Objective: To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows. Methods: The milk sample was collected from a cow with mastitis, which was pretreated with 4% NaOH and inoculated with L-J medium for Mycobacterium isolation. The positive cultures were initially identified by acid-fast staining and multi-loci PCR, then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA, hsp65, ITS and SodA genes. The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay. Results: Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis, which were identified as non-tuberculosis mycobacterium by multi-loci PCR, and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis. The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics, including rifampicin and isoniazid, but they were sensitive to amikacin, moxifloxacin, levofloxacin, ethambutol, streptomycin, tobramycin, ciprofloxacin and linezolid. Conclusions:Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique. The results of the study can be used as reference for the prevention and control the infection in cows.
目的： 对疑似分枝杆菌感染乳腺炎奶牛进行病原及药敏谱调查。 方法： 采集1头患乳腺炎奶牛的牛奶，采用4% NaOH预处理，接种于L-J培养基分离培养。阳性培养物利用抗酸染色和多位点PCR方法进行初步鉴定，采用16S rRNA、hsp65、ITS和SodA基因的多位点序列分析进行种的鉴定，利用Alamar blue显色法对分离菌株进行27种药物的药敏试验。 结果： 从1头患乳腺炎奶牛的牛奶中同时分离获得2株抗酸染色阳性培养物，经PCR鉴定为非结核分枝杆菌，多位点序列分析鉴定为抗热分枝杆菌和象分枝杆菌。药敏试验表明这2株菌对利福平和异烟肼等大多数抗结核药物耐药，但对阿米卡星、莫西沙星、左氧氟沙星、乙胺丁醇、链霉素、妥布霉素、环丙沙星和利奈唑胺等敏感。 结论： 乳腺炎奶牛中分离了抗热分枝杆菌和象分枝杆菌，有其独特的药敏谱特征，为其感染防治提供了科学依据。.
Keywords: Cow with mastitis; Mycobacterium elephantis; Mycobacterium thermoresistibile; Non-tuberculosis mycobacterium.