No abstract

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.

Infant botulism is a rare disease in the UK, with the first case being recognized in 1978 and only five subsequent cases being reported before 2007. This study reports two unlinked cases of infant botulism, caused by two distinct strains of Clostridium botulinum (toxin types A and B, respectively), that occurred within a single month in the south-east of England in October 2007. The use of real-time PCR to detect C. botulinum neurotoxin genes in clinical specimens to improve the diagnostic procedure and to follow carriage of the causative organism in the infant gut is described. The laboratory investigation of these two cases demonstrated that a combination of the mouse bioassay, real-time PCR assays and conventional microbiological culture can provide rapid confirmation of a clinical diagnosis and affect patient management. Both infants (aged 4 and 8 months) were previously healthy prior to the onset of symptoms, and in both cases, a diagnosis of infant botulism was delayed for at least 10 days after initial admission to hospital. Once diagnosed, one of the infants was the first in the UK to be treated with human-derived botulism immunoglobulin. Real-time PCR was used to demonstrate that C. botulinum was excreted in the infants' faeces for up to 68 and 81 days, respectively. Despite the infrequency of infant botulism in the UK, clinicians should be aware of this rare but serious condition and should seek microbiological advice when presented with young infants with compatible symptomologies.

Wound infections due to Clostridium botulinum were not recognised in the UK and Republic of Ireland before 2000. C. botulinum produces a potent neurotoxin which can cause paralysis and death. In 2000 and 2001, ten cases were clinically recognised, with a further 23 in 2002, 15 in 2003 and 40 cases in 2004. All cases occurred in heroin injectors. Seventy cases occurred in England; the remainder occurred in Scotland (12 cases), Wales (2 cases) and the Republic of Ireland (4 cases). Overall, 40 (45%) of the 88 cases were laboratory confirmed by the detection of botulinum neurotoxin in serum, or by the isolation of C. botulinum from wounds. Of the 40 cases in 2004, 36 occurred in England, and of the 12 that were laboratory confirmed, 10 were due to type A. There was some geographical clustering of the cases during 2004, with most cases occurring in London and in the Yorkshire and Humberside region of northeast England.

Significance and Impact of the Study: The identification of species of Listeria from foods is important to monitor pathogenic strains and facilitates the implementation of control measures. This study shows the development and evaluation of a 5 0 exonuclease real-time PCR assay for the rapid identification of L. seeligeri, L. welshimeri, L. monocytogenes and L. ivanovii, L. grayi, L. innocua. The developed assay proved to be specific, rapid and reproducible and therefore could be implemented in busy specialist reference laboratories. AbstractThe Listeria genus comprises 10 recognized species. Listeria monocytogenes causes listeriosis in humans and other animals primarily via contaminated food or animal feed. Listeria ivanovii causes listeriosis in animals and on rare occasions in humans. The identification of nonpathogenic species of Listeria in foods indicates that conditions exist that support the growth of pathogenic strains and is used to facilitate the implementation of control and prevention measures. This study shows the development and evaluation of a 5 0 exonuclease real-time PCR assay for the rapid identification of Listeria seeligeri, Listeria welshimeri, L. monocytogenes, L. ivanovii, Listeria grayi and Listeria innocua. The assay consists of two triplexes that were evaluated using 53 cultures of Gram-positive bacteria, including 49 Listeria spp. from human, animal, food or food-processing environments. The assay was rapid, specific and reproducible and could identify each of the six species from a mixture of strains. The developed assay proved to be a powerful means of rapidly identifying Listeria species and could be usefully implemented in busy specialist reference laboratories.