Detection of Corynebacterium kutscheri in animal tissues by DNA-DNA hybridization.

Corynebacterium kutscheri, a pathogen of experimental rats and mice, is difficult to detect in the early stages of infection. A diagnostic assay was developed to reveal the organism in tissues of asymptomatic, infected animals. Three fragments of DNA specific to C. kutscheri were isolated, radiolabeled with 32P, and used in DNA-DNA hybridization assays with blots of impression smears of animal tissues on membrane filters. The C. kutscheri probes did not cross-hybridize with 15 DNA isolates from nonpathogenic corynebacteria. The method described is more rapid and more specific than conventional immunological and culture procedures used to detect C. kutscheri; the organism was detected in tissues of animals infected for only 1 week.