Epidemiological Investigation,pathogen Isolation And Identification,and Drug Resistance Gene Detection Of Bovine Mycoplasma Disease In Intensive Cattle Farms In Southern Xinjiang

Mycoplasma bovis infection in cattle can cause a variety of clinical diseases,including respiratory diseases,mastitis,arthritis,and otitis media.These diseases affect the health of cattle and cause serious losses to the cattle industry.In order to understand the prevalence of bovine mycoplasma disease and the characteristics of epidemic strains in southern Xinjiang,this study collected cow blood and nasal swabs from11 intensive dairy farms in the region from December 2021 to March 2022.Through seroepidemiological and molecular epidemiological investigations on the samples,as well as the isolation and identification of the pathogen,morphological observation,biochemical identification,PCR detection,and drug resistance gene detection were conducted on the isolated strains.The test results show that:1.After testing 498 serum samples,126 positive samples were detected using the ELISA kit for Mycoplasma bovis antibodies,with a detection rate of 25.30%(126/498).The highest positive rates were found in Field A and Field D,both of which were 50.00%(25/50);Among the 11 intensive aquaculture farms,8 farms with positive antibodies had an epidemiological history of respiratory diseases within five years,with a population positive rate of 72.73%(8/11).2.41 collected bovine nose swabs were subjected to universal PCR detection of Mycoplasma 16 S r RNA and bovine Mycoplasma opp F gene specific PCR detection.The total positive rate of universal primer PCR detection was 39.02%(16/34).The sequencing test results showed that the detection rate of Mycoplasma bovis was 43.75%(7/16),and the detection rates of Mycoplasma bovirhinis,Mycoplasma arginini,and Mycoplasma dispar were all 18.75%(3/16);The results of opp F primer PCR retest are the same as those of universal primer detection;Two types of Mycoplasma were detected simultaneously in one field,and the higher detection rate was the combination of Mycoplasma bovis and Mycoplasma dispar.3.A total of 6 isolates were obtained from 16 positive nasal swab samples,including 4 isolates of Mycoplasma bovis and 2 isolates of Mycoplasma dispar.Through morphological observation and biochemical identification,they all conformed to the typical characteristics of Mycoplasma;The 16 S r RNA sequencing results showed that the isolates had a similarity of over 97% with multiple Mycoplasma bovis strains from Gen Bank;Seven types of 22 drug resistance genes were detected in the isolated strains,and a total of 4 drug resistance genes were detected: TEM,gyr A,par C,and tet C.The highest proportio n of multidrug resistance genes is 4,and the lowest proportion is 3.Conclusion: After research,it was found that the positive rate of serum epidemiology in this study is higher than the relevant reports in the southern Xinjiang region from 2018 to 2021,showing an upward trend.All six isolated strains have resistance genes to three common types of antibiotics,indicating that the prevalent strains in the area have certain resistance.This study provides reference data for the prevention,control,and diagnosis of bovine mycoplasma in Aksu,Bazhou,and Kashgar regions of Xinjiang.