Department of Veterinary Medicine and Public Health, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania.
Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
PLoS One. 2022 Mar 24;17(3):e0265358. doi: 10.1371/journal.pone.0265358. eCollection 2022.
While most Non-tuberculous mycobacteria (NTM) are saprophytic, several species have been associated with human diseases, from localized infection to disseminated diseases. Pulmonary NTM infections lead to TB-like disease called NTM pulmonary disease (NTM-PD). Due to variation in treatment options among NTM species, it is necessary to identify the species and determine drug susceptibility profiles to inform the choice of appropriate regimen for the disease.
A total of 188 culture-positive isolates from patients diagnosed with TB were screened for NTM at the Central Tuberculosis Reference Laboratory. All NTM were further speciated using GenoType® Mycobacterium-Common Mycobacterium and Additional species (GenoType® CM/AS) kit. Mycobacteria avium complex (MAC) and Mycobacteria abscessus complex (MABC) which could not be identified with the test to species were subjected to GenoType® Mycobacteria NTM-DR for further speciation. Using the same test, identified MAC and MABC were genotyped to determine the drug susceptibility profile for each isolate to macrolide and aminoglycosides.
Of all isolates identified as mycobacteria, 24 (13%) were NTM. Fifteen isolates could be identified to species level of which prevalent species was M. avium sub. intracellulare 4 (27%). A total of 10 isolates were MAC (n = 6) and MABC (n = 4) were subjected to GenoType® Mycobacteria NTM-DR for determination of macrolide and aminoglycoside susceptibility. Three of the four MABC had a mutation at the T28 position of the erm (41). All MAC were susceptible to both drugs.
In this study, MAC was the most frequently isolated NTM species followed by MABC. While all MAC and MABC identified, were susceptible to aminoglycosides, three MABC were resistant to the macrolides due to mutation at position 28 of the erm (41) gene. For this, it is important for clinicians need to rule out NTM, understand species and their drug susceptibility for optimal case management.
虽然大多数非结核分枝杆菌（NTM）是腐生的，但有几种已与人类疾病相关，从局部感染到播散性疾病。肺部 NTM 感染导致类似于结核病的疾病，称为 NTM 肺部疾病（NTM-PD）。由于不同 NTM 物种的治疗选择存在差异，因此有必要确定物种并确定药物敏感性谱，以告知疾病适当治疗方案的选择。
在中央结核病参考实验室，对诊断为结核病的患者的 188 例培养阳性分离株进行 NTM 筛查。使用 GenoType®分枝杆菌-常见分枝杆菌和其他种属（GenoType® CM/AS）试剂盒进一步对所有 NTM 进行种属鉴定。无法通过该试验鉴定为种属的鸟分枝杆菌复合群（MAC）和脓肿分枝杆菌复合群（MABC），则进行 GenoType®分枝杆菌 NTM-DR 进一步鉴定。使用相同的试验，对鉴定的 MAC 和 MABC 进行基因分型，以确定每个分离株对大环内酯类和氨基糖苷类药物的药物敏感性谱。
在所有鉴定为分枝杆菌的分离株中，有 24 株（13%）为 NTM。15 株可鉴定至种属水平，其中最常见的种属是鸟分枝杆菌亚种细胞内 4 株（27%）。共有 10 株为 MAC（n=6），4 株为 MABC，进行 GenoType®分枝杆菌 NTM-DR 以确定大环内酯类和氨基糖苷类药物的敏感性。4 株 MABC 中有 3 株在 erm（41）的 T28 位置发生突变。所有 MAC 对两种药物均敏感。
在本研究中，MAC 是最常分离的 NTM 物种，其次是 MABC。虽然鉴定的所有 MAC 和 MABC 均对氨基糖苷类药物敏感，但由于 erm（41）基因 28 位的突变，有 3 株 MABC 对大环内酯类药物耐药。因此，临床医生需要排除 NTM，了解物种及其药物敏感性，以实现最佳病例管理。
