Mouse Anti-M. tuberculosis 16kDa Monoclonal antibody, clone 6286

Objectives: The rapid diagnosis of tuberculosis (TB) is important for patient treatment and infection control. Current molecular diagnostic techniques for TB have insufficient sensitivity to detect samples with low bacterial loads. The sensitivity of molecular testing depends on not only the performance of the assay technique but also the nucleic acid extraction method. Here, we present a novel approach using exosomal DNA (exoDNA) and droplet digital PCR (ddPCR) platforms to detect Mycobacterium tuberculosis DNA in clinical samples. Methods: The ddPCR platform targeting IS6110 was evaluated in parallel using total DNA and exoDNA. The clinical performance of ddPCR method was assessed with 190 respiratory samples from patients with suspected pulmonary TB. Results: Compared with mycobacterial culture, sensitivity and specificity of ddPCR were 61.5% (95% CI 44.6-76.6%) and 98.0% (95% CI 94.3-99.6%) using total DNA, and 76.9% (95% CI 60.7-88.9%) and 98.0% (95% CI 94.3-99.6%) using exoDNA, respectively. Among 15 culture -positive specimens with low con- centrations of target molecules (2 similar to 99 positive droplets with exoDNA), only 53.3% (8/15), 46.7% (7/15), and 26.7% (4/15) of cases were detected using ddPCR with total DNA, real-time PCR with exoDNA, and real-time PCR with total DNA, respectively. Discussion: Our platform using ddPCR and exoDNA has the potential to provide sensitive and accurate methodology for TB diagnosis. S.M. Cho, Clin Microbiol Infect 2020;26:942.e1 - 942.e5

Tuberculosis (TB) represents a health problem in Colombia, and its control is focused on the search for contacts and treatment of TB cases underscoring the role of latent tuberculosis infection (LTBI) as a reservoir of Mycobacterium tuberculosis. The burden of LTBI in Colombia is unknown. We aimed to estimate the prevalence of LTBI and identify the associated risk factors. In this cross-sectional study, we recruited participants from four health care centers in Cali, Colombia. The participants were eligible if they were aged between 14 and 70 years, and all participants answered a survey evaluating their medical history and sociodemographic and lifestyle factors. LTBI status was based on tuberculin skin test (TST) positivity using two thresholds: >= 10 mm (TST-10) and >= 15 mm (TST-15). The magnitude of the associations between independent factors and dependent outcomes (LTBI status and TST induration) were evaluated by logistic regression and generalized linear models, respectively. A total of 589 individuals were included with TST positivity rates of 25.3% (TST-10) and 13.2% (TST-15). Logistic regression showed that being between age 40 and 69 years (OR = 7.28, 95% CI [1.62-32.7]), being male (OR = 1.71, 95% CI [1.04-2.84]), being employed (OR = 1.56, 95% CI [1.02-2.38]), and having a low intake of alcohol (OR = 2.40, 95% CI [1.13-5.11]) were risk factors for TST positivity, while living in the north zone (OR = 0.32, 95% CI [0.18-0.55]), living in the suburb zone (OR = 0.28, 95% CI [0.15-0.52]) and having a secondary education (OR = 0.49 95% CI [0.29-0.83]) lowered the risk of TST positivity. The generalized linear model showed that the previous predictors, as well as a low body mass index, had an effect on TST reaction size. The LTBI prevalence found in the population was moderate, reflecting the continuous transmission of M. tuberculosis. Social factors seem to play a decisive role in the risk of LTBI. Employed males, who are over 40 years of age, are overweight, have a lower level of education and have a low intake of alcohol (50-100 mL, once/week) should be a priority group for prophylactic treatment as a strategy for TB control in this city.