Department of Medicine, Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA.
Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA.
Clin Infect Dis. 2021 Jun 15;72(12):e931-e937. doi: 10.1093/cid/ciaa1665.
Nontuberculous mycobacteria (NTM) are a rare cause of infectious tenosynovitis of the upper extremity. Using molecular methods, clinical microbiology laboratories are increasingly reporting identification down to the species level. Improved methods for speciation are revealing new insights into the clinical and epidemiologic features of rare NTM infections.
We encountered 3 cases of epidemiologically linked upper extremity NTM tenosynovitis associated with exposure to hurricane-damaged wood. We conducted whole-genome sequencing to assess isolate relatedness followed by a literature review of NTM infections that involved the upper extremity.
Despite shared epidemiologic risk, the cases were caused by 3 distinct organisms. Two cases were rare infections caused by closely related but distinct species within the Mycobacterium terrae complex that could not be differentiated by traditional methods. The third case was caused by Mycobacterium intracellulare. An updated literature review that focused on research that used modern molecular speciation methods found that several species within the M. terrae complex are increasingly reported as a cause of upper extremity tenosynovitis, often in association with environmental exposures.
These cases illustrate the importance of molecular methods for speciating phenotypically similar NTM, as well as the limitations of laboratory-based surveillance in detecting point-source outbreaks when the source is environmental and may involve multiple organisms.
非结核分枝杆菌（NTM）是引起上肢感染性腱鞘炎的罕见原因。使用分子方法，临床微生物学实验室越来越多地报告鉴定到种的水平。种系鉴定方法的改进，揭示了稀有 NTM 感染的临床和流行病学特征的新见解。
我们遇到了 3 例与飓风破坏的木材接触有关的具有流行病学相关性的上肢 NTM 腱鞘炎。我们进行了全基因组测序来评估分离株的相关性，然后对涉及上肢的 NTM 感染进行文献复习。
尽管存在共同的流行病学风险，但这些病例是由 3 种不同的病原体引起的。2 例为罕见感染，由分枝杆菌 terrae 复合体中密切相关但不同的物种引起，传统方法无法区分。第三种情况是由细胞内分枝杆菌引起的。一项更新的文献综述侧重于使用现代分子种系鉴定方法的研究，发现分枝杆菌 terrae 复合体中的几种物种越来越多地被报道为上肢腱鞘炎的原因，通常与环境暴露有关。
这些病例说明了对表型相似的 NTM 进行分子种系鉴定的重要性，以及当来源是环境且可能涉及多种生物体时，基于实验室的监测在检测点源暴发方面的局限性。
