Pulmonary diseases due to mycobacteria cause significant morbidity and mortality to human health. In addition to tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), recent epidemiological studies have shown the emergence of non-tuberculous mycobacteria (NTM) species in causing lung diseases in humans. Although more than 170 NTM species are present in various environmental niches, only a handful, primarily Mycobacterium avium complex and M. abscessus, have been implicated in pulmonary disease. While TB is transmitted through inhalation of aerosol droplets containing Mtb, generated by patients with symptomatic disease, NTM disease is mostly disseminated through aerosols originated from the environment. However, following inhalation, both Mtb and NTM are phagocytosed by alveolar macrophages in the lungs. Subsequently, various immune cells are recruited from the circulation to the site of infection, which leads to granuloma formation. Although the pathophysiology of TB and NTM diseases share several fundamental cellular and molecular events, the host-susceptibility to Mtb and NTM infections are different. Striking differences also exist in the disease presentation between TB and NTM cases. While NTM disease is primarily associated with bronchiectasis, this condition is rarely a predisposing factor for TB. Similarly, in Human Immunodeficiency Virus (HIV)-infected individuals, NTM disease presents as disseminated, extrapulmonary form rather than as a miliary, pulmonary disease, which is seen in Mtb infection. The diagnostic modalities for TB, including molecular diagnosis and drug-susceptibility testing (DST), are more advanced and possess a higher rate of sensitivity and specificity, compared to the tools available for NTM infections. In general, drug-sensitive TB is effectively treated with a standard multi-drug regimen containing well-defined first- and second-line antibiotics. However, the treatment of drug-resistant TB requires the additional, newer class of antibiotics in combination with or without the first and second-line drugs. In contrast, the NTM species display significant heterogeneity in their susceptibility to standard anti-TB drugs. Thus, the treatment for NTM diseases usually involves the use of macrolides and injectable aminoglycosides. Although well-established international guidelines are available, treatment of NTM disease is mostly empirical and not entirely successful. In general, the treatment duration is much longer for NTM diseases, compared to TB, and resection surgery of affected organ(s) is part of treatment for patients with NTM diseases that do not respond to the antibiotics treatment. Here, we discuss the epidemiology, diagnosis, and treatment modalities available for TB and NTM diseases of humans.

中文翻译：

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结核病和非结核分枝杆菌感染 - 流行病学、诊断和治疗的比较分析。


分枝杆菌引起的肺部疾病对人类健康造成显着的发病率和死亡率。除了由结核分枝杆菌 (Mtb) 引起的结核病 (TB) 之外，最近的流行病学研究表明，非结核分枝杆菌 (NTM) 物种的出现也会引起人类肺部疾病。尽管各种环境生态位中存在 170 多种 NTM 物种，但只有少数（主要是鸟分枝杆菌复合体和脓肿分枝杆菌）与肺部疾病有关。结核病是通过吸入有症状的患者产生的含有结核分枝杆菌的气溶胶飞沫传播的，而非结核分枝杆菌疾病主要是通过环境中产生的气溶胶传播的。然而，吸入后，Mtb 和 NTM 都会被肺部的肺泡巨噬细胞吞噬。随后，各种免疫细胞从循环系统募集到感染部位，导致肉芽肿形成。尽管结核病和 NTM 疾病的病理生理学有一些共同的基本细胞和分子事件，但宿主对 Mtb 和 NTM 感染的易感性是不同的。结核病和非结核分枝杆菌病例之间的疾病表现也存在显着差异。虽然 NTM 疾病主要与支气管扩张有关，但这种情况很少是结核病的诱发因素。同样，在人类免疫缺陷病毒 (HIV) 感染者中，NTM 疾病表现为播散性肺外形式，而不是 Mtb 感染中所见的粟粒性肺部疾病。与 NTM 感染的可用工具相比，结核病的诊断方式，包括分子诊断和药物敏感性测试 (DST) 更先进，并且具有更高的敏感性和特异性。 一般来说，药物敏感结核病可以通过包含明确的一线和二线抗生素的标准多药治疗方案得到有效治疗。然而，耐药结核病的治疗需要额外的新型抗生素，并与或不与一线和二线药物联合使用。相比之下，NTM 物种对标准抗结核药物的敏感性表现出显着的异质性。因此，NTM疾病的治疗通常涉及使用大环内酯类和注射用氨基糖苷类药物。尽管已有完善的国际指南，但 NTM 疾病的治疗大多是经验性的，并不完全成功。一般来说，与结核病相比，NTM 疾病的治疗持续时间要长得多，并且对抗生素治疗无反应的 NTM 疾病患者的治疗包括受影响器官的切除手术。在这里，我们讨论人类结核病和非结核分枝杆菌疾病的流行病学、诊断和治疗方式。