Introduction. Disease caused by non-tuberculous mycobacteria (NTM) is an emergent problem. Because NTM pulmonary disease and tuberculosis (TB) have similar clinical presentations, many cases of NTM may be misdiagnosed as TB before laboratory identification of the NTM species. Hypothesis/Gap Statement. Clinical laboratories should always perform differentiation between Mycobacterium tuberculosis complex (MTBC) and NTM to guide patients' correct treatment. Aim. To describe the characteristics and to identify mycobacterial isolates presumptively classified as MTBC by macroscopic characteristics in culture media that tested negative in GenoType MTBDRplus. Methodology. All cultures from February 2019 to December 2021 showing MTBC macroscopic characteristics were processed by GenoType MTBDRplus. MTBC-negative cultures underwent species identification by immunochromatography, line probe assays and PRA-hsp65. Patients’ data were obtained from Brazilian surveillance systems. Results. Only 479 (3.1%) of 15 696 isolates presumptively identified as MTBC were not confirmed by GenoType MTBDRplus and were then subjected to identification. A total of 344 isolates were shown to be NTM, of which 309 (64.5%) and 35 (7.3%) were identified to the species and genus levels, respectively. Of the 204 NTM isolates with MTBC characteristics, the most frequent species were M. fortuitum (n=52, 25.5%), M. abscessus complex (MABC; n=27, 13.2%) and M. avium complex (MAC; n=26, 12.7%). Regarding the GenoType MTBDRplus results from NTM isolates, there were diverse hybridisation profiles with rpoB gene’s different wild-type (WT) probes. Seventy-six (16.1%) of the 473 patients were classified as having NTM disease, the most frequent being MAC (n=15, 19.7%), MABC (n=13, 17.1%), M. kansasii (n=10, 13.2%) and M. fortuitum (n=6, 7.9%). Conclusion. Because the signs and symptoms of pulmonary TB are similar to those of pulmonary mycobacteriosis and treatment regimens for TB and NTM are different, identifying the disease-causing species is paramount to indicate the correct management. Thus, in the laboratory routine, when an isolate presumptively classified as MTBC is MTBC-negative, it is still essential to perform subsequent identification.

中文翻译：

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GenoType MTBDRplus 检测中的非结核分枝杆菌杂交图谱：来自高通量实验室诊断常规的经验

介绍。由非结核分枝杆菌（NTM）引起的疾病是一个紧迫的问题。由于 NTM 肺病和结核病 (TB) 具有相似的临床表现，因此在实验室鉴定 NTM 种类之前，许多 NTM 病例可能会被误诊为 TB。假设/差距陈述。临床实验室应经常对结核分枝杆菌复合群（MTBC）和NTM进行鉴别，以指导患者正确治疗。目的。描述特征并通过在 GenoType MTBDR plus中测试为阴性的培养基中的宏观特征来识别推定分类为 MTBC 的分枝杆菌分离株。方法。 2019 年 2 月至 2021 年 12 月显示 MTBC 宏观特征的所有培养物均由 GenoType MTBDR plus处理。 MTBC 阴性培养物通过免疫层析、线性探针测定和 PRA- hsp65进行物种鉴定。患者数据来自巴西监测系统。结果。在 15 696 个推定为 MTBC 的分离株中，只有 479 个 (3.1%) 未被 GenoType MTBDR plus确认，然后进行了鉴定。共有 344 个分离株被证明为 NTM，其中 309 个（64.5%）和 35 个（7.3%）分别被鉴定到种和属水平。在 204 个具有 MTBC 特征的 NTM 分离株中，最常见的种类是偶发分枝杆菌( n = 52，25.5%)、脓肿分枝杆菌复合体 (MABC ；n = 27，13.2%) 和鸟分枝杆菌复合体 (MAC ；n = 26, 12.7%）。关于 NTM 分离株的 GenoType MTBDR plus结果， rpoB基因的不同野生型 (WT) 探针存在多种杂交图谱。 473 名患者中有 76 名 (16.1%) 被归类为患有 NTM 疾病，最常见的是 MAC ( n =15, 19.7%)、MABC ( n =13, 17.1%)、M. kansasii ( n =10, 13.2%) 和偶发分枝杆菌( n =6, 7.9%)。结论。由于肺结核的体征和症状与肺分枝杆菌病相似，而且结核病和非结核分枝杆菌的治疗方案不同，因此识别致病菌对于正确治疗至关重要。因此，在实验室常规中，当推定为MTBC的分离株为MTBC阴性时，仍然有必要进行后续鉴定。