[Tuberculosis in Europe and Poland--new molecular families and new resistance patterns].

At present despite methods of fast recognition of the disease and efficient antituberculosis drugs not only we cannot contain the epidemic but we can see an increase in new cases of tuberculosis including its drug resistant variety. Causes of aggravation of the situation are varied and ought to be examined separately in case of any particular region. One of the major ones are bad programmes of fighting against the disease or their inadequate realization, ignoring a problem of tuberculosis in developed countries, lack of money for treatment in developing countries and coincidence with HIV virus. Among the mentioned factors the phenomenon of drug resistance is considered one of most important reasons of expansion of tuberculosis in the modern world. In epidemiological investigations it is important to determine, apart from drug resistance patterns, what molecular families strains belong to. This allows us to track their transmission routes. Genotyping has given us knowledge of the threats connected with transmission of the infection and made it possible to identify a risk factor which is the cause of MDR (multidrug-resistant), XDR (extensively drug-resistant tuberculosis) strains dissemination as well as strains representing new molecular families. Results of some analyses proved to be surprising. For instance high proportion of genetically similar strains has been shown in countries of low incidence. It proves higher than expected transmission in societies of high economic standard. Analyses of DNA of mycobacteria led to distinguishing several genetic families among which M. tuberculosis Beijing is one of most important.