prevalence of mycobacterium tuberculosis in the samples referred to the tuberculosis research laboratory in mashhad ghaem hospital during 2005-2006

background: tuberculosis continues to be a serious public health problem causing nearly three million deaths per year all over the world. despite major improvement in diagnosis, it is not possible to control the disease in the absence of surveillance treatment, and follow-up programs. objectives: this research was designed to study the frequency of mycobacterium tuberculosis among specimens referred to the tuberculosis research laboratory in qaem hospital, mashhad, north- east of iran in 2005-2006. materials and methods : 3207 samples (1331 sputum, 1209 bronchial lavage, 69 ascitis aspirates, 52 urine samples, 30 csf samples, 25 joint aspirates and 15 wound secretions) were cultured according to standard procedure and examined microscopi- cally using ziehl neelsen staining method. results: 536 samples (16.7%) recognized as positive for mycobacterium tuberculosis . (bronchial lavage 18.6%, sputum 17%, gastric lavage 13.3%, csf 10%, ascitis aspirates 7.2%, wound 6.25%, pleural aspiration 4.5%). no mycobacterium tubercu- losis was found in urine samples and joint aspirates. conclusion: considering reported prevalence of 13 cases per 100,000 in the iranian population, these results are acceptable but more preventive measures should be sought for controlling tb.