Identification and comparison of Mycobacterium leprae genotypes in two geographical regions of Colombia

To evaluate and establish genomic strain typing markers suitable for the identification of transmission patterns of leprosy in different regions of Colombia.

Patients from Agua de Dios, Barranquilla and Cartagena cities and neighbouring towns were enrolled during 2006-2007. Slit skin smears or biopsies were obtained from newly detected untreated patients, and those undergoing multidrug therapy. DNA was extracted from the clinical samples and tested using 15 different short tandem repeat and three SNP polymorphic markers.

Differences or similarities between strain types from the northeast (n = 20) and central regions of Colombia (n = 18) were noted. The alleles at two loci, 27-5 and 12-5 were different in the M. leprae in the two regions. The other microsatellite loci may be useful for further intra-population differentiation. There was strong association of 27-5 and 12-5 alleles with the SNP types. The 4-5 combination of alleles was associated with SNP type 3, while the 5-4 combination was mostly associated with SNP type 1, 2 or 4. The SNP type 4 m. leprae isolates were seen in patients in the northeast, but not in the central part.