Objective—To assess phylogenetic relationships
among Mycobacterium bovis isolates by use of random
amplified polymorphic DNA polymerase chain
reaction (RAPD-PCR) fingerprinting and to relate genetic
profiles of isolates to epidemiologic characteristics.
Animals—400 cattle with tuberculosis.
Procedure—Mycobacterium bovis was isolated from
various organs of cattle slaughtered in 6 geographic
regions of Mexico. Most cattle were adult Holsteins
from large herds that did not participate in a tuberculosis
control program. Four random primers and 2
selected primers were used in RAPD-PCR fingerprinting
of 88 isolates. Pairwise genetic distance between
isolates was obtained and subjected to cluster analysis
with bootstrapping to test for levels of support.
Results—98 different fragments were obtained; there
was broad genetic diversity among isolates, and each
isolate had a unique RAPD-genotype, including those
originating from the same herd. Clustering by geographic
location, affected organ, or severity of lesion
was not detected. Linkage disequilibrium analysis suggested
that M bovis was highly clonal and that mutations
develop at a rapid rate among isolates.
Conclusions and Clinical Relevance—Use of RAPDPCR
could not differentiate M bovis isolates by epidemiologic
characteristics or identify common
sources of infection. (Am J Vet Res 2000;61:90–95)