Usefulness of restriction fragment length polymorphism and spoligotyping for epidemiological studies of Mycobacterium bovis in Madagascar: description of new genotypes.

Tuberculosis is highly prevalent in cattle in Madagascar. An epidemiological study based on genotyping of Mycobacterium bovis and its transmission to humans was carried out. The restriction fragment length polymorphism (IS6110 and DR markers) and spoligotyping were used to assess the genetic diversity of strains from different regions of Madagascar. One of these strains was isolated from goat, the other strains were isolated from zebu cattle. Nine IS6110 profiles, 20 DR profiles and 12 spoligotypes were obtained. About 90% of all isolates gave a single IS6110 band at about 1.8 kb. Most strains had the same spoligotype. M. bovis strains commonly lack spacers 39-43, and all Malagasy strains also lacked spacers 3-5, 8-10 and 16. This pattern has not been reported elsewhere. DR was the most discriminatory of the three markers. The patterns obtained with the three markers were combined to identify 34 different genotypes, one of which was found in 35% of the strains. No region-specific M. bovis genotype was identified, but the genotyping of 18 M. bovis strains isolated from patients showed that the human and bovine strains were identical, suggesting possible human contamination from zebu cattle.