Comparison of culture, polymerase chain reaction, and fluorescent in situ hybridization for detection of Brachyspira hyodysenteriae and "Brachyspira hampsonii " in pig feces

Swine dysentery is characterized by mucohemorrhagic diarrhea and can occur following infection by Brachyspira hyodysenteriae or “Brachyspira hampsonii ”. A definitive diagnosis is often based on the isolation of strongly beta-hemolytic spirochetes from selective culture or by the application of species-specific polymerase chain reaction (PCR) assays directly to feces. While culture is highly sensitive, it typically requires 6 or more days to complete, and PCR, although rapid, can be limited by fecal inhibition. Fluorescent in situ hybridization (FISH) has been described in formalin-fixed tissues; however, completion requires approximately 2 days. Because of the time constraints of available assays, a same-day FISH assay was developed to detect B. hyodysenteriae and “B. hampsonii ” in pig feces using previously described oligonucleotide probes Hyo1210 and Hamp1210 for B. hyodysenteriae and “B. hampsonii”, respectively. In situ hybridization was simultaneously compared with culture and PCR on feces spiked w...