[Microbiological diagnosis of tuberculosis in Serbia in the period 2001-2003].

Introduction: The National tuberculosis Reference Laboratory (NTRL) and the National TB Laboratory Network in Serbia, provided data on drug susceptibility profiles of M. tuberculosis, incidence of TB among laboratory workers and on protective measures.

Material And Methods: The TB laboratory network in Serbia comprises 46 laboratories. 11 laboratories perform acid fast microscopy only, 24 perform microscopic and culture examinations, and complete identification and drug susceptibility testing (DST) is performed in 11 laboratories. Protective measures for laboratory workers are mostly inadequate. Four cases of occupational TB were reported over the study period.

Results: DST was performed in 61.8% to 62.8% of bacteriologically proven TB cases. Isolates of M. tuberculosis strains showing drug-resistance ranged from 7.9% to 8.9%, while multidrug resistant (MDR) isolates varied from 2.2% to 2.5%. In order to determine the accuracy of DST in 6 local laboratories, NTRL carried out a quality assurance program for DST. Four laboratories reached 100% agreement with NTRL for rifampicin. At least 90% agreement with NTRL for isoniazid was achieved in three tested laboratories.

Conclusion: A relatively low and stable rates of drug-resistant and MDR TB in our study indicate that the situation in Serbia is still satisfactory. However, a reliable surveillance of drug-resistant TB in the region requires routine DST of all patients with culture confirmed TB. This is one of the goals included in the new National TB Program. In summary, all laboratories in Serbia should be included in the quality assurance program and their number should be reduced in accordance with the annual number of analyses performed, geographical location and results of proficiency testing.