Department of Microbiology, Malekan Branch, Islamic Azad University, Malekan, Iran.
Front Cell Infect Microbiol. 2024 Oct 24;14:1477015. doi: 10.3389/fcimb.2024.1477015. eCollection 2024.
The incidence of nontuberculous mycobacterial (NTM) infections has increased worldwide, attracting attention in routine diagnostic settings, particularly among patients with suspected tuberculosis. This study aimed to acquire knowledge of NTM infections in patients with suspected tuberculosis and to evaluate the genetic diversity of the strains.
In this study, 230 clinical specimens were collected from suspected tuberculosis patients. Following decontamination with N-Acetyl-L-cysteine-sodium hydroxide (NALC-NaOH), the sediments of specimens were inoculated onto Löwenstein-Jensen medium and then incubated at 37°C for 8 weeks. The samples that yielded positive cultures were evaluated through the sequencing of conserved fragments of and . For those samples that were not identified as part of the complex (MTC) by PCR, further analysis was conducted via PCR to detect fragments of the gene.
Twenty-one NTM species were isolated from 230 clinical specimens (14 NTM from pulmonary specimens and 7 from extrapulmonary specimens). Among these, 12 (57.14%) were rapid-growing mycobacteria (RGM), and 9 (42.85%) were slow-growing mycobacteria (SGM). No complex (MAC) was identified in any of the specimens. Notably, the , , and strains presented significant genetic diversity.
The prevalence of infections attributed to nontuberculous species surpasses that attributed to tuberculosis. These findings underscore the importance of exploring NTM species in individuals suspected of having TB.
非结核分枝杆菌（NTM）感染的发病率在全球范围内有所增加，在常规诊断环境中引起了关注，特别是在疑似结核病患者中。本研究旨在了解疑似结核病患者的 NTM 感染情况，并评估菌株的遗传多样性。
本研究共收集了 230 份疑似结核病患者的临床标本。经 N-乙酰-L-半胱氨酸-氢氧化钠（NALC-NaOH）去污处理后，将标本沉淀物接种于 Löwenstein-Jensen 培养基，在 37°C 下孵育 8 周。对阳性培养物进行评价，包括测序 和 基因的保守片段。对于那些未通过 PCR 鉴定为结核分枝杆菌复合群（MTC）的样本，进一步通过 PCR 检测 基因片段进行分析。
从 230 份临床标本中分离出 21 种 NTM （14 种来自肺部标本，7 种来自肺外标本）。其中，12 种（57.14%）为快速生长型分枝杆菌（RGM），9 种（42.85%）为缓慢生长型分枝杆菌（SGM）。任何标本中均未鉴定出结核分枝杆菌复合群（MAC）。值得注意的是， 、 和 菌株表现出显著的遗传多样性。
非结核分枝杆菌感染的患病率超过了结核病。这些发现强调了在疑似结核病患者中探索非结核分枝杆菌的重要性。
