Herd-level risk factors associated with the presence of Phage type 21/28 E. coli O157 on Scottish cattle farms

Jo EB Halliday¹ , Margo E Chase-Topping² , Michael C Pearce³ , Iain J McKendrick⁴ , Lesley Allison⁵ , Dave Fenlon³ , Chris Low³ , Dominic J Mellor⁶ , George J Gunn³ and Mark EJ Woolhouse²

¹Centre for Infectious Diseases, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK

²Centre for Infectious Diseases, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh, EH9 3JF, UK

³Scottish Agricultural College, Animal Health Group, Research Division, King's Buildings, West Mains Road, Edinburgh, EH9 3JG, UK

⁴Biomathematics & Statistics Scotland, King's Buildings, West Mains Road, Edinburgh, EH9 3JZ, UK

⁵Scottish E. coli O157 Reference Laboratory, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK

⁶Comparative Epidemiology & Informatics, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK

author email corresponding author email

BMC Microbiology 2006, 6:99doi:10.1186/1471-2180-6-99


Published:	2 December 2006

Abstract

Background

E. coli O157 is a bacterial pathogen that is shed by cattle and can cause severe disease in humans. Phage type (PT) 21/28 is a subtype of E. coli O157 that is found across Scotland and is associated with particularly severe human morbidity.

Methods

A cross-sectional survey of Scottish cattle farms was conducted in the period Feb 2002-Feb 2004 to determine the prevalence of E. coli O157 in cattle herds. Data from 88 farms on which E. coli O157 was present were analysed using generalised linear mixed models to identify risk factors for the presence of PT 21/28 specifically.

Results

The analysis identified private water supply, and northerly farm location as risk factors for PT 21/28 presence. There was a significant association between the presence of PT 21/28 and an increased number of E. coli O157 positive pat samples from a farm, and PT 21/28 was significantly associated with larger E. coli O157 counts than non-PT 21/28 E. coli O157.

Conclusion

PT 21/28 has significant risk factors that distinguish it from other phage types of E. coli O157. This finding has implications for the control of E. coli O157 as a whole and suggests that control could be tailored to target the locally dominant PT.