Comparative analysis of M. tuberculosis drug susceptibility tests results in new multidrug-resistant tuberculosis cases and their confirmed contacts

<b>Background:</b> When drug susceptibility tests (DST) confirmation of drug resistance in newly identified tuberculosis (TB) patients is not possible, there is a serious problem when choosing the correct treatment regimen. Data on the drug resistance of the M. tuberculosis (MBT) source of infection can help in prescribing adequate treatment to contact patients without DST confirmed susceptibility MTB. <b>Aims:</b> To analyze the spectrum of drug resistance (DR) of M. tuberculosis (MBT) in newly diagnosed culture-positive TB-patients from contact with index case with confirmed multidrug-resistant tuberculosis (MDR -TB). <b>Methods:</b> 162 pairs “index case-contact” were included to the study. DST results of index cases with MDR-TB and their confirmed contacts were analyzed and compared. The DST results with isoniazid (H), rifampicin (R), fluoroquinolones (Fq), aminoglycosides and polypeptide (Amg) were analyzed. Relative Risk with 95% confidence interval were defined with Cochran-Mantel-Haenszel Test. <b>Results:</b> The data on the comparability of MBT DR for index cases and their contacts were following: H- 1.02 (95% CI 0.97-1.08); R- 1.04 (95% CI 1.00—1.09); Fq – 1.15 (95% CI 0.80-1.67); Amg – 0.81 (95% CI 0.56-1.17). The high frequency of coincidence of the DR MBT for index cases and their contacts were defined. <b>Conclusion:</b> When prescribing a chemotherapy regimen for patients without confirmed MTB DR from MDR-TB contact, it is important to consider the index cases DST results of the index case.