Setting: Germany, 1995 to 2001.
Objective: To determine the genetic relationship of 451 multidrug-resistant (MDR) Mycobacterium tuberculosis strains from Germany and to identify strains of the Beijing genotype.
Design: All strains were analysed using IS6110 fingerprinting and a cluster analysis was performed. Clustering of isolates was used as a measure for recent transmission.
Results: Two hundred and fourteen of 433 strains (49.4%) with more than four IS6110 copies formed 46 fingerprint clusters comprising two to 32 patients. Transmission links based on classical epidemiological data could be established for 39 cases (18.2%) and in 14 clusters (30.4%), and included three cases of exogenous reinfection with MDR strains. One hundred and seventy-five strains (38.8%) were of the Beijing genotype with an increasing annual proportion from 19.2% in 1995 to 58.3% in 2001. About 70% of these patients had an indication of foreign birth, mainly the former Soviet Union.
Conclusion: Transmission of MDR strains seems to be contributing to the spread of MDR-TB in Germany, and exogenous reinfection with MDR strains must be considered as a possible cause of treatment failure. A high proportion of these MDR strains is probably carried over from the former Soviet Union, and strains of the Beijing genotype represent an increasing cause of MDR-TB in Germany.