Investigations into the possible causes of colitis and typhlocolitis were carried out on 85 pig units in the United Kingdom between 1992 and 1996. Serpulina pilosicoli was identified most commonly, occurring as the suggested primary agent on 21 (25 per cent) of the units but forming part of mixed infections on another 23 (27 per cent) of the units, the main co-infections being Yersinia pseudotuberculosis (eight units), proliferative enteropathy (six units), Salmonella species (four units) or Serpulina hyodysenteriae (two units). 'Atypical' Serpulina species, S hyodysenteriae, Salmonella typhimurium, Y pseudotuberculosis and Lawsonia intracellularis (proliferative enteropathy) were the suggested primary agents on seven, six, four, four and three units, respectively. Various combinations of mixed infections involving the latter organisms and other possibly incidental agents were recorded on another 10 units. Investigations on a further six units failed to detect any recognised pathogens. On units where S pilosicoli was the suggested primary agent, pigs ranging between 20 to 40 kg (eight to 16 weeks of age), but occasionally up to 50 kg, had diarrhoea and grew poorly over a period of two to three weeks. The prevalence was estimated to be between 5 and 15 per cent in affected batches, with a mortality of approximately 1 per cent. The clinical signs usually developed seven to 14 days after the moving and mixing of pigs. At postmortem examination, affected pigs had liquid contents in their colon, which contained accumulations of mucus in some chronic cases. Gross and histological lesions of colitis were prominent in the mid-spiral region of the colon. In mixed infections with Y pseudotuberculosis, Salmonella typhimurium or S hyodysenteriae, lesions were more extensive and affected the caecum as well as the colon. In the colon, lesions of proliferative enteropathy were usually confined to the proximal half of the ascending spiral but mixed infection with S pilosicoli caused more extensive colitis. Mixed infections were reported to prolong the time taken for pigs to recover naturally and to have a more detrimental effect on growth rates than S pilosicoli infection alone. Despite the successful treatment of batches of pigs with tiamulin or lincomycin, S pilosicoli infection persisted as a chronic problem on many units, with diarrhoea and colitis in successive batches of pigs unless prophylactic medication was used.

Serpulina pilosicoli is an anaerobic spirochete which has been isolated from the colons of pigs with enteric disease. The clinical and pathologic features of experimental infections of conventional pigs (born by normal farrowing with a naturally acquired intestinal flora) with three strains of S. pilosicoli were determined in order to confirm the enteropathogenicity of this species. Strains were derived from the colons of British pigs with colitis and passaged 8 to 10 times during expansion and purification in vitro. Eighteen ten-week-old Large White-Landrace cross pigs were each inoculated once orally with 0.7 ؋ 10 9 to 1.6 ؋ 10 9 of one of three strains of S. pilosicoli. Six pigs were challenged with each strain. Control pigs were dosed with uninfected broth medium or with 1.8 ؋ 10 7 cells of the nonpathogenic Serpulina innocens. Eight pigs (two to four per S. pilosicoli challenge group) developed soft or diarrheic feces (fecal dry matter < 24%) between 3 and 8 days after challenge, which persisted for 7 to 8 days or until necropsy at 14 days after challenge. Average weight gains in two of the three groups challenged with S. pilosicoli were significantly less than controls. The feed conversion ratios of all the groups challenged with S. pilosicoli were impaired compared to controls. The mean values for daily liveweight gain (and feed conversion ratio) for the three groups challenged with S. pilosicoli were 0.799 (2.13), 0.783 (2.05), and 0.844 kg (2.10), respectively, while that of the uninoculated controls was 0.944 kg (1.70). Gross lesions with slight mucosal thickening, congestion, and multifocal erosions were evident in seven of eight diarrheic pigs. The relative weights of the large intestines of pigs challenged with S. pilosicoli were significantly less than controls. Histologic lesions with an increase in mucosal height, infiltration of the lamina propria with mononuclear cells, mucosal erosion with mixed inflammatory cell infiltration, and goblet cell hyperplasia in colonic glands were evident in 15 of the 18 challenged pigs. S. pilosicoli was recovered on bacterial culture of the colon from all except one of the pigs with these histologic lesions. Serpulina sp. was clearly visible within the colonic glands of these affected pigs in silver-stained sections of the gut. Clinical and pathologic findings in control pigs were unremarkable, with no diarrhea or colonic lesions evident. The results provide further evidence that S. pilosicoli is a specific enteric pathogen for conventional pigs. It is capable of colonizing the large intestine and causing mucosal damage, which although mild is sufficient to result in significant adverse effects on growth.

phiHP33 phage orthologous sequences might be of significance in understanding virulence of different H. pylori strains.

Chlamydia-infecting bacteriophages, members of the Microviridae family, specifically the Gokushovirinae subfamily, are small (4.5-5 kb) single-stranded circles with 8-10 open-reading frames similar to E. coli phage fX174. Using sequence information found in GenBank, we examined related genes in Chlamydophila pneumoniae and Chlamydiainfecting bacteriophages. The 5 completely sequenced C. pneumoniae strains contain a gene orthologous to a phage gene annotated as the putative replication initiation protein (PRIP, also called VP4), which is not found in any other members of the Chlamydiaceae family sequenced to date. The C. pneumoniae strain infecting koalas, LPCoLN, in addition contains another region orthologous to phage sequences derived from the minor capsid protein gene, VP3. Phylogenetically, the phage PRIP sequences are more diverse than the bacterial PRIP sequences; nevertheless, the bacterial sequences and the phage sequences each cluster together in their own clade. Finally, we found evidence for another Microviridae phage-related gene, the major capsid protein gene, VP1 in a number of other bacterial species and 2 eukaryotes, the woodland strawberry and a nematode. Thus, we find considerable evidence for DNA sequences related to genes found in bacteriophages of the Microviridae family not only in a variety of prokaryotic but also eukaryotic species.

AMONG the intestinal spirochaete species of pigs, Brachyspira hyodysenteriae and Brachyspira pilosicoli are important agents of disease. B pilosicoli infection is variously termed spirochaetal diarrhoea (Taylor 1992), porcine colonic spirochaetosis (Muniappa and others 1997) or porcine intestinal spirochaetosis (Duhamel 1995). A recent study on pig herds with infectious colitis in the UK showed that Bpilosicoli was found in 25-0 per cent as a single pathogen, and in another 27-0 per cent as a copathogen (Thomson and others 1998). Transmission of Bpilosicoli occurs either through contamination of the immediate environment, or by direct contact between pigs. B pilosicoli can remain viable in contaminated water for 66 days (Oxberry and others 1998), thus increasing the potential for transmission. As there is no information on the activity of disinfectants against B pilosicoli, this short communication describes a study of the efficacy of seven disinfectant sanitisers against six field isolates and the type strain, ATCC-51139, of B pilosicoli, in the absence and presence of organic matter.The field isolates were from cases of porcine colitis, obtained as part of a surveillance programme for porcine colitis conducted by the Scottish Agricultural College (SAC). B pilosicoli grown anaerobically in brain heart infusion broth (Oxoid) supplemented with 5 per cent (w/v) filter-sterilised rabbit serum at 380C for two days was used as a bacterial suspension for assessing the disinfectant sanitisers.The tested products were of four different chemical groups, all manufactured by Antec International, and included three quaternary ammonium compounds, Ambicide (a disinfectant), DSC-1000 (a sanitiser) and HD-3 (a sanitiser); one amphoteric surfactant-caustic soda compound, Heavy Duty (a sanitiser); two tar organic acid compounds, Farm Fluid (a disinfectant) and Long Life (a disinfectant); and one peroxygen compound, Virkon S (a disinfectant).The efficacy tests were carried out according to the recommendations of the National Committee for Clinical Laboratory Standards for (NCCLS) antimicrobial susceptibility on anaerobic bacteria (NCCLS 1989), and adapted for testing the disinfectants. Ten-fold dilutions ( 1:10 up to 1 :100,000) of the disinfectant sanitisers were prepared in sterile deionised water (SDW) (for testing in the absence of organic matter) or in a suspension of sterile pig faeces (SPF) (for testing in the presence of organic matter) diluted 1:20 in phosphatebuffered saline solution. An aliquot of 0-1 ml ofbacterial suspension (approximately 105 colony-forming units/ml) was added to 0-9 ml of each serial dilution and the mixture was left for contact times of 30 or 60 minutes at room temperature (220C). Each suspension was then inoculated in triplicate on to blood agar plates, allowed to dry, and incubated anaerobically at 380C for three to four days. Control inocula, with no disinfectant, of each isolate were included.