Otchere Isaac Darko, Asante-Poku Adwoa, Osei-Wusu Stephen, Aboagye Samuel Yaw, Yeboah-Manu Dorothy
Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of , Accra, Ghana.
Int J Mycobacteriol. 2017 Jan-Mar;6(1):70-75. doi: 10.4103/2212-5531.201895.
OBJECTIVE/BACKGROUND: Nontuberculous mycobacterial (NTM) species are assuming public health importance in pulmonary diseases; they are increasingly being isolated, and importantly, most NTMs do not respond to routine tuberculosis (TB) drugs. This study aimed to identify NTMs isolated from pulmonary TB cases and also determine their susceptibility to streptomycin (STR), isoniazid (INH), and rifampicin (RIF).
A total of 1755 mycobacterial isolates, obtained between August 2012 and July 2014, from 2036 smear-positive pulmonary cases were identified using polymerase chain reaction amplification of IS6110, and hsp65 gene sequencing analysis. Drug susceptibility testing (DST) was then performed for the identified NTMs against STR, INH, and RIF using microplate Alamar blue assay. The results were analyzed against patients' biodata for statistical associations.
Of the 1755 analyzed isolates, we identified 43 (2.5%) NTMs, which included 18 (41.9%) Mycobacterium intracellulare, 13 (30.2%) Mycobacterium avium subs. paratuberculosis, 5 (11.3%) Mycobacterium abscessus, 3 (7.0%) each of Mycobacterium mucogenicum and Mycobacterium colombiense, and 1 (2.3%) Mycobacterium simiae. Patients infected with NTMs (52.0%) were more likely to be human immunodeficiency virus-positive (P = 0.001, odds ratio = 6.6, 95% confidence interval = 2.7-16.2) than those infected with M. tuberculosis complex (5.8%). All the 43 (100%) NTMs were resistant to INH, whereas 32 (74%) and 19 (44%) were resistant to RIF and STR, respectively. Furthermore, 16 (37.2%) NTMs were resistant to all three drugs, 20 were resistant to INH and RIF, and 3 were resistant to STR and INH. All the M. abscessus isolates were resistant to all the three drugs, whereas all the M. avium isolates were resistant to INH and RIF, but only three were resistant to STR. Among the M. intracellulare isolates, 8, 18, and 15 isolates were resistant to STR, INH, and RIF, respectively.
The observed high-resistance level to INH and RIF supports the need for rapid species identification and DST of nonresponding TB cases before retreatment.
目的/背景：非结核分枝杆菌（NTM）菌种在肺部疾病中日益具有公共卫生重要性；它们的分离率越来越高，而且重要的是，大多数NTM对常规结核病（TB）药物无反应。本研究旨在鉴定从肺结核病例中分离出的NTM，并确定它们对链霉素（STR）、异烟肼（INH）和利福平（RIF）的敏感性。
2012年8月至2014年7月间，从2036例涂片阳性肺结核病例中获得了1755株分枝杆菌分离株，采用IS6110聚合酶链反应扩增和hsp65基因测序分析进行鉴定。然后使用微孔板阿拉玛蓝法对鉴定出的NTM进行针对STR、INH和RIF的药物敏感性试验（DST）。针对患者的生物数据对结果进行分析以寻找统计学关联。
在1755株分析的分离株中，我们鉴定出43株（2.5%）NTM，其中包括18株（41.9%）胞内分枝杆菌、13株（30.2%）副结核分枝杆菌鸟分枝杆菌亚种、5株（11.3%）脓肿分枝杆菌、黏液分枝杆菌和哥伦比亚分枝杆菌各3株（7.0%）以及1株（2.3%）猿分枝杆菌。感染NTM的患者（52.0%）比感染结核分枝杆菌复合群的患者（5.8%）更有可能是人类免疫缺陷病毒阳性（P = 0.001，比值比 = 6.6，95%置信区间 = 2.7 - 16.2）。所有43株（100%）NTM对INH耐药，而分别有32株（74%）和19株（44%）对RIF和STR耐药。此外，16株（37.2%）NTM对这三种药物均耐药，20株对INH和RIF耐药，3株对STR和INH耐药。所有脓肿分枝杆菌分离株对这三种药物均耐药，而所有鸟分枝杆菌分离株对INH和RIF耐药，但只有3株对STR耐药。在胞内分枝杆菌分离株中，分别有8株、18株和15株对STR、INH和RIF耐药。
观察到的对INH和RIF高耐药水平支持在复治前对无反应的结核病例进行快速菌种鉴定和DST的必要性。
