Immunomagnetic separation of the intestinal spirochaetes Brachyspira pilosicoli and Brachyspira hyodysenteriae from porcine faeces

The Spirochete Brachyspira pilosicoli, Enteric Pathogen of Animals and Humans

Brachyspira pilosicoli is a slow-growing anaerobic spirochete that colonizes the large intestine. Colonization occurs commonly in pigs and adult chickens, causing colitis/typhlitis, diarrhea, poor growth rates, and reduced production. Colonization of humans also is common in some populations (individuals living in village and peri-urban settings in developing countries, recent immigrants from developing countries, homosexual males, and HIV-positive patients), but the spirochete rarely is investigated as a potential human enteric pathogen. In part this is due to its slow growth and specialized growth requirements, meaning that it is not detectable in human fecal samples using routine diagnostic methods. Nevertheless, it has been identified histologically attached to the colon and rectum in patients with conditions such as chronic diarrhea, rectal bleeding, and/or nonspecific abdominal discomfort, and one survey of Australian Aboriginal children showed that colonization was significantly associated with failure to thrive. B. pilosicoli has been detected in the bloodstream of elderly patients or individuals with chronic conditions such as alcoholism and malignancies. This review describes the spirochete and associated diseases. It aims to encourage clinicians and clinical microbiologists to consider B. pilosicoli in their differential diagnoses and to develop and use appropriate diagnostic protocols to identify the spirochete in clinical specimens.

Effect of soy on faecal dry matter content and excretion of Brachyspira hyodysenteriae in pigs

The aim of this study was to investigate the effect of a soy diet on the excretion of Brachyspira hyodysenteriae in five farms with subclinically infected pigs. The effects on general health, faecal consistency and dry matter were analysed. In total, 200 pigs of different ages (group 1 <100 days of age (n=120) and group 2 ≥100 days (n=80)) were randomly assigned to the control (C) and the treatment (T) groups. Group C received the farm's standard diet. In group T half of the daily feed ration was replaced by pure soy on two consecutive days. Faecal scores were used to determine faecal consistency and a microwave method to assess faecal dry matter content (FDMC). In age group 1, soy feeding resulted in a statistically significant decrease of the FDMC of 2.5 per cent compared with group C and in age group 2 in a significant increase of 2.2 per cent compared with group C at day 2. Overall seven (T: 5, C: 2) out of 597 faecal samples tested positive for B hyodysenteriae by PCR.

In conclusion, a high soy diet applied over two days influenced the faecal consistency and the FDMC in growers, finishers and sows under field conditions. Further investigations with more sensitive diagnostic methods are needed to prove a potential influence of a high soy diet on the detection rate of B hyodysenteriae in subclinically infected herds.

Human intestinal spirochetosis--a review

Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS.

Immunomagnetic separation and coagglutination of Vibrio parahaemolyticus with anti-flagellar protein monoclonal antibody

Mice were immunized by injection of Vibrio parahaemolyticus ATCC 17802 polar flagellin in order to produce monoclonal antibodies (mAbs). mAbs were analyzed by anti-H enzyme-linked immunosorbent assay using V. parahaemolyticus polar flagellar cores. The mAb exhibiting the highest anti-H titer was coated onto Cowan I Staphylococcus aureus cells at a concentration of 75 microg/ml cell suspension and used for slide coagglutination. Of 41 isolates identified genetically as V. parahaemolyticus, 100% coagglutinated with the anti-H mAb within 30 s, and the mAb did not react with 30 isolates identified as Vibrio vulnificus. A strong coagglutination reaction with V. parahaemolyticus ATCC 17802 was still observed when the S. aureus cells were armed with as little as 15 microg of mAb/ml S. aureus cell suspension. At this concentration, the mAb cross-reacted with three other Vibrio species, suggesting that they share an identical H antigen or antigens. The anti-H mAb was then used to optimize an immunomagnetic separation protocol which exhibited from 35% to about 45% binding of 10(2) to 10(3) V. parahaemolyticus cells in phosphate-buffered saline. The mAb would be useful for the rapid and selective isolation, concentration, and detection of V. parahaemolyticus cells from environmental sources.