FIG 7.

PCR of C. perfringens colonies isolated from the coinfection experiment. Representative PCR electrophoresis images of recovered colonies tested for nanI by PCR using the primers nanIKOF and nanIKOR to distinguish the nanI null mutant (1,367 bp) from the nanI-complemented (467 bp) strain are shown. Clindamycin-pretreated mice were orally challenged with equivalent numbers of the F4969 nanI null mutant and the nanI-complemented strains. Representative numbers of C. perfringens colonies from intestinal mucosal scrapings were tested by PCR on days 1 and 3. The numbers on the left are molecular size markers (in base pairs). S.I., small intestine.