BackgroundA new generation of diagnostic tests, the interferon-γ release assays (IGRAs), have been developed for the detection of latent tuberculosis infection (LTBI). Limited data are available on their use in HIV-infected persons.MethodsA cross-sectional study was carried out at 2 HIV clinics in Atlanta to assess the utility of two IGRA tests (T-SPOT.TB [TSPOT] and QuantiFERON-TB Gold in Tube [QFT-3G]) compared to the tuberculin skin test (TST).Results336 HIV-infected persons were enrolled. Median CD4 count was 335 cells/μl and median HIV viral load was 400 copies/ml. Overall, 27 patients (8.0%) had at least 1 positive diagnostic test for LTBI: 7 (2.1%) had a positive TST; 9 (2.7%) a positive QFT-3G; and 14 (4.2%) a positive TSPOT. Agreement between the 3 diagnostic tests was poor: TST and TSPOT, [κ = 0.16, 95% CI (-0.06, 0.39)], TST and QFT-3G [κ = 0.23, 95% CI (-0.05, 0.51)], QFT-3G and TSPOT [κ = 0.06, 95% CI (-0.1, 0.2)]. An indeterminate test result occurred among 6 (1.8%) of QFT-3G and 47 (14%) of TSPOT tests. In multivariate analysis, patients with a CD4 ≤ 200 cells/μl were significantly more likely to have an indeterminate result [OR = 3.6, 95% CI (1.9, 6.8)].ConclusionWe found a low prevalence of LTBI and poor concordance between all 3 diagnostic tests. Indeterminate test results were more likely at CD4 counts ≤ 200 cells/μl. Additional studies among HIV-infected populations with a high prevalence of TB are needed to further assess the utility of IGRAs in this patient population.

Close contacts to infectious patients with tuberculosis had high rates of tuberculosis, with most disease diagnosed before or within 3 months after the index patient' diagnosis. Contact investigations need to be prompt to detect tuberculosis and maximize the opportunity to identify and treat latent infection, to prevent disease.

An expanded respiratory isolation policy was implemented in a public hospital that cares for about 200 patients with active tuberculous each year. This led to proper isolation of > or = 95% of patients with tuberculosis on admission but involved an 8-fold overuse of isolation rooms. We developed a model policy to decrease overisolation of nontuberculous patients. Clinical findings in 295 patients admitted to respiratory isolation during a 3-mo period were evaluated for their usefulness in determining which patients had tuberculosis. Multivariate analysis identified five predictive variables: chest radiograph with upper lobe infiltrate (odds ratio, 5.00; CI, 2.38 to 10.51; p = 0.001) or cavity (odds ratio, 3.93; CI, 1.06 to 14.62; p = 0.041), history of having known someone with tuberculosis (odds ratio, 2.42; CI, 1.10 to 5.32, p = 0.027), self-reported positive tuberculin skin test (odds ratio, 5.67; CI, 1.57 to 22.01; p = 0.009), self-reported isoniazid preventive therapy (odds ratio, 0.18; CI, 0.04 to 0.82; p = 0.027). Using these variables to determine which patients required isolation would have decreased the number of isolated nontuberculous patients from 253 to 95, but it would have missed eight of 42 patients with tuberculosis. Further work is needed to identify clinical predictors that would decrease overuse of isolation beds while maintaining satisfactory sensitivity for patients with tuberculosis.

SUMMARY SETTING Although diabetes mellitus (DM) is an established risk factor for active tuberculosis (TB) disease, little is known about the association between pre-DM, DM, and latent tuberculous infection (LTBI). OBJECTIVE To estimate the association between DM and LTBI. DESIGN We conducted a cross-sectional study among recently arrived refugees seen at a health clinic in Atlanta, GA, USA, between 2013 and 2014. Patients were screened for DM using glycosylated-hemoglobin (HbA1c), and for LTBI using the QuantiFERON®-TB (QFT) test. HbA1c and QFT results, demographic information, and medical history were abstracted from patient charts. RESULTS Among 702 included patients, 681 (97.0%) had HbA1c and QFT results. Overall, 54 (7.8%) patients had DM and 235 (33.8%) had pre-DM. LTBI was prevalent in 31.3% of the refugees. LTBI prevalence was significantly higher (P < 0.01) among patients with DM (43.4%) and pre-DM (39.1%) than in those without DM (25.9%). Refugees with DM (adjusted OR [aOR] 2.3, 95%CI 1.2–4.5) and pre-DM (aOR 1.7, 95%CI 1.1–2.4) were more likely to have LTBI than those without DM. CONCLUSION Refugees with DM or pre-DM from high TB burden countries were more likely to have LTBI than those without DM. Dysglycemia may impair the immune defenses involved in preventing Mycobacterium tuberculosis infection.