牛支原体的分离鉴定及中药体外抗菌作用OA

To investigate the distribution and antimicrobial resistance of Mycoplasma bovis in different regions of China and to preliminarily screen effective traditional Chinese medicines against Mycoplasma bovis,a total of 84 samples were collected in November 2023 from cattle suspected of Mycoplasma bovis infection with respiratory diseases(nasal swabs)and lung tissues from dead cattle across seven regions,including Anhui,Inner Mongolia,and Yunnan.Pathogen isolation and culture were conducted,and the isolates were identified based on colony and cell morphology,specific gene(oppD/F,uvrC)amplification,and 16S rRNA gene sequence analysis.In vitro antimicrobial susceptibility tests were performed to evaluate the effects of eight antibiotics and ten traditional Chinese medicines water decoctions against the isolates.The results showed that 27 of the 84 samples were Mycoplasma bovis positive,and four isolates,designated Mb1-Mb4,were obtained.On pleuropneumonia like organism broth(PPLO)solid medium,the isolates formed pinhead-sized white colonies that appeared blue after Dienes staining;scanning electron microscopy revealed spherical cells.PCR amplification of oppD/F,uvrC,and 16S rRNA genes yielded the expected bands specific to Mycoplasma bovis,and 16S rRNA sequences showed>99.7%similarity with reference Mycoplasma bovis sequences in NCBI.Antimicrobial susceptibility tests demonstrated that all four isolates were multidrug-resistant,showing varying degrees of resistance to seven antibiotics.Among the tested traditional Chinese medicines,Coptis chinensis(Huanglian),Schisandra chinensis(Wuweizi),Syzygium aromaticum(Clove),and Scutellaria baicalensis(Huangqin)exhibited strong antibacterial activity against all isolates,with minimum inhibitory concentration(MIC)values of 7.81,15.63,31.25,and 62.50 mg/mL,respectively.These results indicate that Mycoplasma bovis is prevalent in large-scale cattle farms across multiple regions of China,with isolates showing severe antimicrobial resistance.Coptis chinensis,Schisandra chinensis,Syzygium aromaticum,and Scutellaria baicalensis demonstrated good antibacterial potential against Mycoplasma bovis and may serve as promising traditional Chinese medicinal candidates for further investigation.This study investigated the distribution and antimicrobial resistance of Mycoplasma bovis in multiple regions of China and confirmed the antibacterial potential of traditional Chinese medicines against this pathogen,providing a theoretical basis for the development of related Chinese herbal compound formulations and novel preparations.