Department of Infectious Diseases and Tropical Medicine (DITM), Medical Center of the University of Munich (LMU), Munich, Germany.
Ministère de la Santé, Institut National d'Hygiène (INH), Lomé, Togo.
BMC Infect Dis. 2019 Aug 28;19(1):753. doi: 10.1186/s12879-019-4349-9.
Leprosy continues to be a health problem in endemic areas. More than 200,000 new cases of leprosy per year suggest that transmission of the disease is still ongoing, presumably as airborne infection through nasal droplets. Late diagnosis supports continued transmission and increases the individual risk for functional disabilities. Laboratory tools are considered beneficial to facilitate early detection and clinical assessment of cases. The aim of this study was to validate molecular tools allowing detection, quantification and assessment of viability of M. leprae from nasal swab samples which are easy to obtain without the need of any invasive procedures.
Validation of two real-time PCRs detecting M. leprae DNA (RLEP qPCR) and RNA (16S rRNA RT qPCR) was conducted on "must not detect"/"must detect" samples and 160 pre-treatment nasal swab samples from 20 clinically diagnosed multibacillary (MB) leprosy patients from Togo.
Both assays were 100% M. leprae specific and showed analytical sensitivities of three templates each. Out of 20 clinically diagnosed MB leprosy patients, 15 (75.0%) had a positive RLEP qPCR result from nasal swab samples. The 16S rRNA RT qPCR detected viable bacilli in nasal swab samples of ten out of these 15 RLEP positive patients (66.7%).
The combined RLEP/16S rRNA (RT) qPCR assay provides a sensitive and specific tool to determine the bacterial load and viability of M. leprae from nasal swab samples and is applicable for early diagnosis, monitoring treatment response and investigating the role of nasal carriage of M. leprae in human-to-human transmission through aerosol infection.
麻风病在流行地区仍然是一个健康问题。每年超过 20 万例新的麻风病例表明，这种疾病的传播仍在继续，可能是通过鼻飞沫进行空气传播。延迟诊断支持持续传播，并增加个体功能障碍的风险。实验室工具被认为有助于促进早期发现和临床评估病例。本研究的目的是验证分子工具，以便从容易获得的鼻拭子样本中检测、定量和评估麻风分枝杆菌的活力，而无需任何侵入性程序。
对“不得检出”/“必须检出”样本和来自多菌型麻风病（MB）20 例临床诊断患者的 160 例治疗前鼻拭子样本进行两种实时 PCR（检测麻风分枝杆菌 DNA（RLEP qPCR）和 16S rRNA RT qPCR）的验证。
两种检测方法均对麻风分枝杆菌具有 100%的特异性，每种检测方法均具有三种模板的分析灵敏度。在 20 例临床诊断的 MB 麻风病患者中，15 例（75.0%）的鼻拭子样本中 RLEP qPCR 结果为阳性。16S rRNA RT qPCR 在这 15 例 RLEP 阳性患者中的 10 例（66.7%）的鼻拭子样本中检测到有活力的杆菌。
RLEP/16S rRNA（RT）qPCR 联合检测法提供了一种敏感和特异的工具，可从鼻拭子样本中确定麻风分枝杆菌的载量和活力，适用于早期诊断、监测治疗反应，并研究麻风分枝杆菌在人-人传播中的鼻携带作用通过空气传播。
