[show abstract][hide abstract] ABSTRACT: Background. There were 1.45 million deaths from tuberculosis (TB) in 2011. A substantial proportion of active pulmonary TB cases in countries where tuberculosis, human immunodeficiency virus (HIV) infection, and AIDS are highly endemic remain undiagnosed because of the reliance on sputum-smear microscopy. This study evaluated the performance of the Xpert MTB/RIF assay at a tertiary care referral center in Zambia, a country where the burden of TB and HIV infection is high. Methods. A total of 881 adult inpatients admitted to University Teaching Hospital in Lusaka who were able to produce sputum were enrolled and analyzed in the study, irrespective of admission diagnosis. Sputum specimens were analyzed by fluorescence smear microscopy, the Xpert MTB/RIF assay, mycobacterial growth indicator tube (MGIT) culture, and MGIT drug-susceptibility testing. The sensitivity and specificity of the Xpert MTB/RIF assay were evaluated using culture as the gold standard. Results. Culture-confirmed TB was found in 201 of 881 patients (22.8%). The specificity of the Xpert MTB/RIF assay was 95.0% (95% confidence interval [CI], 92.4%-96.8%), and the sensitivity was 86.1% (95% CI, 80.3%-90.4%). In sputum smear-negative, culture-positive cases, the assay was 74.7% sensitive (95% CI, 64.6%-82.8%), identifying 71 additional TB cases that were not detected by smear microscopy. A total of 18 of 111 patients with TB who were tested (16.2%) had multidrug-resistant (MDR) TB. The sensitivity and specificity of the Xpert MTB/RIF assay for detecting culture-confirmed, rifampicin-resistant TB was 81.3% (95% CI, 53.7%-95.0%) and 97.5% (95% CI, 90.4%-99.6%), respectively. Conclusions. The Xpert MTB/RIF assay performs better than smear microscopy in an inpatient setting in a country where TB and HIV infection are highly endemic. Assessment of its usefulness and cost-effectiveness for increased detection of TB cases missed by sputum smear and for concomitant screening for MDR TB among adult inpatients attending tertiary care referral centers in other countries with a high burden of TB and HIV infection is warranted.
[show abstract][hide abstract] ABSTRACT: Background: A high burden of tuberculosis (TB) occurs in sub-Saharan African countries and many cases of active TB and drug-resistant TB remain undiagnosed. Tertiary care hospitals provide an opportunity to study TB co-morbidity with non-communicable and other communicable diseases (NCDs/CDs). We evaluated the burden of undiagnosed pulmonary TB and multi-drug resistant TB in adult inpatients, regardless of their primary admission diagnosis, in a tertiary referral centre. Methodology/Principal Findings: In this prospective study, newly admitted adult inpatients able to produce sputum at the University Teaching Hospital, Lusaka, Zambia, were screened for pulmonary TB using fluorescent smear microscopy and automated liquid culture. The burden of pulmonary TB, unsuspected TB, TB co-morbidity with NCDs and CDs was determined. Sputum was analysed from 900 inpatients (70.6% HIV infected) 277 (30.8%) non-TB suspects, 286 (31.8%) TB suspects and 337 (37.4%) were already receiving TB treatment. 202/900 (22.4%) of patients had culture confirmed TB. TB co-morbidity was detected in 20/275 (7.3%) NCD patients, significantly associated with diabetes (P = 0.006, OR 6.571, 95%CI: 1.706–25.3). 27/202 (13.4%) TB cases were unsuspected. There were 18 confirmed cases of MDR-TB, 5 of which were unsuspected. Conclusions/Significance: A large burden of unsuspected pulmonary TB co-morbidity exists in inpatients with NCDs and other CDs. Pro-active sputum screening of all inpatients in tertiary referral centres in high TB endemic countries is recommended. The scale of the problem of undiagnosed MDR-TB in inpatients requires further study. Copyright: ß 2012 Bates et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: AZ, MH, JOG and MB acknowledge support from the European Union and the European and Developing Countries Clinical Trials Partnership (EDCTP).