广州市非结核分枝杆菌临床分离株菌种鉴定及药物敏感性试验结果分析

目的 对广州市非结核分枝杆菌(NTM)临床分离株进行菌种鉴定与药物敏感性试验(简称“药敏试验”),为临床诊断和治疗NTM病提供依据。方法从2016年广州市胸科医院行分枝杆菌分离培养的1250份标本中搜集培养阳性的717株临床分离株,采用水溶性对硝基苯甲酸(PNB)和噻吩-2-羧酸肼(TCH)对其进行培养,以鉴别MTB与NTM,通过多靶位基因聚合酶链反应 (PCR)测序,对PNB和TCH培养确定为NTM的菌株进一步行菌种鉴定,并采用最低抑菌浓度法(MIC)检测98株NTM对18种抗结核药物的耐药性。结果717株分枝杆菌中,检出106株NTM菌株,检出率为14.4%;其中103株传代成功,传代率为97.2%(103/106)。经NTM菌种鉴定,按照构成比高低依次为脓肿分枝杆菌34.0%(35/103)]、胞内分枝杆菌25.2%(26/103)]、马赛分枝杆菌20.4%(21/103)]、鸟分枝杆菌9.7%(10/103)]、堪萨斯分枝杆菌5.8%(6/103)]、偶发分枝杆菌1.9%(2/103)],以及1株缓黄分枝杆菌、1株猪分枝杆菌和1株阿加普尔分枝杆菌均占0.9%(1/103)]。98株NTM菌株的药敏试验结果显示,敏感者前3位依次为阿米卡星93.9%(92/98)]、克拉霉素91.8%(90/98)]和阿奇霉素71.4%(70/98)],耐药者前3位依次为利福平89.8%(88/98)]、左氧氟沙星83.7%(82/98)]和亚胺培南77.6%(76/98)]。并且NTM不同菌种对部分药物的耐药性存在种间差异。结论广州市NTM的检出率高于我国其他地区,流行的菌种以脓肿分枝杆菌和胞内分枝杆菌为主;克拉霉素和阿米卡星是临床治疗NTM患者的优选抗生素,应重视对利福平和左氧氟沙星的耐药性。

Analysis of strains identification and drug susceptibility characteristics of non-tuberculous mycobacterium isolated in Guangzhou

Objective To evaluate the species of non-tuberculous mycobacterium (NTM) isolated from Guangzhou Chest Hospital and perform drug susceptibility testing on these strains, to provide scientific basis for the diagnosis and treatment of NTM disease. Methods In 2016, 717 clinical mycobacterium isolates were collected from Guangzhou Chest Hospital, obtained from 1250 sputum species. All isolates were subjected to pnitrobenzoic acid (PNB) and 2 thiophene carborylic acid hydrazide (TCH) testing to distinguish Mycobacterium tuberculosis (MTB) from NTM. Then multi-locus polymerase chain reaction sequencing analysis was carried out to identify the NTM strains (confirmed by PNB and TCH) to species level. Furthermore, microporous plate method contained 18 antimicrobials was conducted to confirm the minimal inhibitory concentrations (MICs) of different NTM species. Results Among the 717 clinical mycobacterium isolates, 106 (14.4%, 106/717) NTM isolates were confirmed, and 103 isolates were available. According to the species identification assay, the most frequently isolated NTM species was Mycobacterium abscessus (34.0%, 35/103), followed by Mycobacterium intracellulare (25.2%, 26/103), Mycobacterium massiliense (20.4%, 21/103), Mycobacterium avium (9.7%, 10/103), Mycobacterium Kansasii (5.8%, 6/103), Mycobacterium fortuitum (1.9%, 2/103), Mycobacterium flavobacteriae (0.9%, 1/103), Mycobacterium porcine (0.9%, 1/103) and Mycobacterium acapulcensis (0.9%, 1/103) in Guangzhou. According to the drug susceptibility testing results of 98 NTM strains, amikacin (93.9%, 92/98), clarithromycin (91.8%, 90/98) and azithromycin (71.4%, 70/98) were the three most effective agents for NTM infection. However,rifampicin (89.8%,88/98), levofloxacin (83.7%,82/98) and imipenem (77.6%,76/98) were the most resistant drugs to NTM. Furthermore, the different drug susceptibility profiles of different NTM species was also characterized. Conclusion The NTM incidence in Guangzhou is much higher than other regions in China, Mycobacterium abscessus and Mycobacterium intracellular are the two most prevalent NTM species. Clarithromycin and amikacin are the preferred antimicrobials for treatment of NTM disease, doctors should pay more attention to the resistante of rifampicin and levofloxacin in clinical.