Molecular epidemioloic analysis of Mycobacterium bovis isolates from Mexico

Objective-To assess phylogenetic relationships among Mycobacterium bovis is olates by use of random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) fingerprinting and to relate genetic profiles of isolates to ep idemiologic characteristics. Animals-400 cattle with tuberculosis. Procedure-Mycobacterium bovis was isolated from various organs of cattle sl aughtered in 6 geographic regions of Mexico. Most cattle were adult Holstei ns from large herds that did not participate in a tuberculosis control prog ram. Four random primers and 2 selected primers were used in RAPD-PCR finge rprinting of 88 isolates. Pairwise genetic distance between isolates was ob tained and subjected to cluster analysis with bootstrapping to test for lev els of support. Results-98 different fragments were obtained; there was broad genetic diver sity among isolates, and each isolate had a unique RAPD-genotype, including those originating from the same herd. Clustering by geographic location, a ffected organ, or severity of lesion was not detected. linkage disequilibri um analysis suggested that M bovis was highly clonal and that mutations dev elop at a rapid rate among isolates. Conclusions and Clinical Relevance-Use of RAPD-PCR could not differentiate M bovis isolates by epidemiologic characteristics or identify common source s of infection.