Molecular Monitoring of the Main Changes in Bacterial Floral Diversity in the Gastrointestinal Tract of a Thoroughbred Foal with Catarrhal Enteritis by Using PCR-DGGE

In this study, the main changes in bacterial floral diversity in the gastrointestinal tract of a Thoroughbred foal were monitored by using polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The foal died of catarrhal enteritis of the cecum and large colon. Diarrheal feces and gastrointestinal contents were compared with normal feces. The closest relatives of the bacterium in the samples were Lactobacillus johnsonii (100% similarity), uncultured Bacteroides sp. (92.5% similarity), Bacteroides fragilis (96.3% similarity), and Enterococcus faecium/Enterococcus durans (100% similarity); these were detected by PCR-DGGE using a universal primer set. Monitoring revealed that the numbers of Escherichia coli/Shigella sonnei (97.9% similarity) were significantly higher in the diarrheal feces. Thus, PCR-DGGE is a useful tool for monitoring the main changes in bacterial floral diversity occurring in the gastrointestinal tracts of Thoroughbreds.