[An outbreak of diarrheal disease caused by enterotoxigenic Clostridium perfringens following exposure to a contaminated environment in a nursing home].

We herein report an outbreak of non-food-borne diarrhea which occurred in a nursing home due to enterotoxigenic Clostridium perfringens. The regional public health center in Gifu, Japan, recognized 7 patients with diarrhea in a nursing home, suspecting a food-borne illness. Bacteriological and epidemiological studies indicated that enterotoxigenic C. perfringens was the causative agent. However, suspected foods, the kitchen and the cooks carried no enteropathogenic bacteria, indicating that this outbreak was a non-food-borne diarrhea. The swab specimens obtained from the residential area of the nursing home were found to have enterotoxigenic C. perfringens. Isolates from the stool specimens of patients and environment were all serotype TW47, showing susceptibilities to ampicillin, levofloxacin, and clindamycin very similar to each other, and had banding patterns identical to each other by pulsed-field gel electrophoresis. These results strongly supported the existence of monoclonal spread of an enterotoxigenic C. perfringens among the environment of the nursing home and the residents. During 3 weeks 14 residents were involved in this outbreak. The extensive effort of keeping the residential area clean led to a prompt cease of this outbreak.

New rapid enzyme-linked immunosorbent assay to detect antibodies against bacterial surface antigens using filtration plates.

An easy and rapid ELISA system, Filtration ELISA, to detect antibodies against bacterial cell surface antigens was developed using a 96-well filtration plate fitted with a 0.22microm membrane (MultiScreen-GV, Millipore). Bacterial whole cells were used as antigens without fixing the cells with formalin etc. The whole cell antigens were washed by vacuum filtration through a filter and resuspended in washing buffer. Assay reactions could be done in the wells without losing the solution. The technique was established using antisera of mice immunized with Escherichia coli, and then evaluated by assaying antibodies to Shiga-toxin producing E. coli O157:H7 (STEC), Staphylococcus aureus and Lactobacillus acidophilus in fecal extracts of 157 children who had eaten school lunches contaminated with STEC in comparison with 25 age-matched control children. The lunch group showed significantly higher IgA antibody titers against STEC than the control group (p<0.0005), but not against L. acidphilus. The results indicate that Filtration ELISA is a quantitative and specific technique for measuring antibodies against antigens on the surface of bacteria without extracting antigens from the bacteria. This technique is widely applicable to the assay of antibodies in various samples including serum and fecal extract against various kinds of bacteria.