脓肿分枝杆菌16S rRNA检测及生物学特性研究

目的 鉴定1株脓肿分枝杆菌临床分离株。方法 取2017年12月18日就诊于潍坊医学院附属医院的1例疑似非结核分枝杆菌感染患者的脓液标本行细菌培养、革兰染色和抗酸染色；药敏试验采用比例法。提取菌株基因组DNA，选用16S rRNA通用引物进行PCR扩增，回收、纯化产物后测序，与GenBank数据库中已知脓肿分枝杆菌序列比较同源性。采用基质辅助激光解吸电离飞行时间质谱鉴定分离株。结果 基质辅助激光解吸电离飞行时间质谱与16S rRNA基因检测均鉴定该分离菌为脓肿分枝杆菌。药敏试验显示该菌对阿米卡星、莫西沙星、左氧氟沙星敏感，对链霉素、异烟肼、利福平、乙胺丁醇、氧氟沙星、卡那霉素、卷曲霉素、对氨基水杨酸、丙硫异烟胺、利福布汀耐药。诊断为左膝关节皮下软组织感染。根据药敏试验结果，给予阿米卡星和左氧氟沙星治疗后，症状好转。结论 16S rRNA检测与基质辅助激光解吸电离飞行时间质谱可用于脓肿分枝杆菌鉴定。

Detection of 16S rRNA gene and biological characteristics of Mycobacterium abscessus

Sun Mingyan, Wu Qianqian, Wang Yexin, Wang Nan, Liu Yanxia, Tao YuanyongClinical Laboratory, Affiliated Hospital of Weifang Medical University, Shandong 261031, China （Sun MY, Wu QQ, Wang N, Liu YX, Tao YY）; Department of Joint Surgery, Affiliated Hospital of Weifang Medical University, Shandong 261031, China （Wang YX）Corresponding author: Tao Yuanyong, Email: taoyuanyong@163.com【Abstract】 Objective To identify a clinical isolate of Mycobacterium abscessus. Methods A pus sample was collected from a patient with suspected nontuberculous mycobacterial infection who visited the Affiliated Hospital of Weifang Medical University on December 18, 2017, and was subjected to bacterial culture, Gram staining and acid-fast staining. Drug sensitivity test was conducted by the proportion method. The genome DNA of the strain was extracted and amplified by PCR with the universal primer of 16S rRNA. The PCR products were sequenced after collection and purification, and were compared with the known sequence of Mycobacterium abscessus in GenBank database. The isolate was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS）. Results The clinical isolate was identified as Mycobacterium abscessus both by MALDI-TOF MS and 16S rRNA gene sequencing. The drug sensitivity test showed that the strain was sensitive to amikacin, moxifloxacin, levofloxacin, but was resistant to streptomycin, isoniazid, rifampicin, ethambutol, ofloxacin, kanamycin, capreomycin, aminosalicylic acid, protionamide and rifabutin. The patient was diagnosed with subcutaneous soft tissue infection in the left knee joint. According to the results of drug sensitivity test, the patient was treated with amikacin and levofloxacin, and her condition was improved after treatment. Conclusion The 16S rRNA gene detection and MALDI-TOF MS both can be applied in the identification of Mycobacterium abscessus.