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The risk for diarrhea-associated HUS was higher for children infected with Escherichia coli O157 phage type (PT) 2 and PT21/28 than for those infected with other PTs.

To determine environmental risk factors for sporadic E. coli O157 infection in Scotland we undertook a prospective, matched case-control study between 1 October 1996 and 31 March 1999. One hundred and eighty-three cases and 545 matched controls were recruited. Contact with animal faeces (OR = 3.65; 95% CI 1.81, 7.34: P < 0.0005) and likely contact with animal faeces (OR = 4.8; 95% CI 2.42, 9.48; P < 0.0005) emerged as strong risk factors for infection. Certain exposures (mainly food-related) were inversely associated with infection i.e. were statistically protective. Most striking was the consumption of bottled water (OR = 0.28; 95% CI 0.15, 0.52; P < 0.0005). Transmission of E. coli O157 does not occur simply through contaminated food. Members of the public need to be aware of the potential for acquiring E. coli O157 through contamination of the environment with animal faeces so that they may take measures to mitigate their risk.

In the United Kingdom there has been a marked increase in the number of human infections caused by toxigenic Corynebacterium ulcerans. During 2002 and 2003 the organism was also isolated from several domestic cats with bilateral nasal discharge. As C. ulcerans has never previously been isolated from cats, the 16S rRNA gene from three cat isolates was sequenced to confirm their species identities. Fifty clinical isolates from the United Kingdom isolated from 1986 to 2003 and seven cat isolates were characterized by ribotyping to determine whether the ribotypes of the cat isolates were genotypically related to those found for human clinical isolates. For comparison, the genotypes of 11 overseas isolates and 13 isolates from H. R. Carne's collection isolated between 1933 and 1979 were also determined. Strains isolated from domestic cats were found to exhibit the predominant ribotypes observed among human clinical isolates, suggesting that C. ulcerans isolated from cats could be a potential reservoir for human infection.

BackgroundEscherichia coli O157 is an important cause of acute diarrhoea, haemorrhagic colitis and, especially in children, haemolytic uraemic syndrome (HUS). Incidence rates for human E. coli O157 infection in Scotland are higher than most other United Kingdom, European and North American countries. Cattle are considered the main reservoir for E. coli O157. Significant associations between livestock related exposures and human infection have been identified in a number of studies.ResultsAnimal Studies: There were no statistically significant differences (P = 0.831) in the mean farm-level prevalence between the two studies (SEERAD: 0.218 (95%CI: 0.141-0.32); IPRAVE: 0.205 (95%CI: 0.135-0.296)). However, the mean pat-level prevalence decreased from 0.089 (95%CI: 0.075-0.105) to 0.040 (95%CI: 0.028-0.053) between the SEERAD and IPRAVE studies respectively (P < 0.001). Highly significant (P < 0.001) reductions in mean pat-level prevalence were also observed in the spring, in the North East and Central Scotland, and in the shedding of phage type (PT) 21/28. Human Cases: Contrasting the same time periods, there was a decline in the overall comparative annual reported incidence of human cases as well as in all the major PT groups except 'Other' PTs. For both cattle and humans, the predominant phage type between 1998 and 2004 was PT21/28 comprising over 50% of the positive cattle isolates and reported human cases respectively. The proportion of PT32, however, was represented by few (<5%) of reported human cases despite comprising over 10% of cattle isolates. Across the two studies there were differences in the proportion of PTs 21/28, 32 and 'Other' PTs in both cattle isolates and reported human cases; however, only differences in the cattle isolates were statistically significant (P = 0.002).ConclusionThere was no significant decrease in the mean farm-level prevalence of E. coli O157 between 1998 and 2004 in Scotland, despite significant declines in mean pat-level prevalence. Although there were declines in the number of human cases between the two study periods, there is no statistically significant evidence that the overall rate (per 100,000 population) of human E. coli O157 infections in Scotland over the last 10 years has altered. Comparable patterns in the distribution of PTs 21/28 and 32 between cattle and humans support a hypothesized link between the bovine reservoir and human infections. This emphasizes the need to apply and improve methods to reduce bovine shedding of E. coli O157 in Scotland where rates appear higher in both cattle and human populations, than in other countries.