Epidemiologic characteristics of MDR/XDR tuberculosis in Montenegro, from 2005 to 2018

Background: In the conditions of declining rate of drug-resistant tuberculosis and high success rate of treatment of these cases, occurrence of MDR/XDR-TB due to complexity of its treatment remains the main problem in controlling this disease in Montenegro. Methods and materials: Data on multidrug-resistant (MDR), extensively drug-resistant (XDR) and drug-susceptible (DSTB) cases for the referring period were obtained from National Tuberculosis Center in Montenegro. Case definitions and received treatment were according to WHO recommendations. Clinical characteristics and treatment outcomes of DSTB, MDR and XDR-TB patients were analyzed. Results: Rate of occurrence of drug-resistant tuberculosis shows slow but continuous decline in Montenegro for the past fourteen years, with the yearly rate of 1.1% from 27 to 13/100,000 population. Success rate is high, 80–92%. For the same period, minor part (0–1%) of newly diagnosed patients had MDR/TB while XDR/TB has not been diagnosed with the new cases, which is suggesting that the transmission of drug-resistant Mtb in general population is very small. Previously treated patients had from 11 to 40% MDR/TB depending on the year and 14 to 46% XDR/TB. Little more than third (38%) of MDR isolate of our cases were resistant to all first line medication and XDR/TB isolates were resistant to more than 6–7 anti-tuberculosis medications. This explains in part bad effectiveness of treatment in drug-resistant cases. Half of all MDR/TB cases (43%) failed in treatment. The highest number of drug-resistant cases (75%) was registered in the first half of the control period complete therapy regime and most of them had unsuccessful treatment. The reason was the failure to continuously provide complete therapy regime for these patients. Supporting this was a successful treatment of two cases of XDR/TB in another center out of country in order to provide the full and complete treatment regime. Conclusion: High success treatment rate of drug-resistant tuberculosis decreases the possibility of occurrence and transmission of resistant Mtb layers in the population. Efficient and available medication in treatment of drug-resistant tuberculosis are a pre-condition of its control.