Studying a new species of bacteria that are making pigs sick

Swine dysentery is an economically significant disease affecting pigs. It is characterized by the presence of variable amounts of blood and/or mucus in wet to runny diarrhea. Without appropriate intervention strategies, it can result in elevated mortality and decreased feed efficiency and growth rates. A new species of spiral-shaped bacteria called “Brachyspira hampsonii” was identified in 2009 in North American pigs with bloody diarrhea. The characteristics that distinguish this new species from related bacteria need to be identified so that diagnostic labs can detect and identify “B. hampsonii” in samples from pig farms, providing farmers and veterinarians with valuable information as they work to control or eliminate disease.

We analysed isolates from sick pigs on different farms across Western Canada for analysis to determine how much variation there was in their characteristics and what traits they all have in common. We found that the Western Canadian isolates have variable traits, some of which have not previously been reported. These variable traits are not useful for distinguishing “B. hampsonii” from other closely related species. We also found that the size and shape of “B. hampsonii” are similar to other Brachyspira that cause disease in pigs.

Our results show that tests based on the physical and biochemical properties of “B. hampsonii” are not helpful in distinguishing this novel species, and that DNA sequencing of bacterial genes is a more useful approach. These findings will be useful to veterinarians and diagnostic laboratories in their work with pig farmers to control or eliminate disease caused by “B. hampsonii”.

Read the full paper — Characterization of “Brachyspira hampsonii” clades I and II isolated from commercial swine in Western Canada
by Jason Byron D.S. Perez, Joseph E. Rubin, Champika Fernando, John C.S. Harding and Janet E. Hill on the FACETS website.