Different animals in Xinjiang carry Escherichia coli O157:H7(E.coli O157:H7),but the connection between these strains is not clear.This study aims to understand the evolutionary sub-group of E.coli O157:H7,the distribution of the dominant genetic lineage,the biofilm formation ability,the carriage of mobile genetic elements and their drug resistance profile.E.coli O157:H7 was identified by PCR.Multilocus sequence typing(MLST)protocol was used for E.coli O157 to detect ST type,plasmid replicon and integron genes.Biofilm formation ability was determined by crystal violet microplate,and Kirby-Bauer was used to detect drug resistance.The results showed that 46.7％(7/15)of E.coli O157:H7 belongs to Group A,53.3％(8/15)of E.coli O157:H7 be-longs to Group E.Sheep source were mainly prevalent in Group A(4/6).Cattle sources are mainly Group E(6/7).A total of six ST types were detected:ST11(8/15),ST-206(1/15),ST-6126(3/15),ST-1640(1/15),ST-178(1/15),ST-4550(1/15).Two strains had a moderate biofilm-form-ing capacity,two strains had a weak biofilm-forming capacity,10 strains have no biofilm-forming capacity.All were multidrug-resistant strains,with complete resistance to lincomycin,oxacillin,clindamycin,vancomycin,midemycin and cefthiophene,and 88％-94％resistance to poly-myxin B,ampicillin,penicillin G and erythromycin,they are highly drug resistant.The five resist-ance genes detected were acrA(66.66％,10/15),tolC(73.33％,11/15),qurS(13.33％,2/15),floR and qurA(6.67％,1/15).Four plasm id replicons were detected,they were IncP(66.66％,10/15),IncFrepB(86.67％,13/15),IncFIA(6.67％,1/15),IncFIB(66.66％,10/15).Two class Ⅰ integrons were detected and they were ISCR1(33.33％,5/15),ISECP1(20％,3/15).The re-sults showed that E.coli O157:H7 in Xinjiang was predominantly prevalent in Group A and Group E.Sheep sources were predominantly prevalent in Group A,and cattle sources were predominantly prevalent in Group E.The ST types were widely distributed,with ST11 types being the predomi-nant type,the biofilm-forming ability was weak,and the resistance was strong,all of them were multi-drug-resistant strains,and the resistance genes were mainly externally excreted from the pumps,and the resistance genes had more spreading elements.

Different animals in Xinjiang carry Escherichia coli O157:H7(E.coli O157:H7),but the connection between these strains is not clear.This study aims to understand the evolutionary sub-group of E.coli O157:H7,the distribution of the dominant genetic lineage,the biofilm formation ability,the carriage of mobile genetic elements and their drug resistance profile.E.coli O157:H7 was identified by PCR.Multilocus sequence typing(MLST)protocol was used for E.coli O157 to detect ST type,plasmid replicon and integron genes.Biofilm formation ability was determined by crystal violet microplate,and Kirby-Bauer was used to detect drug resistance.The results showed that 46.7％(7/15)of E.coli O157:H7 belongs to Group A,53.3％(8/15)of E.coli O157:H7 be-longs to Group E.Sheep source were mainly prevalent in Group A(4/6).Cattle sources are mainly Group E(6/7).A total of six ST types were detected:ST11(8/15),ST-206(1/15),ST-6126(3/15),ST-1640(1/15),ST-178(1/15),ST-4550(1/15).Two strains had a moderate biofilm-form-ing capacity,two strains had a weak biofilm-forming capacity,10 strains have no biofilm-forming capacity.All were multidrug-resistant strains,with complete resistance to lincomycin,oxacillin,clindamycin,vancomycin,midemycin and cefthiophene,and 88％-94％resistance to poly-myxin B,ampicillin,penicillin G and erythromycin,they are highly drug resistant.The five resist-ance genes detected were acrA(66.66％,10/15),tolC(73.33％,11/15),qurS(13.33％,2/15),floR and qurA(6.67％,1/15).Four plasm id replicons were detected,they were IncP(66.66％,10/15),IncFrepB(86.67％,13/15),IncFIA(6.67％,1/15),IncFIB(66.66％,10/15).Two class Ⅰ integrons were detected and they were ISCR1(33.33％,5/15),ISECP1(20％,3/15).The re-sults showed that E.coli O157:H7 in Xinjiang was predominantly prevalent in Group A and Group E.Sheep sources were predominantly prevalent in Group A,and cattle sources were predominantly prevalent in Group E.The ST types were widely distributed,with ST11 types being the predomi-nant type,the biofilm-forming ability was weak,and the resistance was strong,all of them were multi-drug-resistant strains,and the resistance genes were mainly externally excreted from the pumps,and the resistance genes had more spreading elements.

In order to understand the infection and molecular genetic characteristics of goose astro-virus(GAstV)in Hotan,Xinjiang,visceral organs and swabs of dead goslings were collected asep-tically from three goose farms in Hotan,Yutian and Pashan counties,and GAstV was detected by RT-PCR.The positive samples were screened and identified in LMH cells,and the whole genome was sequenced,and the genetic characteristics of the isolates were analyzed.The results showed that the total positive rate of GAstV was 11.25％(65/578).Two strains of GAstV named as GAstV/XJHT-1 and GAstV/XJHT-2 were isolated and the lengths of their genome sequences were determined as 7 190 bp and 7 125 bp,respectively.Whole genome homology analysis showed that the homology of the two isolates with GAstV-1 and GAstV-2 was higher than 95％,and the homology with other sources(chicken,duck,and turkey)ranged from 54.1％to 61.5％.Genetic e-volution analysis showed that the genetic distance between GAstV isolates from Henan and Anhui was relatively close,suggesting that the isolated GAstV may be related to the introduction of gos-lings or goose eggs from these two places.The findings provide a basis for further development of vaccines or control products.

Klebsiella pneumoniae(KPn),as a conditioned pathogen that causes calf pneumonia,has caused serious harm to cattle industry,but the harm of Klebsiella pneumoniae to calves in Xin-jiang region is still unclear.In this study,to investigate the prevalence of KPn,its harm and some biological characteristics of pneumonia calves in Xinjiang,nasal swabs of pneumonia calves in some areas were collected aseptically,KPn isolation and identification were performed by routine meth-od,and 16S rDNA sequence evolutionary tree analysis was performed.The drug resistance was de-tected by K-B method,and a strain carrying multiple virulence was selected for mice median lethal dose test.The serotype,virulence gene and drug resistance gene of the strain were detected by PCR.The results showed that the detection rate of Klebsiella pneumoniae in nasal swabs of 218 pneumonia calves from Aksu,Changji and Yili regions of Xinjiang was as follows:14.68％(32/218),including 28.33％(17/60)in Aksu Prefecture,24.00％(6/25)in Changji Prefecture and 6.77％(9/133)in Yili Prefecture,they were divided into two serotypes,namely K1(7/32)and K5(5/32).A total of 13 KPn virulence genes were detected,mainly mrkD,ureA,wabG,uge and en-tB.LD50 was 2.38X 107cfu/mL.Drug susceptibility test and drug resistance gene detection showed that the isolated strain showed multiple drug resistance,and the resistance genes mainly carried blasHv and floR.16S rDNA sequence evolutionary tree results showed that the isolated strain had high homology with the isolates from Italy,Beijing and Shanghai of China.The detection rate of KPn in nasal swabs of pneumonia calves in Xinjiang region is high.The dominant serotypes are K1 and K5.The isolates carry a variety of virulence genes and have strong virulence.All of them are KPn strains producing ESBLs,suggesting that Klebsiella pneumoniae in Xinjiang region of China have a certain potential harm to calves.