Escherichia coliO157:H7 andSalmonellain Water and Soil from Tall Fescue Paddocks

Abstract

Six 1-ha paddocks of tall fescue (Festuca arundinacea) grazed by Gelbvieh x Angus heifers from 1 March to 21 June 2005 were used to determine the prevalence of Escherichia coli O157:H7 and Salmonella in water tanks, and standing water and surface soil surrounding water tanks in tall fescue paddocks grazed by cattle. Paddocks included two each of Kentucky-31 endophyte-infected tall fescue (E+), Jesup tall fescue with the AR542 endophyte strain (MaxQ), and HiMag tall fescue with strain 4 endophyte (HiMag4). Samples were collected weekly (6 June to 5 July) from water tanks (n = 30), and standing water (n = 18) and surface soil (n = 30) surrounding the water tanks in each paddock commencing 3 weeks prior to termination of grazing until 2 weeks after cattle removal. Prevalence of E. coli O157:H7 tended (p = 0.07) to be increased in standing water and surface soil surrounding water tanks when cattle were present. Presence of cattle resulted in muddy conditions surrounding water tanks. Consumption of E+ tall fescue did not influence (p > 0.10) the prevalence of E. coli O157:H7 or Salmonella in or around water tanks. Neither E. coli O157:H7 or Salmonella were detected in water tanks. Total percentage of standing water samples positive for E. coli O157:H7 was 27.8% and 5.6% for Salmonella. Escherichia coli O157:H7 (6.7%) and Salmonella (10%) also were detected in the surface soil surrounding the water tanks. We conclude that areas surrounding water tanks in tall fescue paddocks can be reservoirs of pathogenic bacteria.