Background
Improved tests to diagnose latent TB infection (LTBI) are needed. We sought to evaluate the performance of two commercially available interferon-gamma release assays (IGRAs) compared to the tuberculin skin test (TST) for the diagnosis of LTBI and to identify risk factors for LTBI among HIV-infected individuals in Georgia, a country with high rates of TB.
Methods
HIV-patients were enrolled from the National AIDS Center in Tbilisi, Georgia. After providing informed consent, each participant completed a questionnaire, had blood drawn for QuantiFERON-TB Gold in-Tube (QFT-GIT) and T-SPOT.TB testing and had a TST placed. The TST was read at 48–72 hrs with ≥ 5 mm induration considered positive.
Results
Between 2009–2011, 240 HIV-infected persons (66% male) with a median age of 38 years and a median CD4 count of 255 cells/μl (IQR: 124–412) had diagnostic testing for LTBI performed. 94% had visible evidence of a BCG scar. The TST was positive in 41 (17%) patients; QFT-GIT in 70 (29%); and T-SPOT.TB in 56 (24%). At least one diagnostic test was positive in 109 (45%) patients and only among 13 (5%) patients were all three tests positive. Three (1%) QFT-GIT and 19 (8%) T-SPOT.TB test results were indeterminate. The agreement among all pairs of tests was poor: QFT-GIT vs. T-SPOT.TB (κ = 0.18, 95% CI .07-.30), QFT-GIT vs. TST (κ = 0.29, 95% CI .16-.42), and TST vs. T-SPOT.TB (κ = 0.22, 95% CI .07-.29). Risk factors for LTBI varied by diagnostic test and none showed associations between positive test results and well-known risk factors for TB, such as imprisonment, drug abuse and immunological status.
Conclusions
A high proportion of HIV patients had at least one positive diagnostic test for LTBI; however, there was very poor agreement among all tests. This lack of agreement makes it difficult to know which test is superior and most appropriate for LTBI testing among HIV-infected patients. While further follow-up studies will help determine the predictive ability of different LTBI tests, improved modalities are needed for accurate detection of LTBI and assessment of risk of developing active TB among HIV-infected patients.
Objectives: To determine risk factors for poor outcomes among patients with pulmonary multidrug- or extensively drug-resistant (M/XDR) tuberculosis (TB) in Georgia. Methods: This was a prospective, population-based observational cohort study. Results: Among 380M/XDR-TB patients (mean age 38 years), 179 (47%) had a poor outcome: 59 (16%) died, 37 (10%) failed, and 83 (22%) defaulted. Newly diagnosed M/XDR-TB cases were significantly more likely to have a favorable outcome than retreatment cases (odds ratio (OR) 4.26, 95% confidence interval (CI) 1.99-9.10, p<0.001). In the multivariable analysis, independent risk factors for a poor treatment outcome included previous treatment history (OR 2.92, 95% CI 1.29-6.58), bilateral disease (OR 1.90, 95% CI 1.20-3.01), body mass index (BMI, kg/m2) ≤18.5 (OR 1.91, 95% CI 1.11-3.29), and XDR-TB (OR 2.28, 95% CI 1.11-4.71). Patients who underwent surgical resection (OR 0.27, 95% CI 0.11-0.64) and had sputum culture conversion by 4 months (OR 0.33, 95% CI 0.21-0.52) were significantly less likely to have poor treatment outcomes. Conclusions: Adjunctive surgery appeared to be beneficial in treating patients with M/XDR-TB. Retreatment cases, XDR-TB, bilateral disease, and low BMI were associated with a poor outcome. Additional studies are needed to further define the apparent beneficial role of surgery in the treatment of M/XDR-TB.
Background
The country of Georgia has a high prevalence of tuberculosis (TB) and hepatitis C virus (HCV) infection.
Purpose
To determine whether HCV co-infection increases the risk of incident drug-induced hepatitis among patients on first-line anti-TB drug therapy.
Methods
Prospective cohort study; HCV serology was obtained on all study subjects at the time of TB diagnosis; hepatic enzyme tests (serum alanine aminotransferase [ALT] activity) were obtained at baseline and monthly during treatment.
Results
Among 326 study patients with culture-confirmed TB, 68 (21%) were HCV co-infected, 14 (4.3%) had chronic hepatitis B virus (HBV) infection (hepatitis B virus surface antigen positive [HBsAg+]), and 6 (1.8%) were HIV co-infected. Overall, 19% of TB patients developed mild to moderate incident hepatotoxicity. In multi-variable analysis, HCV co-infection (adjusted Hazards Ratio [aHR]=3.2, 95% CI=1.6-6.5) was found to be an independent risk factor for incident anti-TB drug-induced hepatotoxicity. Survival analysis showed that HCV co-infected patients developed hepatitis more quickly compared to HCV seronegative patients with TB.
Conclusion
A high prevalence of HCV co-infection was found among patients with TB in Georgia. Drug-induced hepatotoxicity was significantly associated with HCV co-infection but severe drug-induced hepatotoxicity (WHO grade III or IV) was rare.
Tuberculosis (TB) is a major global health problem. Patients with TB have a high rate of vitamin D deficiency, both at diagnosis and during the course of treatment with anti-tuberculosis drugs. Although data on the efficacy of vitamin D supplementation on Mycobacterium tuberculosis (Mtb) clearance are uncertain from randomized controlled trials (RCTs), vitamin D enhances the expression of the anti-microbial peptide human cathelicidin (hCAP18) in cultured macrophages in vitro. One possible explanation for the mixed (primarily negative) results of RCTs examining vitamin D treatment in TB infection is that anti-TB drugs given to enrolled subjects may impact actions of vitamin D to enhance cathelicidin in macrophages. To address this hypothesis, human macrophage-like monocytic (THP-1) cells were treated with varying doses of first-line anti-tuberculosis drugs in the presence of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). The expression of hCAP18 was determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). 1,25(OH)2D3 strongly induced expression of hCAP18 mRNA in THP-1 cells (fold-change from control). The combination of the standard 4-drug TB therapy (isoniazid, rifampicin, pyrazinamide and ethambutol) in the cultured THP-1 cells demonstrated a significant decrease in hCAP18 mRNA at the dosage of 10 µg/mL. In 31 subjects with newly diagnosed drug-sensitive TB randomized to either high-dose vitamin D3 (1.2 million IU over 8 weeks, n = 13) versus placebo (n = 18), there was no change from baseline to week 8 in hCAP18 mRNA levels in peripheral blood mononuclear cells or in plasma concentrations of LL-37, the protein product of hCAP18. These data suggest that first-line anti-TB drugs may alter the vitamin D-dependent increase in hCAP18 and LL-37 human macrophages.
Background: The WHO has recommended the implementation of rapid diagnostic tests to detect and help combat M/XDR tuberculosis (TB). There are limited data on the performance and impact of these tests in field settings. Methods: The performance of the commercially available Genotype MTBDRplus molecular assay was compared to conventional methods including AFB smear, culture and drug susceptibility testing (DST) using both an absolute concentration method on Löwenstein-Jensen media and broth-based method using the MGIT 960 system. Sputum specimens were obtained from TB suspects in the country of Georgia who received care through the National TB Program. Results: Among 500 AFB smear-positive sputum specimens, 458 (91.6%) had both a positive sputum culture for Mycobacterium tuberculosis and a valid MTBDRplus assay result. The MTBDRplus assay detected isoniazid (INH) resistance directly from the sputum specimen in 159 (89.8%) of 177 specimens and MDR-TB in 109 (95.6%) of 114 specimens compared to conventional methods. There was high agreement between the MTBDRplus assay and conventional DST results in detecting MDR-TB (kappa = 0.95, p < 0.01). The most prevalent INH resistance mutation was S315T (78%) in the katG codon and the most common rifampicin resistance mutation was S531L (68%) in the rpoB codon. Among 13 specimens from TB suspects with negative sputum cultures, 7 had a positive MTBDRplus assay (3 with MDR-TB). The time to detection of MDR-TB was significantly less using the MTBDRplus assay (4.2 days) compared to the use of standard phenotypic tests (67.3 days with solid media and 21.6 days with broth-based media). Conclusions: Compared to conventional methods, the MTBDRplus assay had high accuracy and significantly reduced time to detection of MDR-TB in an area with high MDR-TB prevalence. The use of rapid molecular diagnostic tests for TB and drug resistance should increase the proportion of patients promptly placed on appropriate therapy.
Introduction
To identify patient characteristics associated with low serum 25-hydroxyvitamin D (25(OH)D) concentrations in the medical intensive care unit (ICU) and examine the relationship between serum 25(OH)D and the risk for hospital-acquired infections.
Methods
This is a prospective observational cohort of adult patients admitted to the medical ICU at an urban safety net teaching hospital in Atlanta, Georgia from November 1, 2011 through October 31, 2012 with an anticipated ICU stay ≥ 1 day. Phlebotomy for serum 25(OH)D measurement was performed on all patients within 5 days of ICU admission. Patients were followed for 30 days or until death or hospital discharge, whichever came first. Hospital-acquired infections were determined using standardized criteria from review of electronic medical record.
Results
Among the 314 patients analyzed, 178 (57%) had a low vitamin D at a serum 25(OH)D concentration < 15 ng/mL. The patient characteristics associated with low vitamin D included admission during winter months (28% vs. 18%, P = 0.04), higher PaO2/FiO2 (275 vs. 226 torr, P = 0.03) and a longer time from ICU admission to study phlebotomy (1.8 vs. 1.5 days, P = 0.02). A total of 36 (11%) patients were adjudicated as having a hospital-acquired infection and in multivariable analysis adjusting for gender, alcohol use, APACHE II score, time to study phlebotomy, ICU length of stay and net fluid balance, serum 25(OH)D levels < 15 ng/mL were not associated with risk for hospital-acquired infections (HR 0.85, 95% CI 0.40-1.80, P = 0.7).
Conclusions
In this prospective, observational cohort of adults admitted to a single-center medical ICU, we did not find a significant association between low 25(OH)D and the risk for hospital-acquired infections.
Setting: Georgia, a country with a high-burden of multi-drug-resistant tuberculosis (MDR-TB).
Objective: To determine the proportion of loss to follow-up (LFU) among MDR-TB patients treated nationwide from 2009 to 2011, and associated risk factors.
Design: Retrospective cohort study involving a review of the National Tuberculosis Programme electronic surveillance database. A Cox proportional hazards model was used to assess risk factors for time to LFU.
Results: Among 1593 patients, 458 (29%) were lost to follow-up. A total of 1240 MDR-TB patients were included in the final analysis (845 treatment success, 395 LFU). Over 40% of LFU occurred during the first 8 months of MDR-TB treatment; 40% of patients had not achieved culture conversion at the time of LFU. In multivariate analysis, the factors associated with LFU included male sex, illicit drug use, tobacco use, history of previous anti-tuberculosis treatment, site of TB disease, and place and year of initiating treatment.
Conclusion: LFU was high among MDR-TB patients in Georgia and posed a significant public health risk, as many were culture-positive at the time of LFU. A multi-pronged approach is needed to address the various patient- and treatment-related characteristics associated with LFU.