Mycobacterium bovis subsp caprae caused one-third of human M-bovis-associated tuberculosis cases reported in Germany between 1999 and 2001

The prevalence of the Mycobacterium bovis subsp. caprae and M. bovis subsp. bovis among German tuberculosis cases caused by the bovine tubercle bacillus from 1999 to 2001 was determined. Isolates from 166 patients living in Germany and 10 animals were analyzed by conventional laboratory procedures, spolligotyping, and partly by PCR-restriction fragment length polymorphism analysis of the gyrB gene. By spolligotyping, 55 of 176 isolates (31%) could be identified as M. bovis subsp. caprae, and 121 (69%) were confirmed as M. bovis subsp. bovis. In general, a low variability of spoligotypes with 59 distinct patterns and a cluster rate of 77% (136 isolates/19 clusters) was determined. About half of all isolates were grouped in the three main clusters with 29, 30, and 35 isolates, respectively. Differences in age and gender between the patient groups infected with M. bovis subsp. bovis and M. bovis subsp. caprae did not reach statistical significance. However, marked differences in the geographical prevalence of M. bovis subsp. caprae were observed, ranging from fewer than 10% of all M. bovis isolates in the north up to more than 80% of isolates in the south of Germany. In conclusion, M. bovis subsp. caprae accounts for a high ratio of human M. bovis-associated tuberculosis cases in Germany and was more frequently found in the southern part.