Foodborne illness is an escalating concern upon public health. The prevalence of Yersinia enterocolitica was assessed in chitterlings, raw milk and swine fecal from North Carolina. Uncleaned thirty chitterling samples...Foodborne illness is an escalating concern upon public health. The prevalence of Yersinia enterocolitica was assessed in chitterlings, raw milk and swine fecal from North Carolina. Uncleaned thirty chitterling samples procured from a local grocery store, forty-five swine fecal samples, and forty unpasteurized cow milk samples supplied by the University farm were evaluated for the presence of Y. enterocolitica. Isolates identified as presumptive positive were characterized as colonies with a pink or deep-red center on MacConkey and CIN agar, and verified further through polymerase chain reaction (PCR) for the presence of 16S rRNA gene for the Yersinia genera. Results showed that 4.4% swine fecal samples, 7.5% milk samples and 11.3% chitterling samples were presumptive positive for Y. enterocolitica by the direct plating method on selective agars. Of the thirty-chitterling samples examined by PCR for the 16S rRNA gene, 26% samples contained the identification gene for the bacteria of interest. After conducting virulence tests, the fecal samples were revealed as non-pathogenic. Only one of the milk samples were considered pathogenic and consisted of the following virulent genes: Yersinia heat-stable toxin (yst), invasion (inv), attachment invasion locus (ail), virulence regulon transcriptional activator (virF), Yersinia adehesin A (yadA), and the O:3 antigen gene (rfbC). Seven out of the eight (87.5%) chitterling samples were shown to be pathogenic. Disc diffusion was conducted to determine the antimicrobial susceptibility of the isolates. Over half (55.5%) of the antimicrobial agents were found effective, with isolates being completely susceptible to ciprofloxacin, kanamycin, trimethoprim, cefotaxime, and gentamycin. Ampicillin was determined to be least effective, where 84.6% of the samples presented resistance to the drug. Random amplified polymorphic DNA (RAPD) analysis and ERIC-PCR techniques were used to evaluate genetic similarity among the Yersinia isolates. There was approximately 85% similarity between two chitterlings and a fecal isolate during RAPD testing. With ERIC-PCR the largest similarity among all samples was at 95%, which was found between isolates from a chitterling and milk sample. Chitterling samples showed the highest prevalence of Y. enterocolitica compared to the other samples. Cross contamination at the farm level could be the root cause of this pathogen being prevalent in farm animal and food sources, which does pose a risk to public human health when food is improperly prepared.展开更多
Objective Yersinia enterocolitica is an extracellular pathogen and its related antigens interact with the host immune system. We investigated the difference in immunological characteristics between a highly pathogenic...Objective Yersinia enterocolitica is an extracellular pathogen and its related antigens interact with the host immune system. We investigated the difference in immunological characteristics between a highly pathogenic and poorly pathogenic strain of Y. enterocolitico. Methods We used SDS-PAGE and western blotting to characterize lipopolysaccharide （LPS）, Yersinio outer membrane proteins （Yops）, membrane proteins, and whole-cell proteins from poorly pathogenic Y. enterocolitico bio-serotype 2/0：9, isolated from China, and highly pathogenic bio-serotype 1B/O：8, isolated from Japan. Results These two strains of Y. enterocolitica had different LPS immune response patterns. Comparison of their Yops also showed differences that could have accounted for their differences in pathogenicity. The membrane and whole-cell proteins of both strains were similar; immunoblottting showed that the 35 kD and perhaps the 10 kD proteins were immunogens in both strains. Conclusion The major antigens of the two strains e and membrane proteins, as shown by comparing preparations. citing the host immune protein samples with response were the LPS reference and purified展开更多
Objective To analyze the impact of depletion of the twin arginine translocation （TAT） system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity. Methods We constru...Objective To analyze the impact of depletion of the twin arginine translocation （TAT） system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity. Methods We constructed a △tatC：：Sp^R mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 △tatC：：Sp^R strain as a donor. Results A Pl-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type E enterocolitica strain and translocation of this enzyme was completely abolished by the △tatC：：Sp^R mutation. In addition, the △tatC：：Sp^R mutation showed a pleiotropic effect on the metabolism of E enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used. Conclusion Unlike other pathogenic bacteria studied, the TAT system of E enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O 157：H7.展开更多
Yersinia enterocolitica is an important zoonotic pathogen that can induce disease outbreaks in a wide host range. Strain YER6022 was isolated from Pelteobagrus vachelli and identified using bacterial morphology and 16...Yersinia enterocolitica is an important zoonotic pathogen that can induce disease outbreaks in a wide host range. Strain YER6022 was isolated from Pelteobagrus vachelli and identified using bacterial morphology and 16S rDNA sequence analysis. Five virulence factors were detected, then artificial infection experiment and histopathological method were carried out. These results showed that strain YER6022 was one of Y. enterocolitica family members. In addition, ail, ystb, virF, yadA and HPIint were dectected. In artificial infection experiment, with 80% mortality and 100% morbidity, injected Pelteobagrus vachellis showed red swollen of the anus, abdomen swelling and fim bleeding. There existed serious hyperaemia and edema in kidney, spleen, intestine and liver at the light microscope. Ultrastructural observation indicated that mitochondria of the liver, kidney, spleen and intestine swelled and mitochondrial cristae broke. The data had further shed light on its pathogenicity in Pelteobagrus vachelli. It would benefit for further studies on pathogenesis ofPelteobagrus vachelli infected with Y. enterocolitica.展开更多
The public health significance of Yersinia spp. gives a new dimension to the prevailing food chain, wherein the foods do get exposed to heat and cold treatments. In this study, the effect of heat treatment on the nati...The public health significance of Yersinia spp. gives a new dimension to the prevailing food chain, wherein the foods do get exposed to heat and cold treatments. In this study, the effect of heat treatment on the native isolates of Yersinia enterocolitica CFR 2301 and Y. intermedia CFR 2303 revealed the D-values ranging from the lowest of 0.08 min at 65℃ in skim milk/beef gravy to the highest of 18.52 min at 50℃ in beef gravy. The heat sensitivity of both these cultures was in the order of Milli-Q water > 0.85% saline > skim milk > beef gravy. The z-values of the test cultures ranged from 7.55℃ for Y. intermedia to 12.08℃ for Y. enterocolitica. The heat sensitivity in Y. enterocolitica appeared to be related with growth incubation temperatures and also fatty acid profile of cell membrane. The effect of low temperature treatments (–20 ℃, 0℃ and 4℃ for 20 d) in water, saline and skim milk revealed the ability of Y. enterocolitica to survive more efficiently at –20℃, while Y. intermedia was more tolerant at 0℃. In packaged drinking water, Y. enterocolitica could survive and grow at 4℃ and 16℃, while at 30℃, inactivation was rapid. The findings did indicate that heat and cold treatments would not always ensure safety from Y. enterocolitica and Y. intermedia in the food chain.展开更多
The purpose of this study was to evaluate the storage conditions as a way to increase the safety of fermented sausage, with the specific objectives to investigate the effect of storage time, pH value, water activity a...The purpose of this study was to evaluate the storage conditions as a way to increase the safety of fermented sausage, with the specific objectives to investigate the effect of storage time, pH value, water activity and microbiological status （Lactobacillus spp and Enterobacteriaceae） on the levels of Yersinia enterocolitica in fermented sausages. For this experiment, meat was divided into four equal portions of 10 kg each. The first portion was control group （C1 group） without addition of Y. enterocolitica and starter culture. The second portion （CII group） was inoculated starter, the third portion （EI group） was inoculated with I1. enterocolitica and the fourth portion （Eli group） was inoculated Y.. enterocolitica and starter culture. Sampling was performed by randomly selecting two links of each sausage preparation at the 0, 3rd, 6th, 9th, 15th, 25th and 35th day of drying. Results show that Y. enterocolitica and Enterobacteriaceae were not detected after 25 d of storage. The results indicate that practice utilizing starter culture is satisfactory to reduction of pathogen if present. Thus, inclusion with starter cultures in a maturation period may increase the safety of fermented sausages.展开更多
In December 2017, two suspected outbreaks of <em>Yersinia enterocolitica </em>4/O:3 were notified in Finland. We analyzed the surveillance and outbreak investigation data and genotyped <em>Y. enteroc...In December 2017, two suspected outbreaks of <em>Yersinia enterocolitica </em>4/O:3 were notified in Finland. We analyzed the surveillance and outbreak investigation data and genotyped <em>Y. enterocolitica</em> strains in order to understand <em>Y. enterocolitica</em> epidemiology in Finland and to find out whether the notified outbreaks were related. A total of 13,344 <em>Y. enterocolitica</em> cases were reported in 1995-2018 to the National Infectious Diseases Register. The mean annual incidence ranged from 7.9 to 15.9/100,000 inhabitants. The highest incidence was observed in young adults (14/100,000). Incidence varied geographically. The incidence was higher in spring compared to other seasons. The most common pathogenic bioserotype was 4/O:3 but the information on bio/serotype was missing in 64% of the surveillance cases. For most of the cases, 87%, no travel history was reported. In the YE 4/O:3 outbreak investigation, whole genome sequencing was performed for isolates from 29/69 (42%) of the outbreak cases. The sequencing results showed that cases consisted of six independent clusters with 2 - 6 isolates in each cluster, and 5 sporadic isolates. No food item was found to be common to all of the clusters. In order to improve monitoring and facilitate the detection and investigation of<em> Y. enterocolitica</em> outbreaks, more comprehensive information on bio/serotype and on travel history is required in the surveillance.展开更多
Prosthetic joint infection is a rare manifestation of Yersinia enterocolitica. We report a case of a patient presenting with fever and a purulent infection in his prosthetic knee joint caused by Y. enterocolitica. He ...Prosthetic joint infection is a rare manifestation of Yersinia enterocolitica. We report a case of a patient presenting with fever and a purulent infection in his prosthetic knee joint caused by Y. enterocolitica. He had been operated in 1990 for arthrosis of the right knee. Re-operation was performed in 2007 for loosening of the prosthesis. Seven months later, following progressively increasing knee pain, he became acutely febrile and a purulent knee joint infection was diagnosed. Y. enterocolitica was isolated from the joint fluid. Serum antibodies against Y. enterocolitica were also positive. He was treated with debridement, replacement of the liner component of the prosthesis and a long course of intravenous antimicrobial therapy. The infection was thought to be in a chronic suppressive state. The final outcome after all therapy was good.展开更多
Background Yersinia enterocolitica has been sporadically recovered from animals,foods,and human clinical samples in various regions of Ningxia,China.However,the ecological and molecular characteristics of Y.enterocoli...Background Yersinia enterocolitica has been sporadically recovered from animals,foods,and human clinical samples in various regions of Ningxia,China.However,the ecological and molecular characteristics of Y.enterocolitica,as well as public health concerns about infection in the Ningxia Hui Autonomous Region,remain unclear.This study aims to analyze the ecological and molecular epidemiological characteristics of Y.enterocolitis in order to inform the public health intervention strategies for the contains of related diseases.Methods A total of 270 samples were collected for isolation[animals(n=208),food(n=49),and patients(n=13)],then suspect colonies were isolated and identified by the API20E biochemical identification system,serological tests,biotyping tests,and 16S rRNA-PCR.Then,we used an ecological epidemiological approach combined with machine learning algorithms(general linear model,random forest model,and eXtreme Gradient Boosting)to explore the associations between ecological factors and the pathogenicity of Y.enterocolitis.Furthermore,average nucleotide identity(ANI)estimation,single nucleotide polymorphism(SNP),and core gene multilocus sequence typing(cgMLST)were applied to characterize the molecular profile of isolates based on whole genome sequencing.The statistical test used single-factor analysis,Chi-square tests,t-tests/ANOVA-tests,Wilcoxon rank-sum tests,and Kruskal–Wallis tests.Results A total of 270 isolates of Yersinia were identified from poultry and livestock(n=191),food(n=49),diarrhoea patients(n=13),rats(n=15),and hamsters(n=2).The detection rates of samples from different hosts were statistically different(χ^(2)=22.636,P<0.001).According to the relatedness clustering results,270 isolates were divided into 12 species,and Y.enterocolitica(n=187)is a predominated species.Pathogenic isolates made up 52.4%(98/187),while non-pathogenic isolates made up 47.6%(89/187).Temperature and precipitation were strongly associated with the pathogenicity of the isolates(P<0.001).The random forest(RF)prediction model showed the best performance.The prediction result shows a high risk of pathogenicity Y.enterocolitica was located in the northern,northwestern,and southern of the Ningxia Hui Autonomous Region.The Y.enterocolitica isolates were classified into 54 sequence types(STs)and 125 cgMLST types(CTs),with 4/O:3 being the dominant bioserotype in Ningxia.The dominant STs and dominant CTs of pathogenic isolates in Ningxia were ST429 and HC100_2571,respectively.Conclusions The data indicated geographical variations in the distribution of STs and CTs of Y.enterocolitica isolates in Ningxia.Our work offered the first evidence that the pathogenicity of isolates was directly related to fluctuations in temperature and precipitation of the environment.CgMLST typing strategies showed that the isolates were transmitted to the population via pigs and food.Therefore,strengthening health surveillance on pig farms in high-risk areas and focusing on testing food of pig origin are optional strategies to prevent disease outbreaks.展开更多
文摘Foodborne illness is an escalating concern upon public health. The prevalence of Yersinia enterocolitica was assessed in chitterlings, raw milk and swine fecal from North Carolina. Uncleaned thirty chitterling samples procured from a local grocery store, forty-five swine fecal samples, and forty unpasteurized cow milk samples supplied by the University farm were evaluated for the presence of Y. enterocolitica. Isolates identified as presumptive positive were characterized as colonies with a pink or deep-red center on MacConkey and CIN agar, and verified further through polymerase chain reaction (PCR) for the presence of 16S rRNA gene for the Yersinia genera. Results showed that 4.4% swine fecal samples, 7.5% milk samples and 11.3% chitterling samples were presumptive positive for Y. enterocolitica by the direct plating method on selective agars. Of the thirty-chitterling samples examined by PCR for the 16S rRNA gene, 26% samples contained the identification gene for the bacteria of interest. After conducting virulence tests, the fecal samples were revealed as non-pathogenic. Only one of the milk samples were considered pathogenic and consisted of the following virulent genes: Yersinia heat-stable toxin (yst), invasion (inv), attachment invasion locus (ail), virulence regulon transcriptional activator (virF), Yersinia adehesin A (yadA), and the O:3 antigen gene (rfbC). Seven out of the eight (87.5%) chitterling samples were shown to be pathogenic. Disc diffusion was conducted to determine the antimicrobial susceptibility of the isolates. Over half (55.5%) of the antimicrobial agents were found effective, with isolates being completely susceptible to ciprofloxacin, kanamycin, trimethoprim, cefotaxime, and gentamycin. Ampicillin was determined to be least effective, where 84.6% of the samples presented resistance to the drug. Random amplified polymorphic DNA (RAPD) analysis and ERIC-PCR techniques were used to evaluate genetic similarity among the Yersinia isolates. There was approximately 85% similarity between two chitterlings and a fecal isolate during RAPD testing. With ERIC-PCR the largest similarity among all samples was at 95%, which was found between isolates from a chitterling and milk sample. Chitterling samples showed the highest prevalence of Y. enterocolitica compared to the other samples. Cross contamination at the farm level could be the root cause of this pathogen being prevalent in farm animal and food sources, which does pose a risk to public human health when food is improperly prepared.
基金supported by National Natural Science Foundation of China (General Project,No. 30970094)National Sci-Tech Key Project (2009ZX10004-201,2009ZX10004-203)
文摘Objective Yersinia enterocolitica is an extracellular pathogen and its related antigens interact with the host immune system. We investigated the difference in immunological characteristics between a highly pathogenic and poorly pathogenic strain of Y. enterocolitico. Methods We used SDS-PAGE and western blotting to characterize lipopolysaccharide （LPS）, Yersinio outer membrane proteins （Yops）, membrane proteins, and whole-cell proteins from poorly pathogenic Y. enterocolitico bio-serotype 2/0：9, isolated from China, and highly pathogenic bio-serotype 1B/O：8, isolated from Japan. Results These two strains of Y. enterocolitica had different LPS immune response patterns. Comparison of their Yops also showed differences that could have accounted for their differences in pathogenicity. The membrane and whole-cell proteins of both strains were similar; immunoblottting showed that the 35 kD and perhaps the 10 kD proteins were immunogens in both strains. Conclusion The major antigens of the two strains e and membrane proteins, as shown by comparing preparations. citing the host immune protein samples with response were the LPS reference and purified
文摘Objective To analyze the impact of depletion of the twin arginine translocation （TAT） system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity. Methods We constructed a △tatC：：Sp^R mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 △tatC：：Sp^R strain as a donor. Results A Pl-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type E enterocolitica strain and translocation of this enzyme was completely abolished by the △tatC：：Sp^R mutation. In addition, the △tatC：：Sp^R mutation showed a pleiotropic effect on the metabolism of E enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used. Conclusion Unlike other pathogenic bacteria studied, the TAT system of E enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O 157：H7.
基金Supported by the Science&Technology Department of Sichuan Province(2013FZ0014)the Construction Project of the Postgraduate Academic Degree in Southwest University for Nationalities(2013XWD-S071007)
文摘Yersinia enterocolitica is an important zoonotic pathogen that can induce disease outbreaks in a wide host range. Strain YER6022 was isolated from Pelteobagrus vachelli and identified using bacterial morphology and 16S rDNA sequence analysis. Five virulence factors were detected, then artificial infection experiment and histopathological method were carried out. These results showed that strain YER6022 was one of Y. enterocolitica family members. In addition, ail, ystb, virF, yadA and HPIint were dectected. In artificial infection experiment, with 80% mortality and 100% morbidity, injected Pelteobagrus vachellis showed red swollen of the anus, abdomen swelling and fim bleeding. There existed serious hyperaemia and edema in kidney, spleen, intestine and liver at the light microscope. Ultrastructural observation indicated that mitochondria of the liver, kidney, spleen and intestine swelled and mitochondrial cristae broke. The data had further shed light on its pathogenicity in Pelteobagrus vachelli. It would benefit for further studies on pathogenesis ofPelteobagrus vachelli infected with Y. enterocolitica.
文摘The public health significance of Yersinia spp. gives a new dimension to the prevailing food chain, wherein the foods do get exposed to heat and cold treatments. In this study, the effect of heat treatment on the native isolates of Yersinia enterocolitica CFR 2301 and Y. intermedia CFR 2303 revealed the D-values ranging from the lowest of 0.08 min at 65℃ in skim milk/beef gravy to the highest of 18.52 min at 50℃ in beef gravy. The heat sensitivity of both these cultures was in the order of Milli-Q water > 0.85% saline > skim milk > beef gravy. The z-values of the test cultures ranged from 7.55℃ for Y. intermedia to 12.08℃ for Y. enterocolitica. The heat sensitivity in Y. enterocolitica appeared to be related with growth incubation temperatures and also fatty acid profile of cell membrane. The effect of low temperature treatments (–20 ℃, 0℃ and 4℃ for 20 d) in water, saline and skim milk revealed the ability of Y. enterocolitica to survive more efficiently at –20℃, while Y. intermedia was more tolerant at 0℃. In packaged drinking water, Y. enterocolitica could survive and grow at 4℃ and 16℃, while at 30℃, inactivation was rapid. The findings did indicate that heat and cold treatments would not always ensure safety from Y. enterocolitica and Y. intermedia in the food chain.
文摘The purpose of this study was to evaluate the storage conditions as a way to increase the safety of fermented sausage, with the specific objectives to investigate the effect of storage time, pH value, water activity and microbiological status （Lactobacillus spp and Enterobacteriaceae） on the levels of Yersinia enterocolitica in fermented sausages. For this experiment, meat was divided into four equal portions of 10 kg each. The first portion was control group （C1 group） without addition of Y. enterocolitica and starter culture. The second portion （CII group） was inoculated starter, the third portion （EI group） was inoculated with I1. enterocolitica and the fourth portion （Eli group） was inoculated Y.. enterocolitica and starter culture. Sampling was performed by randomly selecting two links of each sausage preparation at the 0, 3rd, 6th, 9th, 15th, 25th and 35th day of drying. Results show that Y. enterocolitica and Enterobacteriaceae were not detected after 25 d of storage. The results indicate that practice utilizing starter culture is satisfactory to reduction of pathogen if present. Thus, inclusion with starter cultures in a maturation period may increase the safety of fermented sausages.
文摘In December 2017, two suspected outbreaks of <em>Yersinia enterocolitica </em>4/O:3 were notified in Finland. We analyzed the surveillance and outbreak investigation data and genotyped <em>Y. enterocolitica</em> strains in order to understand <em>Y. enterocolitica</em> epidemiology in Finland and to find out whether the notified outbreaks were related. A total of 13,344 <em>Y. enterocolitica</em> cases were reported in 1995-2018 to the National Infectious Diseases Register. The mean annual incidence ranged from 7.9 to 15.9/100,000 inhabitants. The highest incidence was observed in young adults (14/100,000). Incidence varied geographically. The incidence was higher in spring compared to other seasons. The most common pathogenic bioserotype was 4/O:3 but the information on bio/serotype was missing in 64% of the surveillance cases. For most of the cases, 87%, no travel history was reported. In the YE 4/O:3 outbreak investigation, whole genome sequencing was performed for isolates from 29/69 (42%) of the outbreak cases. The sequencing results showed that cases consisted of six independent clusters with 2 - 6 isolates in each cluster, and 5 sporadic isolates. No food item was found to be common to all of the clusters. In order to improve monitoring and facilitate the detection and investigation of<em> Y. enterocolitica</em> outbreaks, more comprehensive information on bio/serotype and on travel history is required in the surveillance.
基金supported by the Turku University Hospital and the Anne and Rauno Puolimatka Foundation.
文摘Prosthetic joint infection is a rare manifestation of Yersinia enterocolitica. We report a case of a patient presenting with fever and a purulent infection in his prosthetic knee joint caused by Y. enterocolitica. He had been operated in 1990 for arthrosis of the right knee. Re-operation was performed in 2007 for loosening of the prosthesis. Seven months later, following progressively increasing knee pain, he became acutely febrile and a purulent knee joint infection was diagnosed. Y. enterocolitica was isolated from the joint fluid. Serum antibodies against Y. enterocolitica were also positive. He was treated with debridement, replacement of the liner component of the prosthesis and a long course of intravenous antimicrobial therapy. The infection was thought to be in a chronic suppressive state. The final outcome after all therapy was good.
文摘Background Yersinia enterocolitica has been sporadically recovered from animals,foods,and human clinical samples in various regions of Ningxia,China.However,the ecological and molecular characteristics of Y.enterocolitica,as well as public health concerns about infection in the Ningxia Hui Autonomous Region,remain unclear.This study aims to analyze the ecological and molecular epidemiological characteristics of Y.enterocolitis in order to inform the public health intervention strategies for the contains of related diseases.Methods A total of 270 samples were collected for isolation[animals(n=208),food(n=49),and patients(n=13)],then suspect colonies were isolated and identified by the API20E biochemical identification system,serological tests,biotyping tests,and 16S rRNA-PCR.Then,we used an ecological epidemiological approach combined with machine learning algorithms(general linear model,random forest model,and eXtreme Gradient Boosting)to explore the associations between ecological factors and the pathogenicity of Y.enterocolitis.Furthermore,average nucleotide identity(ANI)estimation,single nucleotide polymorphism(SNP),and core gene multilocus sequence typing(cgMLST)were applied to characterize the molecular profile of isolates based on whole genome sequencing.The statistical test used single-factor analysis,Chi-square tests,t-tests/ANOVA-tests,Wilcoxon rank-sum tests,and Kruskal–Wallis tests.Results A total of 270 isolates of Yersinia were identified from poultry and livestock(n=191),food(n=49),diarrhoea patients(n=13),rats(n=15),and hamsters(n=2).The detection rates of samples from different hosts were statistically different(χ^(2)=22.636,P<0.001).According to the relatedness clustering results,270 isolates were divided into 12 species,and Y.enterocolitica(n=187)is a predominated species.Pathogenic isolates made up 52.4%(98/187),while non-pathogenic isolates made up 47.6%(89/187).Temperature and precipitation were strongly associated with the pathogenicity of the isolates(P<0.001).The random forest(RF)prediction model showed the best performance.The prediction result shows a high risk of pathogenicity Y.enterocolitica was located in the northern,northwestern,and southern of the Ningxia Hui Autonomous Region.The Y.enterocolitica isolates were classified into 54 sequence types(STs)and 125 cgMLST types(CTs),with 4/O:3 being the dominant bioserotype in Ningxia.The dominant STs and dominant CTs of pathogenic isolates in Ningxia were ST429 and HC100_2571,respectively.Conclusions The data indicated geographical variations in the distribution of STs and CTs of Y.enterocolitica isolates in Ningxia.Our work offered the first evidence that the pathogenicity of isolates was directly related to fluctuations in temperature and precipitation of the environment.CgMLST typing strategies showed that the isolates were transmitted to the population via pigs and food.Therefore,strengthening health surveillance on pig farms in high-risk areas and focusing on testing food of pig origin are optional strategies to prevent disease outbreaks.
