Submitted to: Federation of European Microbiological Societies Microbiology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/1996
Publication Date: N/A
Citation: Interpretive Summary: We recently described and named a newly recognized spirochete, Serpulina pilosicoli, which is an emerging intestinal pathogen of swine. This bacterial pathogen causes a disease in pigs called intestinal spirochetosis (also called spirochetal diarrhea) which is characterized by diarrhea, slower growth, and dehydration in affected animals. The incidence and economic impact of the disease is not known. However, reports from diagnostic labs indicate that S. pilosicoli is found more often than Serpulina hyodysenteriae, a related spirochete which causes the disease swine dysentery (estimated economic cost, $100 million per year). We have characterized S. pilosicoli strains isolated from pigs, as well as from humans with diarrhea. Differences between S. pilosicoli and other intestinal spirochetes, such as how fast they grow, what sugars they consume, what they look like, and if they are identified by a S. pilosicoli-specific laboratory test, are described. These differences can be used in the development of diagnostic tests for S. pilosicoli based on selective culture methods, as well as nucleic acid-based tests using PCR. These tests will enable diagnostic laboratories to identify S. pilosicoli, differentiate it from the closely related S. hyodysenteriae, and identify its prevalence and economic impact in swine. The same tests will provide information on the role of these bacteria in diarrheal diseases of humans, and on the potential for the transmission of these bacterial pathogens from animals to humans.
Technical Abstract: The phenotypic characteristics of three Serpulina pilosicoli strains isolated from humans with diarrhea (WesB, Kar, Hrm7) and two porcine S. pilosicoli strains isolated from pigs with intestinal spirochetosis (1648, 3295) were compared with the type strain of the species P43/6/78**T (T=type strain) and other intestinal spirochetes within the genus Serpulina. All S. pilosicoli strains had a characteristic ultrastructural appearance, displayed similar growth rates, hydrolyzed hippurate, lacked beta-glucosidase activity, utilized D-ribose as a growth substrate, had similar sensitivities to rifampicin and spiramycin, and had a similar whole cell protein Western blot profile. The only consistent phenotypic characteristic that differentiated human strains from porcine strains of S. pilosicoli was that the human strains all utilized the pentose sugar D-xylose. The protein profiles were distinct from those of the type strains of Serpulina hyodysenteriae (B78**T) and Serpulina innocens (B256**T). These distinguishing phenotypic traits appear useful for identifying S. pilosicoli.