Resistance of Mycobacterium tuberculosis isolates in different populations in Greece during 1993–2002

OBJECTIVE: To document the prevalence of resistance of Mycobacterium tuberculosis to isoniazid (INH), rifampicin (RMP) and both combined (multidrug resistance [MDR]) in Greece from 1993 to 2002.

DESIGN: We studied a single sputum sample per patient from 4108 patients referred to the Greek National Referral Centre for Mycobacteria. Patients were divided into native Greeks, immigrants and repatriated Greeks originating from the former Soviet Union. Prior treatment status was not recorded.

RESULTS: A statistically significant increase in resistance to INH and RMP and MDR was noted comparing the years 1993–1997 to 1998–2002 (P < 0.0001). Resistance to INH and RMP and MDR rose from 5.6% to 7.71%, from 1.57% to 4.49% and from 1.23% to 3.98%, respectively, among native Greeks and from 23.63% to 32.91%, from 6.36% to 15.19% and from 6.36% to 13.92% among repatriated Greeks. Smaller changes were seen among immigrants (from 15.43% to 9.57% for INH, from 5.51% to 6.12% for RMP and from 5.71% to 5.32% for MDR).

CONCLUSION: We documented an increase in M. tuberculosis resistance to INH and RMP, and MDR. This was mainly limited to native and repatriated Greeks. Although this is likely the result of immigration and of mismanagement of index cases in Greece, molecular methods are needed to better describe the situation.