OBJECTIVE: A new loop-mediated isothermal amplification (LAMP) test kit, including a simple DNA extraction device for the detection of Mycobacterium tuberculosis complex, was developed for commercial use and evaluated for its usefulness in diagnosing tuberculosis (TB). DESIGN: The LAMP test was performed using untreated and N-acetyl-L-cysteine (NALC) NaOH-treated sputum specimen. The efficiency of the kit was compared with other conventional laboratory examinations, including other nucleic acid amplification (NAA) tests. RESULTS: The sensitivity of LAMP using raw sputum (direct LAMP) in smear- and culture-positive specimens was 98.2% (95%CI 94.9–99.4), while the sensitivity in smear-negative, culture-positive specimens was 55.6% (95%CI 43.4–68.0). The diagnostic sensitivity of direct LAMP for the diagnosis of individuals with TB was 88.2% (95%CI 81.4–92.7). The sensitivity values of direct LAMP were slightly, but not statistically significantly lower than those of Cobas Amplicor MTB and TRC Rapid MTB, while the sensitivity of the LAMP test using NALC-NaOH treated sputum was significantly lower than other NAA tests (P < 0.05) for smear-negative, culture-positive specimens. The new commercial version of the LAMP kit was easy to handle and yielded results within 1 h of receiving sputum specimens. CONCLUSIONS: This test is considered a promising diagnostic tool for TB, even for peripheral laboratories with limited equipment, such as those in developing countries.

BACKGROUND. Inadequate tuberculosis (TB) diagnostics are a major hurdle in the reduction of disease burden, and accurate point-of-care tests (POCTs) are urgently needed. We assessed the diagnostic accuracy of Fujifilm SILVAMP TB lipoarabinomannan (FujiLAM) POCT for TB diagnosis in HIV-negative outpatients and compared it with Alere Determine TB LAM Ag (AlereLAM) POCT and a laboratory-based ultrasensitive electrochemiluminescence LAM research assay (EclLAM). METHODS. In this multicenter diagnostic test accuracy study, we recruited HIV-negative adults with symptoms suggestive of pulmonary TB presenting to outpatient health care centers in Peru and South Africa. Urine samples were tested using FujiLAM, AlereLAM, and EclLAM, and the diagnostic accuracy was assessed against a microbiological reference standard (MRS) and a composite reference standard. RESULTS. Three hundred seventy-two HIV-negative participants were included and the prevalence of microbiologically confirmed TB was 30%. Compared with the MRS, the sensitivities of AlereLAM, FujiLAM, and EclLAM were 10.8% (95% confidence interval [CI] 6.3%–18.0%), 53.2% (95% CI 43.9%–62.1%), and 66.7% (95% CI 57.5%–74.7%), respectively. The specificities of AlereLAM, FujiLAM, and EclLAM were 92.3% (95% CI 88.5%–95.0%), 98.9% (95% CI 96.7%–99.6%), and 98.1% (95% CI 95.6%–99.2%), respectively. Positive likelihood ratios of AlereLAM, FujiLAM, and EclLAM were 1.4, 46.2, and 34.8, respectively, and positive predictive values were 37.5%, 95.2%, and 93.7%, respectively. CONCLUSION. Compared with AlereLAM, FujiLAM detected 5 times more patients with TB in HIV-negative participants, had a high positive predictive value, and has the potential to improve rapid diagnosis of TB at the point-of-care. EclLAM demonstrated that additional sensitivity gains are possible, which highlights LAM’s potential as a biomarker. Additional research is required to assess FujiLAM’s performance in prospective cohorts, its cost-effectiveness, and its impact in real-world clinical settings. FUNDING. Global Health Innovative Technology Fund, the UK Department for International Development, the Dutch Ministry of Foreign Affairs, the Bill and Melinda Gates Foundation, the Australian Department of Foreign Affairs and Trade, the German Federal Ministry of Education and Research through Kreditanstalt für Wiederaufbau, and the NIH and National Institute of Allergy and Infectious Diseases.

Tuberculosis (TB) is the most common cause of death in people living with HIV (PLHIV), yet TB often goes undiagnosed since many patients are not able to produce a sputum specimen, and traditional diagnostics are costly or unavailable. A novel, rapid lateral flow assay, Fujifilm SILVAMP TB LAM (SILVAMP-LAM), detects the presence of TB lipoarabinomannan (LAM) in urine, and is substantially more sensitive for diagnosing TB in PLHIV than an earlier LAM assay (Alere Determine TB LAM lateral flow assay [LF-LAM]). Here, we present an individual participant data meta-analysis of the diagnostic accuracy of SILVAMP-LAM in adult PLHIV, including both published and unpublished data. Adult PLHIV (≥18 years) were assessed in 5 prospective cohort studies in South Africa (3 cohorts), Vietnam, and Ghana, carried out during 2012 to 2017. Of the 1,595 PLHIV who met eligibility criteria, the majority (61%) were inpatients, median age was 37 years (IQR 30–43), 43% had a CD4 count ≤ 100 cells/μl, and 35% were receiving antiretroviral therapy. Most participants (94%) had a positive WHO symptom screen for TB on enrollment, and 45% were diagnosed with microbiologically confirmed TB, using mycobacterial culture or Xpert MTB/RIF testing of sputum, urine, or blood. Previously published data from inpatients were combined with unpublished data from outpatients. Biobanked urine samples were tested, using blinded double reading, with SILVAMP-LAM and LF-LAM. Applying a microbiological reference standard for assessment of sensitivity, the overall sensitivity for TB detection was 70.7% (95% CI 59.0%–80.8%) for SILVAMP-LAM compared to 34.9% (95% CI 19.5%–50.9%) for LF-LAM. Using a composite reference standard (which included patients with both microbiologically confirmed as well as clinically diagnosed TB), SILVAMP-LAM sensitivity was 65.8% (95% CI 55.9%–74.6%), and that of LF-LAM 31.4% (95% CI 19.1%–43.7%). In patients with CD4 count ≤ 100 cells/μl, SILVAMP-LAM sensitivity was 87.1% (95% CI 79.3%–93.6%), compared to 56.0% (95% CI 43.9%–64.9%) for LF-LAM. In patients with CD4 count 101–200 cells/μl, SILVAMP-LAM sensitivity was 62.7% (95% CI 52.4%–71.9%), compared to 25.3% (95% CI 15.8%–34.9%) for LF-LAM. In those with CD4 count > 200 cells/μl, SILVAMP-LAM sensitivity was 43.9% (95% CI 34.3%–53.9%), compared to 10.9% (95% CI 5.2%–18.4%) for LF-LAM. Using a microbiological reference standard, the specificity of SILVAMP-LAM was 90.9% (95% CI 87.2%–93.7%), and that of LF-LAM 95.3% (95% CI 92.2%–97.7%). Limitations of this study include the use of biobanked, rather than fresh urine samples, and testing by skilled laboratory technicians in research laboratories, rather than at the point of care. In this study, we found that SILVAMP-LAM identified a substantially higher proportion of TB patients in PLHIV than LF-LAM. The sensitivity of SILVAMP-LAM was highest in patients with CD4 count ≤ 100 cells/μl. Further work is needed to demonstrate accuracy when implemented as a point-of-care test.

The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450 m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.