Limited genetic diversity of Brucella spp.

Multilocus enzyme electrophoresis (MLEE) of 99 Brucella isolates, including the type strains from all recognized species, revealed a very limited gene tic diversity and supports the proposal of a monospecific genus. In MLEE-de rived dendrograms, Brucella abortus and a marine Brucella sp. grouped into a single electrophoretic type related to Brucella neotomae and Brucella ovi s, Brucella suis and Brucella canis formed another fluster linked to Brucel la melitensis and related to Rhizobium tropici. The Brucella strains tested that were representatives of the six electrophoretic types had the same rR NA gene restriction fragment length polymorphism patterns and identical rib otypes, All 99 isolates had similar chromosome profiles as revealed by the Eckhardt procedure.