Rapid determination of molecular relatedness of isolates of human cytomegalovirus.

Molecular comparisons of isolates of human cytomegalovirus (CMV) with restriction enzyme digests have helped to identify patterns of CMV transmission. Current techniques, however, require extensive tissue culture passage of the virus, which limits use of these analyses. In this report, we describe a rapid, less-expensive, and equally sensitive method of comparing CMV genomes. This procedure, which we have called "junctional hybridization," uses the cloned junction fragments of CMV strain AD169 as probes that hybridize to CMV DNA restriction digests previously separated by electrophoresis and transferred to nitrocellulose filters. The procedure eliminates the need for tissue culture passage of virus beyond the primary isolation and can be used directly with DNA extracted from CMV-infected tissue. In all cases, junctional hybridization was as sensitive as currently used methods of restriction enzyme digestion analyses in identifying identical or different CMV isolates. Use of junctional hybridization should facilitate molecular analyses for study of the epidemiology of CMV infections.