Pulmonary function and respiratory health after successful treatment of drug-resistant tuberculosis.

BACKGROUND: Post-treatment morbidity among subjects with drug-resistant tuberculosis (DR-TB) is unclear. METHODS: This was a cross-sectional study of patients from Tbilisi, Georgia with cavitary DR-TB and an outcome of cure. Participants had a chest X-ray (CXR), St. George Respiratory Quality (SGRQ) survey, and pulmonary function tests (PFTs) performed. Correlations between SGRQ and PFT results and factors associated with pulmonary impairment were examined. RESULTS: Among 58 subjects (median age 31 years), 40% used tobacco, 59% had prior TB, and 47% underwent adjunctive surgical resection. The median follow-up time was 41 months. Follow-up CXR revealed fibrosis in 30 subjects (52%) and bronchiectasis in seven (12%). The median forced expiratory volume (FEV1)/forced vital capacity (FVC) ratio was 0.72, with 24 subjects (41%) having a ratio of ≤0.70. Significant correlations existed between PFT measures and overall and component SGRQ scores. In linear regression, age, prior TB, and CXR fibrosis or bronchiectasis were significantly associated with decreased pulmonary function. Adjunctive surgery was significantly associated with a higher percent predicted FEV1 and FVC. CONCLUSIONS: A high proportion of DR-TB subjects had residual pulmonary impairment, particularly with recurrent TB and severe radiological disease. The association of surgical resection with improved lung function deserves further study. PFTs and SGRQ may both be useful to evaluate lung health.

High utility of contact investigation for latent and active tuberculosis case detection among the contacts: a retrospective cohort study in Tbilisi, Georgia, 2010-2011.

SETTING: The study was conducted at the National Center for Tuberculosis and Lung Diseases (NCTBLD) in Tbilisi, Georgia. OBJECTIVE: To assess the utility of contact investigation for tuberculosis (TB) case detection. We also assessed the prevalence and risk factors for active TB disease and latent TB infection (LTBI) among contacts of active pulmonary TB cases. DESIGN: A retrospective cohort study was conducted among the contacts of active pulmonary TB cases registered in 2010-2011 at the NCTBLD in Tbilisi, Georgia. Contacts of active TB patients were investigated according to an "invitation model": they were referred to the NCTBLD by the index case; were queried about clinical symptoms suggestive of active TB disease; tuberculin skin testing and chest radiographs were performed. Demographic, laboratory, and clinical data of TB patients and their contacts were abstracted from existing records up to February 2013. RESULTS: 869 contacts of 396 index cases were enrolled in the study; a median of 2 contacts were referred per index case. Among the 869 contacts, 47 (5.4%) were found to have or developed active TB disease: 30 (63.8%) were diagnosed with TB during the baseline period (co-prevalent cases) and 17 (36.2%) developed active TB disease during the follow-up period (mean follow up of 21 months) (incident TB cases). The incidence rate of active TB disease among contacts was 1126.0 per 100,000 person years (95% CI 655.7-1802.0 per 100,000 person-years). Among the 402 contacts who had a tuberculin skin test (TST) performed, 52.7% (95% CI 47.7-57.7%) had LTBI. CONCLUSIONS: A high prevalence of LTBI and active TB disease was found among the contacts of TB cases in Tbilisi, Georgia. Our findings demonstrated that an "invitation" model of contact investigation was an effective method of case detection. Therefore, contact investigation should be scaled up in Georgia.

Monitoring therapeutic efficacy by real-time detection of Mycobacterium tuberculosis mRNA in sputum.

BACKGROUND: Current laboratory methods for monitoring the response to therapy for tuberculosis (TB) rely on mycobacterial culture. Their clinical usefulness is therefore limited by the slow growth rate of Mycobacterium tuberculosis. Rapid methods to reliably quantify the response to anti-TB drugs are desirable. METHODS: We developed 2 real-time PCR assays that use hydrolysis probes to target DNA of the IS6110 insertion element and mRNA for antigen 85B. The nucleic acids are extracted directly from concentrated sputum samples decontaminated with sodium hydroxide and N-acetyl-L-cysteine. We prospectively compared these assays with results obtained by sputum mycobacterial culture for patients receiving anti-TB therapy. RESULTS: Sixty-five patients with newly diagnosed TB and receiving a standardized first-line anti-TB drug regimen were evaluated at week 2 and at months 1, 2, and 4 after therapy initiation. Both the DNA PCR assay (98.5% positive) and the mRNA reverse-transcription PCR (RT-PCR) assay (95.4% positive) were better than standard Ziehl-Neelsen staining techniques (83.1%) for detecting M. tuberculosis in culture-positive sputum samples. The overall agreement between culture and mRNA RT-PCR results for all 286 sputum samples was 87.1%, and compared with culture, the mRNA RT-PCR assay's diagnostic sensitivity and specificity were 85.2% and 88.6%, respectively. For monitoring efficacy of therapy, mRNA RT-PCR results paralleled those of culture at the follow-up time points. CONCLUSIONS: The continued presence of viable M. tuberculosis according to culture and results obtained by RT-PCR analysis of antigen 85B mRNA correlated clinically with resistance to anti-TB drugs, whereas the DNA PCR assay showed a high false-positive rate. This mRNA RT-PCR assay may allow rapid monitoring of the response to anti-TB therapy.