title: Short communication: turbidity as an indicator of Escherichia coli presence in water troughs on cattle farms.
abstract: Studies have shown that water-drinking troughs are an important source of Escherichia coli infection on cattle farms, and a study was designed to provide farmers with an easy-to-use tool to monitor trough contamination and help determine when to empty and clean water troughs. A total of 164 water troughs were sampled on 33 cattle farms, and the on-farm turbidity tester results were found to be significantly correlated with laboratory turbidity results. Turbidity was associated with E. coli concentration, although the association was not linear. Emptying the troughs within a week of sampling was shown to reduce the turbidity score, but no linear association between time of emptying and E. coli concentration was discovered. A turbidity score of 4 was set as a cutoff point for when to clean a trough, yielding a sensitivity of 0.94 and a specificity of 0.03 for identifying a level of E. coli concentration that was more likely to contain E. coli O157 (>5,800 cfu/100 mL).
authors.affiliation: Veterinary Laboratories Agency, and Centre of Epidemiology and Risk Analysis, Woodham Lane, New Haw Addlestone, Surrey KT15 3PB, United Kingdom. r.smith@vla.defra.gsi.gov.uk
authors.forename: R P
authors.initials: RP
authors.lastname: Smith
authors.forename: G A
authors.initials: GA
authors.lastname: Paiba
authors.forename: J
authors.initials: J
authors.lastname: Ellis-Iversen
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology / Q000517:prevention & control; D004197:Disease Reservoirs / Q000382:microbiology; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000517:prevention & control / Q000662:veterinary; D019453:Escherichia coli O157 / Q000302:isolation & purification; D009391:Nephelometry and Turbidimetry; D012680:Sensitivity and Specificity; D014867:Water; D014871:Water Microbiology
chemical_list: D014867:Water