Abstract
Epidemiologic diagnosis of nosocomial tuberculosis implies identification of secondary (cross-) infection cases in TB patients during their treatment (staying) in TB medical facilities, their causes and risk-factors. TB facilities nosocomial infection epidemiologic diagnosis system organization is still not developed as on scientifically validated methodic recommendations level, as well as on existing practices. Russian and foreign studies had demonstrated that treatment in "in-patient" TB hospitals occurred one of the causes (risk factors) of the secondary TB infection. Reported secondary infection molecular-genetically validated cases frequency varies in different studies as 1,09- 15,39% (5,26%, averagely). In MDR-TB wards -16,9%-36,99% (averagely 25,2%). Mycobacteria identified as causing agents of nosocamial infection episodes were characterized as highly virulent and with high clustering level.