Introduction: Tuberculosis (TB) is a curable disease and its spread can be prevented by using appropriate diagnostic methods and effective treatment. The obstacle to the rapid eradication of the disease from a population may be strains resistant to essential and most effective antibiotics. In many places in the world MDR, pre-XDR and XDR-TB was reported. These forms of TB do not respond to the standard six-month treatment with first-line anti-TB drugs and the therapy should be conducted two years or more with drugs that are less potent, more toxic and much more expensive.
Material and methods: This study included MDR-TB strains isolated from 297 patients in 2000-2009. To determine the XDR-TB population structure, the 19 isolates were genotyped by spoligotyping and MIRU-VNTR (mycobacterial interspersed repetitive units-variable number of tandem repeats) method.
Results: Among 297 MDR-TB cases, 36 (12.1%) were pre-extensively drug-resistant (pre-XDR), 19 (6.4%) were XDR and 1 (0.3%) was pre-totally drug-resistant (pre-TDR). Four of the 19 XDR isolates exhibit a unique spoligopattern, while the rest 15 belonged to one of 5 clusters. The MIRU-VNTR analysis reduced the number of clustered isolates to 11.
Conclusions: The study documented the emergence of pre-extensively and extensively drug-resistant tuberculosis in Poland among patients with multidrug-resistant TB. Genotyping methods showed clonal similarity among XDR strains and may suggest the possible transmission among patients with newly diagnosed and with recurrent TB.