Summary. The purpose of t h s study was to investigate the incidence of cases of sporadic diarrhoea associated with enterotoxigenic Clostridium perfringens. Cases were identified by detection of C. perfringens enterotoxin with the Oxoid RPLA kit, with confirmation by ELISA, in faecal specimens from isolated incidents of diarrhoea and from which no other enteropathogen had been isolated. In a 2-month study, 65 (18 %) of 370 specimens were enterotoxin positive. There was no predominant age group or sex in the enterotoxin-positive group, but a higher proportion (79 YO) was resident in the community than were enterotoxinnegative cases (34 %). Only four of the 65 enterotoxin-positive patients had received antibiotic therapy. Spore counts in most enterotoxin-positive patients were -c 105/g, indicating that detection of high numbers of C. perfringens is not useful in determining the aetiology of sporadic diarrhoea. Diagnosis should be confirmed by the detection of enterotoxin, but further work is required to assess whether an acceptable accuracy is obtained with the RPLA kit or whether ELISA is needed in all cases.

Aims: To determine the incidence of sporadic and apparently non-food related diarrhoea associated with Clostridium perfringens enterotoxin. Methods: Enzyme linked immunosorbent assay (ELISA) and reversed phase latex agglutination (RPLA) were used to detect C perfringens enterotoxin in faecal specimens from 818 sporadic cases of diarrhoea.Results: C perfringens enterotoxin was identified as a cause of sporadic diarrhoea in 56 of 818 (6.8%) cases. Diarrhoea was prolonged (three days or more) in most cases. Ages ranged from 3 months to 89 years, although most patients were over 60 years of age. Conclusions: These results suggest that C perfringens may be a cause of sporadic cases of diarrhoea when causes such as food consumption or cross-infection are absent, particularly in the elderly. Greiner) were coated overnight at 4°C with rabbit IgG against enterotoxin in 0O1 M sodium carbonate buffer, pH 9-8. Unbound sites were blocked by 1% bovine serum albumin (BSA) (Sigma) in 0-1 M sodium carbonate buffer, pH 9-8, incubated overnight at 4°C. Test extracts were incubated undiluted with 0 05% Tween 20 (Sigma) and after dilution 1 in 10 in PBS, 0 05% Tween 20 for 75 minutes at room temperature. Each extract was also incubated with neutralising antibody. After washing, rabbit anti-enterotoxin conjugated to horseradish peroxidase in PBS, 0-05% Tween 20, 1% BSA was incubated for two hours at room temperature. The enzyme substrate solution contained 0-5 mg/ml orthophenyldiamine in citrate phosphate buffer (2-43 ml 0-1 M citric acid, 2-57 ml 0-2 M sodium phosphate, and 5-0 ml distilled water). The reaction was stopped by adding 100 ,ul 4 M H2so4 and the absorbance at 492 nm was read in a Titertek Multiskan MCC plate reader. Wells containing no absorbed antibody or no test extract were included in each plate and gave an absorbance of less than 0I10.A standard curve on each plate was used to calculate the enterotoxin concentration. This covered the full range of absorbance with enterotoxin concentrations between 0 1 ng/ml and 100 ng/ml. The coefficient of variance (100 x standard deviation/mean) for intra-assay measurement of enterotoxin concentration was 2-5%. The coefficient of variation of interassay measurements of enterotoxin concentration was between 4-4% and 11-2%.C perfringens spore counts were determined following alcohol shock.' Pure cultures of C perfringens isolated from enterotoxin positive faeces were sent to the PHLS Food Hygiene Laboratory for serological typing using a set of 609 on 7 May 2018 by guest. Protected by copyright.

Serotyping (heat stable antigens) was performed on 398 strains of Campylobacter jejuni from faeces of human enteritis cases in England. Strains isolated over 12 months at three locations were heterogeneous with 33 HS serotypes represented. HS1 and HS4 complex were the predominant types (34% of all strains). The monthly strain frequency distributions were similar at the three locations. The late spring peak appeared to be associated with a rise in miscellaneous serotypes rather than with the emergence of any characteristic predominant serotype. PFGE DNA restriction profiling provided evidence of a high degree of genomic diversity within the common HS1 and HS4 complex serotypes, irrespective of the geographical source, yet some subtypes were common to more than one location. The study showed that C. jejuni strain subtypes from human enteric infections in England were highly diverse, and that HS serotyping must be combined with a more discriminatory subtyping method such as PFGE DNA profiling to provide an accurate basis for epidemiological surveillance.

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