agent widespread in domestic pigs. Findings of this bacterium in wild animals are very limited. The current report presents results of the identification of cultures of Y. entercolitica from dead bats after a massive bat die-off in a cave in western Georgia. The growth of bacterial colonies morphologically suspected as Yersinia was observed from three intestine tissues of 11 bats belonging to the Miniopterus schreibersii species. These three isolates were identified as Y. enterocolitica based on the API29 assay. No growth of Brucella or Francisella bacteria was observed from tissues of dead bats. Full genomes (a size between 4.6–4.7 Mbp) of the Yersinia strains isolated from bats were analyzed. The phylogenetic sequence analyses of the genomes demonstrated that all strains were nearly identical and formed a distinct cluster with the closest similarity to the environmental isolate O:36/1A. The bat isolates represent low-pathogenicity Biotype 1A strains lacking the genes for the Ail, Yst-a, Ysa, and virulence plasmid pYV, while containing the genes for Inv, YstB, and MyfA. Further characterization of the novel strains cultured from bats can provide a clue for the determination of the pathogenic properties of those strains.

The Prevalence of Yersinia enterocolitica and Yersinia pseudotuberculosis in Small Wild Rodents in Poland.

Rodents are a large group of mammals that can be carriers of zoonotic pathogens such as Yersinia strains that cause yersiniosis. The prevalence of Yersinia enterocolitica and Yersinia pseudotuberculosis was determined in 214 small wild rodents from south-eastern Poland. Samples were analyzed by precultivation and PCR. Nine (4.2%) Y. enterocolitica and one (0.5%) Y. pseudotuberculosis isolates were received. Most of them (n = 5) were obtained from the common vole (Microtus arvalis). All Y. enterocolitica strains were classified as biotype (BT) 1A. A PCR analysis of virulence markers revealed that all Y. enterocolitica isolates contained the ystB gene and five isolates harbored a rare genetic combination of ail/ystB. Three of the four ail/ystB-positive isolates belonged to serotype O:5.27. The Y. pseudotuberculosis inv-positive isolate was classified as BT 1. A genetic analysis of Y. enterocolitica harboring the ystB gene revealed 100% similarity between the analyzed sequences and the sequences from diarrhea patients in India and the United Kingdom as well as high similarity with the sequences from different species of wild animals from Poland. The Y. pseudotuberculosis inv sequence was 100% identical to the sequence isolated from fully virulent clinical strain from France and Australia. The results of our study suggest that small wild rodents, especially voles and yellow-necked mice, may act as carriers of Yersinia strains. The high similarity of the tested gene sequences between our isolates and the isolates from other free-living animals indicates that small wild rodents can play a role in the epidemiology of yersiniosis and can shed Yersinia spp. into the environment.