BMC Microbiology (Dec 2009)

Temporal and spatial patterns of bovine <it>Escherichia coli </it>O157 prevalence and comparison of temporal changes in the patterns of phage types associated with bovine shedding and human <it>E. coli </it>O157 cases in Scotland between 1998-2000 and 2002-2004

  • Low J Christopher,
  • Reilly William,
  • Synge Barti A,
  • Smith Alastair W,
  • Knight Hazel I,
  • Matthews Louise,
  • Ternent Helen E,
  • Locking Mary E,
  • Allison Lesley,
  • Mellor Dominic J,
  • McKendrick Iain J,
  • Chase-Topping Margo E,
  • Pearce Michael C,
  • Reid Stuart WJ,
  • Gunn George J,
  • Woolhouse Mark EJ

DOI
https://doi.org/10.1186/1471-2180-9-276
Journal volume & issue
Vol. 9, no. 1
p. 276

Abstract

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Abstract Background Escherichia 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. Results Animal 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 P 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 (P = 0.002). Conclusion There 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.