This study aims to understand the epidemic distribution characteristics,antimicrobial resistance,virulence genes,and biofilm adhesion ability of Enterococcus in yaks on the Tibetan plateau.Three hundred and forty-six fresh yak fecal samples and 311 milk samples were collected from four provinces on the Tibetan plateau(Xizang,Sichuan,Gansu,Qinghai),totaling 657 sam-ples.Bacterial isolation and identification were conducted,followed by 16S rDNA gene detection and the construction of a systematic evolutionary tree.The isolated strains were tested for antimi-crobial resistance and virulence genes using PCR,and sensitivity tests were performed using 18 types of antibiotics.The biofilm adhesion ability of the isolated bacteria was determined using an improved semi-quantitative crystal violet staining method.The results showed that the total isola-tion rate of Enterococcus was 32.27％,with Sichuan having the highest at 60.23％,followed by Gansu,Qinghai,and Tibet autonomous region at 42.70％,23.47％,and 18.31％respectively.In terms of sample types,the isolation rate in fecal samples was 36.71％,and in milk samples,it was 27.33％.Through PCR amplification,bands of approximately 1 400 bp were obtained,and 5 strains were selected for evolutionary analysis,forming a separate cluster.Among the 212 isolated strains,a high resistance to clindamycin,quinupristin-dalfopristin,linezolid,levofloxacin,and erythromycin was observed,with various resistance phenomena,accounting for 60.85％.Only 5 out of 12 resist-ant genes were detected,namely erm(B),tet(L),tet(O),tet(M),and ant(6)-Ia.All 13 virulence genes were detected in Enterococcus,with detection rates in the range of 5.19％to 95.76％,where cpd was 95.75％,gelE was 91.98％,efaA was 86.79％,asal was 86.32％,and the rest ranged from 5.19％to 55.66％.The fsr virulence gene was not detected in Enterococcus from milk sources.Among the isolated strains,3.30％showed medium adhesive ability,48.58％showed weak adhesive ability,and 48.11％showed no adhesive ability.The above research revealed the preva-lence of yak derived Enterococcus,the carrying status of resistance and virulence genes,and the correlation between biofilm phenotypes,laying the foundation for mastering research data on yak-derived Enterococcus in the Tibetan plateau.

To understand the epidemiological characteristics and antimicrobial resistance of Esche-richia coli in free-range Tibetan pig populations,fecal samples from these pigs were collected be-tween 2021 and 2023 for pathogen isolation and identification.The isolated strains underwent anal-ysis of pathogenicity categories,phylogenetic grouping,and antimicrobial susceptibility profiles,a-long with resistance gene detection and mouse pathogenicity testing.The results showed that 123 strains of E.coli were isolated from 132 fecal samples.Enteropathogenicity tests revealed that 42.28％were EAEC(52/123),7.32％were EPEC(9/123),and 3.25％were STEC/EHEC(4/123).Phylogenetic analysis indicated that 78.86％(97/123)belonged to group A,while 11.38％(14/123)belonged to group B1.Antimicrobial susceptibility tests for 22 drugs showed the highest resistance rate to amoxicillin at 98.37％(121/123),followed by sulfamethoxazole at 73.98％(91/123).Resistance rates for ampicillin,tetracycline,erythromycin,and trimethoprim ranged from 48.78％to 51.22％.Furthermore,78.86％(97/123)of the isolates were resistant to three or more antibiotics.The detection of 52 drug-resistance genes in 10 categories showed that 15 drug-resist-ance genes were detected,and the detection rate was 28.85％(15/52).Among individual resistance genes,tetA had the highest detection rate at 63.41％(78/123),followed by tetB and qnrS with de-tection rates of 48.78％(60/123)and 38.21％(47/123),respectively.This study demonstrates that EAEC is the predominant strain of E.coli in free-range Tibetan pigs,with groups A and B1 being the major phylogenetic groups.The isolates exhibited a high degree of multidrug-resistant pheno-types,and the detection rates of resistance genes were also high.E.coli carrying virulence genes cause different degrees of pathological changes in the mouse ileum.The research results have sig-nificant public health implications and provide theoretical basis for the prevention,treatment,and clinical medication of E.coli disease in Tibetan pigs.

To understand the epidemiological characteristics and antimicrobial resistance of Esche-richia coli in free-range Tibetan pig populations,fecal samples from these pigs were collected be-tween 2021 and 2023 for pathogen isolation and identification.The isolated strains underwent anal-ysis of pathogenicity categories,phylogenetic grouping,and antimicrobial susceptibility profiles,a-long with resistance gene detection and mouse pathogenicity testing.The results showed that 123 strains of E.coli were isolated from 132 fecal samples.Enteropathogenicity tests revealed that 42.28％were EAEC(52/123),7.32％were EPEC(9/123),and 3.25％were STEC/EHEC(4/123).Phylogenetic analysis indicated that 78.86％(97/123)belonged to group A,while 11.38％(14/123)belonged to group B1.Antimicrobial susceptibility tests for 22 drugs showed the highest resistance rate to amoxicillin at 98.37％(121/123),followed by sulfamethoxazole at 73.98％(91/123).Resistance rates for ampicillin,tetracycline,erythromycin,and trimethoprim ranged from 48.78％to 51.22％.Furthermore,78.86％(97/123)of the isolates were resistant to three or more antibiotics.The detection of 52 drug-resistance genes in 10 categories showed that 15 drug-resist-ance genes were detected,and the detection rate was 28.85％(15/52).Among individual resistance genes,tetA had the highest detection rate at 63.41％(78/123),followed by tetB and qnrS with de-tection rates of 48.78％(60/123)and 38.21％(47/123),respectively.This study demonstrates that EAEC is the predominant strain of E.coli in free-range Tibetan pigs,with groups A and B1 being the major phylogenetic groups.The isolates exhibited a high degree of multidrug-resistant pheno-types,and the detection rates of resistance genes were also high.E.coli carrying virulence genes cause different degrees of pathological changes in the mouse ileum.The research results have sig-nificant public health implications and provide theoretical basis for the prevention,treatment,and clinical medication of E.coli disease in Tibetan pigs.

This study aims to understand the epidemic distribution characteristics,antimicrobial resistance,virulence genes,and biofilm adhesion ability of Enterococcus in yaks on the Tibetan plateau.Three hundred and forty-six fresh yak fecal samples and 311 milk samples were collected from four provinces on the Tibetan plateau(Xizang,Sichuan,Gansu,Qinghai),totaling 657 sam-ples.Bacterial isolation and identification were conducted,followed by 16S rDNA gene detection and the construction of a systematic evolutionary tree.The isolated strains were tested for antimi-crobial resistance and virulence genes using PCR,and sensitivity tests were performed using 18 types of antibiotics.The biofilm adhesion ability of the isolated bacteria was determined using an improved semi-quantitative crystal violet staining method.The results showed that the total isola-tion rate of Enterococcus was 32.27％,with Sichuan having the highest at 60.23％,followed by Gansu,Qinghai,and Tibet autonomous region at 42.70％,23.47％,and 18.31％respectively.In terms of sample types,the isolation rate in fecal samples was 36.71％,and in milk samples,it was 27.33％.Through PCR amplification,bands of approximately 1 400 bp were obtained,and 5 strains were selected for evolutionary analysis,forming a separate cluster.Among the 212 isolated strains,a high resistance to clindamycin,quinupristin-dalfopristin,linezolid,levofloxacin,and erythromycin was observed,with various resistance phenomena,accounting for 60.85％.Only 5 out of 12 resist-ant genes were detected,namely erm(B),tet(L),tet(O),tet(M),and ant(6)-Ia.All 13 virulence genes were detected in Enterococcus,with detection rates in the range of 5.19％to 95.76％,where cpd was 95.75％,gelE was 91.98％,efaA was 86.79％,asal was 86.32％,and the rest ranged from 5.19％to 55.66％.The fsr virulence gene was not detected in Enterococcus from milk sources.Among the isolated strains,3.30％showed medium adhesive ability,48.58％showed weak adhesive ability,and 48.11％showed no adhesive ability.The above research revealed the preva-lence of yak derived Enterococcus,the carrying status of resistance and virulence genes,and the correlation between biofilm phenotypes,laying the foundation for mastering research data on yak-derived Enterococcus in the Tibetan plateau.

In order to understand the potential target and related mechanism of action of Termina-lia Chebula treatment,network pharmacology and molecular docking methods were used in this experiment,and the challenge test of Salmonella from yak was performed.The active ingredients and potential targets of Terminalia Chebula were screened through HERB cluster identification database,TCMSP database and SwissTargetPrediction web page tool,and"gastroenteritis"was searched through OMIM and GeneCards database.Cytoscape and STRING databases were used to construct the Terminalia Chebula PPI network to screen out key targets,the intersection targets between Terminalia Chebula and enteritis were obtained through Venny platform,and gene ontol-ogy(GO)and Kyoto encyclopedia database of genes and genomics(KEGG)were enriched through DAVID database.The core target of screening was verified by molecular docking.After that,the gastrointestinal inflammation model of mice was established,the pathological changes of gastroin-testinal tract were observed,and the effect of Terminalia Chebula on the target protein was veri-fied by Western blot test.The results showed that:after analyzing and sorting out 8 main active in-gredients of Terminalia Chebula,118 targets of Terminalia Chebula were screened,11 161 targets of gastroenteritis and 100 targets of intersection were obtained;the core targets of PTGS2,CASP3,SLC3A2,Bax,Bcl-2 and TP53 of Terminalia Chebula and enteritis were obtained through PPI network.GO and KEGG enrichment analysis collected 337 items and 138 items,respectively,mainly related to chemokine pathway,PI3K-Akt signaling pathway,apoptosis related pathway,i-ron ion transport related pathway,NF-κB signaling pathway,etc.The results of molecular docking showed that chebulidic acid,the first active component of chebulidic acid,can bind to Bax,Bcl-2,PTGS2 and SLC3A2 through hydrogen bonding,hydrophobic action,π-π packing force and other intermolecular forces.The pathological tissue sections showed that Terminalia Chebula could sig-nificantly recover gastrointestinal tissue injury.Western blot test results showed that Terminalia Chebula can regulate the process of apoptosis and iron death through Bax/Bcl-2 and PTGS2/SLC3A2 pathways to achieve the effect of treating intestinal inflammatory damage.The results showed that Terminalia Chebula can regulate the occurrence and development of enteritis by regu-lating apoptosis and iron death through Bax/Bcl-2 and PTGS2/SLC3A2 pathways.Terminalia Chebula has the characteristics of multi-target and multi-pathway in the treatment of enteritis.

The purpose of this study was to reveal the resistance mechanism of Mycoplasma bovis from Xizang yaks to macrolide antibiotics and provide theoretical basis for clinical medication.In this study,10 strains of Mycoplasma bovis from Xizang yaks were tested for drug sensitivity to macrolide antibiotics using the micromethod,and sensitive strains were induced to be highly resist-ant in vitro.The results showed that all 10 strains of Mycoplasma bovis exhibited varying degrees of resistance to macrolide antibiotics.However,through methylation enzyme and inactivation en-zyme gene detection and analysis,it was found that there was no methylation enzyme encoded by the methylation enzyme gene and no resistance mechanism mediated by macrolide inactivation en-zymes,indicating that there were no mutations in the target gene loci of the sensitive and resistant strains.However,highly resistant strains in vitro have mutations at the domain Ⅱ,L22,and even L4 target gene loci,indicating that if two or more target gene amino acid loci undergo mutations,highly resistant strains can be produced.After testing with active efflux systems,it was found that there were no active efflux systems using macrolide antibiotics as substrates.It can be seen that the strain of Mycoplasma bovis from Xizang yaks is prone to mutation under the pressure of high con-centrations of macrolides,and there are mutations in two or more target gene amino acid sites,which is prone to produce highly resistant strains.

This study aims to understand the Escherichia coli drug resistance isolated from different parts of Tibet yak in order to provide scientific evidence for controling Escherichia coli.PCR analysis of drug resistance phenotype and drug resistance gene of aminoglycosides,florfenicol and sulfonamides were carried out in 200 strains of yak-derived Escherichia coli from 6 different places in Tibet.The results showed that the resistance rate of aminoglycoside to yak-derived Escherichia coli was 96％ of amikacin,94.59％ of streptomycin,19％ of neomycin,23％ of gentamicin,19％ of kanamycin.The detection rate of rmtB gene was 100％.The drug resistance rate of florfenicol was 25％ with 25％ detection rate of resistance geneflor.The resistance rate of sulfonamides was 32％ with 7％,7％ and 17％ detection rates of sul1,sul2 and sul3 respectively genes,Moreover,the result of drug resistance phenotype was consistent with that of drug resistance gene.Meanwhile,the expression of sull gene in different regions of Tibet were different in drug resistance of the bacilli,and those from the population-intensive and flow-sensitive Lhasa,Nyingchi and Xigaze were more resistant to drug resistance,while those from Ali,Shannan and Nagqu were relatively light.The above-mentioned drug-resistant phenotype and drug resistance genes were detected in different cities and regions of Tibet,and there were multiple drug-resistant phenomena.The results showed that there was resistance to Escherichia coli in Tibetan yak,which should be paid attention to,and suggested that the in Tibetan area the antibiotics should be rationally used to reduce the drug resistance.

Toxocara vitulorum has been rarely reported in yaks at high altitudes and remote areas of Sichuan Province of Tibetan Plateau of China. The current study was designed to investigate the prevalence, associated risk factors, and phylogenetic characteristics of T. vitulorum in yak calves on the Qinghai Tibetan plateau. Fecal samples were collected from 891 yak calves and were examined for the presence of T. vitulorum eggs by the McMaster technique. A multivariable logistic regression model was employed to explore variables potentially associated with exposure to T. vitulorum infection. T. vitulorum specimens were collected from the feces of yaks in Hongyuan of Sichuan Province, China. DNA was extracted from ascaris. After PCR amplification, the sequencing of ND1 gene was carried out and phylogenetic analyses was performed by MEGA 6.0 software. The results showed that 64 (20.1%; 95% CI 15.8–24.9%), 75 (17.2; 13.8–21.1), 29 (40.9; 29.3–53.2), and 5 (7.6; 2.5–16.8) yak calves were detected out to excrete T. vitulorum eggs in yak calve feces in Qinghai, Tibet, Sichuan, and Gansu, respectively. The present study revealed that high infection and mortality by T. vitulorum is wildly spread on the Qinghai Tibetan plateau, China by fecal examination. Geographical origin, ages, and fecal consistencies are the risk factors associated with T. vitulorum prevalence by logistic regression analysis. Molecular detection and phylogenetic analysis of ND1 gene of T. vitulorum indicated that T. vitulorum in the yak calves on the Qinghai Tibetan plateau are homologous to preveiously studies reported.
Altitude ; Animals ; Ascaris ; Cattle* ; China* ; DNA ; Eggs ; Feces ; Logistic Models ; Mortality ; Ovum ; Polymerase Chain Reaction ; Prevalence* ; Risk Factors* ; Tibet ; Toxocara*