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Infant botulism was confirmed in a 5-month-old female by both isolation of Clostridium botulinum type B and by detection of type B botulinum neurotoxin in rectal washout and faeces. DNA fingerprinting of nine isolates from faeces yielded two different amplified-fragment length polymorphism (AFLP) patterns. C. botulinum was isolated from two of 14 food and drink items from the patient's home: C. botulinum type A was recovered from an opened container of dried rice pudding and C. botulinum type B from opened infant formula milk powder. Ten C. botulinum type B isolates from the opened infant formula yielded four AFLP patterns, two of which were indistinguishable from the clinical isolates. Fifteen unopened foods were tested and C. botulinum type B of a unique AFLP pattern was recovered from one unopened infant formula of the same batch as the opened container. It is suggested that multiple C. botulinum were present in both food and the intestine during infant botulism.

There are three main, naturally occurring, epidemiological types of botulism: food-borne, intestinal colonization (infant botulism) and wound botulism. The neurological signs and symptoms are the same for all three epidemiological types and may include respiratory paralysis. Wound botulism is caused by growth of cells and release of toxin in vivo, is associated with traumatic wounds and abscesses and has been reported in drug users, such as those injecting heroin or sniffing cocaine. Up to the end of 1999 there were no confirmed cases of wound botulism in the UK. Between the beginning of 2000 and the end of December 2002, there were 33 clinically diagnosed cases of wound botulism in the UK and Ireland. All cases had injected heroin into muscle or by 'skin popping'. The clinical diagnosis was confirmed by laboratory tests in 20 of these cases. Eighteen cases were caused by type A toxin and two by type B toxin.

Faecal specimens from 843 cases of diarrhoea in the community were tested for the presence of Clostridium difficile cytotoxin and Clostridium perfringens enterotoxin. C. difficile cytotoxin was detected in faecal specimens from 0.6 % of cases aged at least 2 years by using a Vero cell assay. Factors associated with detection of C. difficile cytotoxin were antibiotic therapy, age over 60 years and living in a home with other elderly people. Three methods were used for the detection of C. perfringens enterotoxin: a Vero cell assay, a commercial (TechLab) enzyme immunoassay (EIA) and an in-house EIA. The lower level of detection of pure C. perfringens enterotoxin in buffer was 0.01 micro g ml(-1) by the TechLab EIA and 1.0 micro g ml(-1) by the Vero cell assay. C. perfringens enterotoxin was detected by using the TechLab EIA in faecal specimens from 2.5 % of cases. This commercial EIA was less sensitive than the in-house EIA, detecting only 31 % of positive cases, but was specific and could be used for outbreak investigation by routine diagnostic laboratories. Age over 60 years was a factor associated with C. perfringens enterotoxin detection; this age group may be targeted for testing.

Pathogenic species of the genus Clostridium may contaminate the materials used in the injection of drugs and under the right conditions may cause serious or life-threatening disease. C. novyi type A was implicated in an outbreak of severe infection with high mortality in injecting drug users who injected heroin extravascularly. The isolation of such highly oxygen-sensitive clostridia from clinical material may require adherence to enhanced methods and, once isolated, commercially available anaerobe identification kits alone may not give an accurate identification. Additional phenotypic tests that are useful in recognising the main pathogenic species are described. Differentiation of C. novyi type A from C. botulinum type C in reference laboratories was based on 16S rDNA sequence data and specific neutralisation of cytopathic effects in tissue culture.

As part of the follow-up investigations associated with an outbreak of severe illness and death among illegal injecting drug users during 2000, 43 cultures of Clostridium novyi type A, 40 C. perfringens type A and 6 isolates of Bacillus cereus were characterised by amplified fragment length polymorphism (AFLP) analysis. Among the 43 C. novyi isolates, 23 different AFLP profiles were detected. The same AFLP profile was detected in isolates from 18 drug users investigated during 2000 from Scotland, England, the Republic of Ireland and Norway and a wound from a patient in 2000 who was not identified as a drug user. Unique AFLP profiles were obtained from four drug users from England and the Republic of Ireland, 10 historical isolates from culture collections, an isolate from food (1989) and three isolates from wounds (1995, 1991, 1988). The 40 C. perfringens isolates were from 13 drug users, the contents of one syringe and two samples of heroin. Sixteen AFLP types of C. perfringens were distinguished and there was little evidence for commonality among the isolates. The AFLP types of C. perfringens from heroin differed and were unique. Six isolates of B. cereus were from four drug users and two samples of heroin. Four different AFLP patterns were distinguished. Three AFLP types were isolated from four drug users. B. cereus isolates from an aspirate and a heroin sample collected from the same drug user were identical, and were also indistinguishable from an isolate from a groin infection in a second drug user. The AFLP type of the isolate from a second and unrelated heroin sample was unique. The AFLP results showed no or very limited evidence for commonality between the different isolates of B. cereus and C. perfringens. In marked contrast, the C. novyi isolates from the majority of the drug users during 2000 were homogeneous, suggesting a common source or clonal selection of a C. novyi type, or both, which either had an adaptive advantage in spore germination, survival or growth following the drug preparation and the injection procedure, or produced a more severe clinical presentation.

The purpose of this 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 higher proportion (79%) was resident in the community than were enterotoxin-negative cases (34%). Only four of the 65 enterotoxin-positive patients had received antibiotic therapy. Spore counts in most enterotoxin-positive patients were < 10(5)/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.

Clostridium perfringens type A is a common cause of food-poisoning. Production of lecithinase (alpha toxin) is frequently used to identify the organism. Details of 10 outbreaks of food-poisoning caused by lecithinase-negative C. perfringens are reported here.