MOLECULAR EPIDEMIOLOGY OF CRYPTOCOCCUS-NEOFORMANS IN BRAZIL AND THE UNITED-STATES - EVIDENCE FOR BOTH LOCAL GENETIC-DIFFERENCES AND A GLOBAL CLONAL POPULATION-STRUCTURE

Little is known about the global molecular epidemiology of the human p athogenic fungus Cryptococcus neoformans. We studied 51 clinical and e nvironmental (pigeon excreta) isolates from two cities in Brazil (Belo Horizonte and Rio de Janeiro) by analyzing their carbon assimilation patterns, electrophoretic karyotypes, restriction fragment length poly morphisms (RFLPs) with the C, neoformans repetitive element-1 (CNRE-1) , and URA5 Sequences, Results were compared to those previously obtain ed for isolates from New York City by the same DNA typing methods, Com puter-assisted analysis of RFLPs and contour-clamped homogeneous elect rophoresis (CHEF) patterns and URA5 sequences was performed to generat e dendrograms. Some environmental and clinical isolates were found to be indistinguishable by CHEF, CNRE-1 RFLP, and URA5 sequence analyses, Similarly, some isolates from Rio de Janeiro and Belo Horizonte were indistinguishable by the three DNA typing techniques, Overall, Brazili an isolates appeared to be less heterogeneous by DNA analysis than iso lates from other regions, Several Brazilian isolates were highly relat ed to New York City isolates, Phylogenetic analysis of the sequences o btained for the Brazilian isolates and those obtained for New York Cit y isolates was congruent with the dendrogram generated from the CNRE-1 RFLP data, In summary our results indicate (i) that the discriminator y power of the DNA typing method differs for Brazilian and New York Ci ty strains, with the order being CNRE-1 RFLP analysis > URA5 sequence analysis > CHEF analysis and CHEF analysis > URA5 sequence analysis > CNRE-1 RFLP analysis, respectively; (ii) that there are differences in local genetic diversity for Brazilian and New York City isolates; (ii i) that there is additional evidence linking clinical isolates to thos e in pigeon excreta; and (iv) that Some isolates from Brazil and New Y ork City are closely related, consistent with the global dispersal of certain pathogenic strains.