Natural habitats of Corynebacterium kutscheri in subclinically infected ICGN and DBA/2 strains of mice.

Subclinically infected mice of ICGN and DBA/2 strains housed in a conventionally managed colony were examined to determine natural habitats of Corynebacterium kutscheri. At 5, 7, 9, 12 and 13 months after initial isolation of the organism from oral cavity and cecal contents of five ICGN mice, attempts were made to isolate C. kutscheri from 19 sites using a new selective medium, furazolidone-nalidixic acid-colimycin agar. From the initial survey to 13 months, C. kutscheri was isolated from 27 of 29 ICGN mice (93.1%) and 9 of 10 DBA/2 mice (90%). In contrast, antibody against C. kutscheri was detected in only 3 of 29 ICGN mice (10.3%). None of the mice manifested distinct clinical signs of infection, and only 1 ICGN mouse had macroscopic lesions such as hepatic abscess and large spleen. In 21 ICGN and 9 DBA/2 mice that harbored the organism without macroscopic lesions, the organisms were most frequently isolated from the oral cavity (ICGN:100%, DBA/2:66.7%), cecum (ICGN:95.2%, DBA/2:100%), and colon and rectum (ICGN:95.2%, DBA/2:100%). Remarkable differences between the two mouse strains were observed in colonization of the nasal cavity (ICGN:85.7%, DBA/2:0%) and trachea (ICGN:71.4%, DBA/2:33.3%). In mice of both strains, the organisms rarely colonized the lung, liver, and kidney. Mean numbers of organisms in the cecum, and colon and rectum ranged from 10(4.1) to 10(4.6) colony-forming units/g and were significantly higher in comparison with those in the small intestine (P < 0.01, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)