BackgroundImperfect sensitivity of interferon-γ release assay (IGRA) is a potential problem to detect tuberculosis. We made a thorough investigation of the factors that can lead to false negativity of IGRA.MethodsWe recruited 543 patients with new smear-positive pulmonary tuberculosis in Hanoi, Viet Nam. At diagnosis, peripheral blood was collected and IGRA (QuantiFERON-TB Gold In-Tube) was performed. Clinical and epidemiological information of the host and pathogen was collected. The test sensitivity was calculated and factors negatively influencing IGRA results were evaluated using a logistic regression model in 504 patients with culture-confirmed pulmonary tuberculosis.ResultsThe overall sensitivity of IGRA was 92.3% (95% CI, 89.6%–94.4%). The proportions of IGRA-negative and -indeterminate results were 4.8% (95% CI, 3.1%–7.0%) and 3.0% (95% CI, 1.7%–4.9%). Age increased by year, body mass index <16.0, HIV co-infection and the increased number of HLA-DRB1*0701 allele that patients bear showed significant associations with IGRA negativity (OR = 1.04 [95% CI, 1.01–1.07], 5.42 [1.48–19.79], 6.38 [1.78–22.92] and 5.09 [2.31–11.22], respectively). HIV co-infection and the same HLA allele were also associated with indeterminate results (OR = 99.59 [95% CI, 15.58–625.61] and 4.25 [1.27–14.16]).ConclusionsAging, emaciation, HIV co-infection and HLA genotype affected IGRA results. Assessment of these factors might contribute to a better understanding of the assay.

BackgroundTransmission of tuberculosis (TB) to health care workers (HCWs) is a global issue. Although effective infection control measures are expected to reduce nosocomial TB, HCWs' infection has not been assessed enough in TB high burden countries. We conducted a cross-sectional study to determine the prevalence of TB infection and its risk factors among HCWs in Hanoi, Viet Nam.Methodology/Principal FindingsA total of 300 HCWs including all staff members in a municipal TB referral hospital received an interferon-gamma release assay (IGRA), QuantiFERON-TB Gold In-TubeTM, followed by one- and two-step tuberculin skin test (TST) and a questionnaire-based interview. Agreement between the tests was evaluated by kappa statistics. Risk factors for TB infection were analyzed using a logistic regression model. Among the participants aged from 20 to 58 years (median = 40), prevalence of TB infection estimated by IGRA, one- and two-step TST was 47.3%, 61.1% and 66.3% respectively. Although the levels of overall agreement between IGRA and TST were moderate, the degree of agreement was low in the group with BCG history (kappa = 0.29). Working in TB hospital was associated with twofold increase in odds of TB infection estimated by IGRA. Increased age, low educational level and the high body mass index also demonstrated high odds ratios of IGRA positivity.Conclusions/SignificancePrevalence of TB infection estimated by either IGRA or TST is high among HCWs in the hospital environment for TB care in Viet Nam and an infection control program should be reinforced. In communities with heterogeneous history of BCG vaccination, IGRA seems to estimate TB infection more accurately than any other criteria using TST.

Beijing genotype strains are divided into two major sublineages, ancient (atypical) and modern (typical) types, but their phenotypic variations remain largely unknown. Mycobacterium tuberculosis (MTB) isolates from Hanoi, Vietnam, were analyzed by single-nucleotide polymorphisms and spoligotyping. Patient information and drug susceptibility patterns were obtained. Genetic clustering was assessed by variable number of tandem repeat (VNTR) locus sets. Multivariate analysis was also performed to investigate factors possibly associated with these sublineages. Of the 465 strains tested, 175 (37.6%) belonged to the ancient Beijing sublineage and 97 (20.9%) were of the modern Beijing sublineage. Patients with the Beijing genotype were significantly younger and more undernourished than those with non-Beijing genotype. The proportion of clustered strains calculated from 15 locus-optimized mycobacterial interspersed repetitive units [optimized-(MIRU)15]-, optimized-MIRU24-, optimized-MIRU28-, Japan Anti-Tuberculosis Association (JATA)15-, and JATA18-VNTRs were 55.7%, 49.2%, 33.8%, 44.5%, and 32.0%, respectively. Ancient and modern Beijing genotype strains were more frequently clustered than non-Beijing genotype strains, even when using VNTR sets with high discriminatory power. Isoniazid and streptomycin resistance tended to be more frequently observed in ancient Beijing strains than in modern Beijing strains and others. Our findings may provide insight into area-dependent differences in Beijing family strain characteristics.

BackgroundDiabetes mellitus (DM) is recognized as an important comorbidity for the development of tuberculosis (TB). With the increase of DM burden globally, concerns have been raised about the emerging co-epidemics of DM and TB, especially in low- and middle-income countries.MethodsA facility-based, cross-sectional study was carried out in all 30 district TB units in Hanoi, Vietnam. All eligible, diagnosed TB patients aged 15 years old or older were asked to provide consent and were screened for diabetes using fasting blood glucose (FBG). Pre-tested semi-structured questionnaires were used for collecting demographic data, lifestyle habits and clinical data. Identification of pre-diabetes or diabetes in TB patients was done in accordance to parameters set by the American Diabetes Association (2016).ResultsOf 870 eligible TB patients, 831 (95.5%) participated in the study. Of those, 241 (29%; 95%CI: 25.9–32.1%) were prediabetic and 114 (13.7%; 95%CI: 11.4–16.1%) were found to have DM. The risk of DM was higher in patients belonging to the age group 40–64 years (OR 6.09; 95%CI 2.81–13.2); or the age group 65 years or older (OR 2.65; 95%CI 1.65–4.25) or who have a family history of DM (OR 2.71; 95%CI 1.33–5.50).ConclusionsThis study demonstrated high prevalence of DM and prediabetes among TB patients in Hanoi, Vietnam. National Tuberculosis Programme needs to establish a systematic screening process for DM among TB patients.

BackgroundWasting is known as a prominent feature of tuberculosis (TB). To monitor the disease state, markers of metabolism and inflammation are potentially useful. We thus analyzed two major adipokines, adiponectin and leptin, and two other metabolic markers, fetuin-A and retinol-binding protein 4 (RBP4).MethodsThe plasma levels of these markers were measured using enzyme-linked immunosorbent assays in 84 apparently healthy individuals ( = no-symptom group) and 46 patients with active pulmonary TB around the time of treatment, including at the midpoint evaluation ( = active-disease group) and compared them with body mass index (BMI), C-reactive protein (CRP), chest radiographs and TB-antigen specific response by interferon-γ release assay (IGRA).ResultsIn the no-symptom group, adiponectin and leptin showed negative and positive correlation with BMI respectively. In the active-disease group, at the time of diagnosis, leptin, fetuin-A and RBP4 levels were lower than in the no-symptom group [adjusted means 2.01 versus 4.50 ng/ml, P<0.0001; 185.58 versus 252.27 µg/ml, P<0.0001; 23.88 versus 43.79 µg/ml, P<0.0001, respectively]. High adiponectin and low leptin levels were associated with large infiltrates on chest radiographs even after adjustment for BMI and other covariates (P = 0.0033 and P = 0.0020). During treatment, adiponectin levels increased further and then decreased. Leptin levels remained low. Initial low levels of fetuin-A and RBP4 almost returned to the normal reference range in concert with reduced CRP.ConclusionsOur data and recent literature suggest that low fat store and underlying inflammation may regulate these metabolic markers in TB in a different way. Decreased leptin, increased adiponectin, or this ratio may be a promising marker for severity of the disease independent of BMI. We should further investigate pathological roles of the balance between these adipokines.