Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/1995
Publication Date: N/A
Citation: Interpretive Summary: In these studies, the characteristics of a bacterium that causes the disease known as "spirochetal diarrhea" were determined. Characteristics included DNA properties, sugars used for growth, waste products, antibiotic sensitivities. We named the organism "Serpulina pilosicoli". The name Serpulina indicates this bacterium is related to Serpulina hyodysenteriae, the etiologic agent of swine dysentery. The name pilosicoli means "of a hairy colon", and refers to the observation that cells of this bacterium attach by one end to intestinal cells in the colon and cecum and give the appearance of a "hairy covering" over these tissues. This spirochete causes diarrhea in postweaning and adult swine and has recently been isolated from humans with diarrhea. This spirochete may be the cause of intestinal diseases diagnosed with unknown etiology. Naming and characterizing this bacterium were important so that it can be recognized in veterinary diagnostic labs and hospital labs around the world and its incidence determined. The research has significance for swine producers, clinical diagnosticians, veterinarians, and animal health product companies.
Technical Abstract: Phenotypic and genetic traits of porcine intestinal spirochete strain P43/6/78 (ATCC 51139), which is pathogenic and weekly beta-hemolytic, were characterized in order to confirm its taxonomic position, and its relationships to other known species of intestinal spirochetes. In BHIS broth, P43/6/78 cells had a doubling time of 1-2 hr, and grew to a maximum cell density of 2 x 10**9 cells/ml over a 37-42 C temperature range. They hydrolyzed hippurate, utilized D-glucose, D-fructose, sucrose, D-trehalose, D-galactose, D-mannose, maltose, N-acetyl-D-glucosamine, D-glucosamine, pyruvate, L-fucose, D-cellobiose, and D-ribose as growth substrates, and produced acetate, butyrate, ethanol, H2 and CO2 as metabolic products. They consumed substrate amounts of oxygen and had a similar G + C content (24.6 mole%) to Serpulina hyodysenteriae B78**T (25.9 mole%, T = type strain). Phenotypic traits that could be used to distinguish P43/6/78 from S. hyodysenteriae and Serpulina innocens included their ultrastructural appearance (a total of 8 or 10 periplasmic flagella per cell, with 4-5 inserted at each end of the cell, thinner diameter, shorter length, and more pointed ends), their faster growth rate in liquid media, their hydrolysis of hippurate, and their metabolism of D-ribose. DNA-DNA relative reassociation using the S1 nuclease method showed that P43/6/78 was related to, but was genetically distinct from both S. hyodysenteriae B78**T (25-32% sequence homology) and S. innocens B256**T (24-25% sequence homology). These and previous results indicate that intestinal spirochete strain P43/6/78 represents a distinct species of Serpulina. We, therefore, propose that strain P43/6/78 be designated as the type strain of the new species Serpulina pilosicoli sp. nov.