Recognition of Two New Species of Intestinal Spirochetes: Serpulina intermedia sp. nov. and Serpulina murdochii sp. nov.

Abstract

On the basis of DNA-DNA hybridization data, nine intestinal spirochete strains were grouped into five genospecies. Three of these genospecies were previously recognized Serpulina species, Serpulina hyodysenteriae (type strain, B78), Serpulina innocens (type strain, B256), and Serpulina pilosicoli (type strain, P43/6/78; previously "Anguillina coli"). The other two genospecies were found to be new Serpulina species, for which we propose the names Serpulina intermedia sp. nov. (with type strain PWS/A) and Serpulina murdochii sp. nov. (with type strain 56-150). S. intermedia and S. murdochii cells had a typical spirochete ultrastructure with 22 to 28 periplasmic flagella per cell. Various soluble sugars were growth substrates for S. intermedia and S. murdochii. During growth in basal heart infusion broth supplemented with fetal calf serum beneath an 0,-N, (1:99) atmosphere, cells of these new species consumed oxygen and glucose and produced H,, CO,, acetate, butyrate, and ethanol. The G+C content of the DNA of S. murdochii 56-150T was 27 mol%, and the G+C content of the DNA of S. intermedia PWS/AT was 25 mol%. In addition, a restriction fragment length polymorphism-PCR assay for the detection of intestinal spirochetes was developed. The assay was based on generation and restriction endonuclease analysis (with HinfI, TaqI, Sau3A, and 4421011) of a 558-bp amplicon of ribosomal DNA (rDNA) encoding 16s rRNA. The PCR amplification was specific for Serpulina species and Brachyspira aalborgi. Four restriction digest patterns were found for the five Serpulina species. HinfI restriction differentiated S. murdochii and S. innocens from the other species. Sau3A and TaqI restrictions gave unique fragment patterns for S. murdochii and S. pilosicoli, respectively. S. hyodysenteriae and S. intermedia DNAs gave the same fragment pattern regardless of the enzyme tested. B. aalborgi was differentiated from the Serpulina species by MboII digestion of the 16s rDNA amplicon. Swine (367 40) dysentery (13) and porcine intestinal spirochetosis can be differentiated by their clinical signs. Swine dysentery is a severe, mucohemokhagic diarrheal disease that sometimes leads to death. Porcine intestinal spirochetosis is a mucus-containing, nonbloody diarrheal disease which leads to a poor growth rate in young pigs. The etiological agents of these two diseases are separate species of intestinal spirochetes belonging to the genus Serpulina, the strongly hemolytic organism Selpulina hyodysenteriae (13) and the weakly hemolytic organism Serpulina pilosicoli (formerly called "Anguillina coli") (40), respectively. Some human intestinal spirochetes (1, 18, 29) have been identified as S. pilosicoli (25, 41). Other previously characterized spirochetes found in the gastrointestinal tracts and feces of animals and humans include two nonpathogenic species from swine, Selpulirza innocens (31) and Treponema succinifaciens (5), and a human spirochete, Brachyspira aalborgi, which is believed to be a commensal (14). There undoubtedly are other intestinal spir...

The prevalence of Serpulina pilosicoli in humans and domestic animals in the Eastern Highlands of Papua New Guinea

“…Using multilocus enzyme electrophoresis, the non-S. pilosicoli strains isolated from dogs (3) and pigs (3) were closely related to members of the non-pathogenic porcine species S. innocens (D. J. Trott and D. J. Hampson, unpublished data), suggesting that they have no clinical significance [2]. The single strain from a chicken corresponded to the recently proposed species, Serpulina intermedia [38]. The finding of S. pilosicoli strains in dogs and a duck suggests that cycling of infection between animals and humans may occur in the villages.…”

Brachyspira murdochii Colitis in Pigs

“…In addition to affecting pigs, B murdochii has been isolated from hens 13 and rats (wild and laboratory) 14 without history of intestinal disease. Hitherto, B murdochii has not been considered to be pathogenic, 2,4,11 but the recent detection of B murdochii by polymerase chain reaction (PCR) in cases of porcine colitis negative for B hyodysenteriae and B pilosicoli warrants speculation on the potential pathogenecity of the bacterium. 15 The aim of this study was to report a case of naturally acquired colitis and experimental colonic infection caused by B murdochii in pigs.…”

Intestinal Spirochetosis in a 21-Month-Old Thoroughbred Colt.

“…The cells of B. pilosicoli generally are shorter and thinner than those of the other Brachyspira species and have fewer axial filaments (4 to 6 axial filaments inserted at each end) [8,11]. It is difficult to distinguish cells of B. hyodysenteriae, B. intermedia and B. murdochii based on cell dimensions, cell morphology and numbers of axial filaments under culture conditions [8]. In the present study, the Type 1 and 2 spirochetes could belong to Brachyspira species other than B. pilosicoli, and Type 3 to B. pilosicoli or a closely related species.…”

“…Thus, various spirochetes are present in the large intestine in horses, and some invasive ones might be capable of inducing colitis and diarrhea in immature or immunocompromised horses. The cells of B. pilosicoli generally are shorter and thinner than those of the other Brachyspira species and have fewer axial filaments (4 to 6 axial filaments inserted at each end) [8,11]. It is difficult to distinguish cells of B. hyodysenteriae, B. intermedia and B. murdochii based on cell dimensions, cell morphology and numbers of axial filaments under culture conditions [8].…”