The efficacy of the meat inspection procedures implemented for the detection of tuberculous cattle was evaluated by testing for bovine tuberculosis in 751 animals. The study involved routine inspection at slaughter, collection of tissues for detailed examination in the laboratory, and bacteriological investigation to identify Mycobacterium bovis. Of the 751 carcasses examined, 34 (4.5%) were found to have tuberculous lesions. Routine abattoir inspection detected only 29.4% of the carcasses with visible lesions. Eighty-four percent of the tuberculous lesions were found in the lungs and thoracic lymph nodes, 11.5% in the lymph nodes of the head, and the remaining 4.5% in the mesenteric and other lymph nodes of the carcasses. In addition, M. bovis was isolated from a carcass that presented no gross tuberculosis lesions. The low sensitivity of routine abattoir inspection demonstrates that existing necropsy procedures should be improved.

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Early detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is of primary importance for both patient management and infection control. Optimal methods for identifying drug-resistant Mycobacterium tuberculosis in a timely and affordable way in resource-limited settings are not yet available. This study prospectively evaluated a low-technology but rapid drug susceptibility testing method, the microscopic observation drug susceptibility assay (MODS), in the concurrent detection of M. tuberculosis and its susceptibilities to isoniazid and rifampin (two drugs defining multidrug-resistant M. tuberculosis) directly from sputum specimens. Sputum samples were collected from 262 smear-positive TB patients in Addis Ababa, Ethiopia. To undertake MODS, 100 l of decontaminated samples was inoculated into a 24-well plate containing 1 ml of 7H9 broth with and without appropriate drugs. The assay uses an inverted-light microscope to detect characteristic mycobacterial growth in liquid culture. Of 262 smear-positive patients, MODS detected 254 (96.9%) and culture in Löwenstein-Jensen medium detected 247 (94.3%) (P ‫؍‬ 0.016). For the 247 cultures, the sensitivity, specificity, and accuracy of MODS for detecting MDR-TB were 92.0, 99.5, and 98.8%, respectively, using the method of proportion as a reference (concordance, 98.8%; kappa value, 0.932). Results for MODS were obtained in a median time of 9 days. MODS is an optimal alternative method for identifying MDR-TB in a timely and affordable way in resource-limited settings.Tuberculosis (TB), once in decline, is now experiencing a resurgence fueled in part by the human immunodeficiency virus (HIV)/AIDS pandemic. Multidrug-resistant Mycobacterium tuberculosis (MDR-TB), defined as resistant to at least isoniazid (INH) and rifampin (RIF), is complicating TB control efforts in several low-and middle-income countries. A critical mass of resistance seen in high-burden countries has great potential not only to halt the progress of TB control but also to reverse it (34). Implementation of additional strategies, such as reducing transmission by detecting cases earlier and improving infection control in settings with shared-air spaces, is urgently needed (29). Optimal methods for identifying drugresistant M. tuberculosis in a timely and affordable way in resource-limited settings are not yet available. The currently available drug susceptibility testing (DST) methods with solid media are inexpensive but slow and laborious and cannot meet such a demand. Liquid automated commercial systems (13,14,20,28), such as the BACTEC MGIT 960 (Becton Dickinson, Sparks, MD), are rapid but require heavy, expensive equipment, have high running costs, and are technically complex. Molecular genetic methods (16,17,22,29) are fast but too expensive and require well-trained manpower in order to be used in resource-poor settings. In addition, not all mutations conferring resistance to anti-TB drugs are known. Several lowtechnology methods (1,2,8,10,26,30,32) are also available. Most are indirect D...

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Drug resistance tuberculosis threatens the National Tuberculosis Control Programme in several countries. A crosssectional study was conducted during the period between November 2004 and October 2005 to determine drug susceptibility pattern of Mycobacterium tuberculosis (n=37) isolated from smear negative pulmonary tuberculosis patients (PTB), and to access whether these patients are at risk of harbouring drug resistant strains. Of the 37 M. tuberculosis isolates, 21/37 (29.8%) showed resistance to any of the drugs tested. No MDR-TB strains (resistant to INH and Rifampicin) were observed in this study. No statistically significant differences appeared in the frequency and pattern of resistance between isolates from smear positive and negative cases. This study provides potentially valuable information of the value of culture in the diagnosis of smear-negative cases to certain extent in untreated newly diagnosed PTB patients. Smear negative TB patients can harbor drug resistant strains like their smear positive counterparts.