Long-term survival ofEscherichia coliO157:H7 andSalmonellaTyphimurium in cowpats on pasture

Abstract

Aim: To investigate the survival of Escherichia coli O157:H7 and Salmonella Typhimurium in cowpats on pasture in a temperate Nordic climate. Methods and Results: The study consists of two parts, the first part using artificially created cowpats inoculated with E. coli O157:H7 and S. Typhimurium and the second part using cowpats from empty pastures on which cattle herds positive for E. coli O157:H7 had grazed 6 month previously. Artificial cowpats were created, placed in an outdoor field station in June, August and October, and sampled over 1 year. Escherichia coli O157:H7 and S. Typhimurium were analysed by standard culture methods. The results showed viable E. coli O157:H7 and S. Typhimurium in the sampled cowpats throughout the 365-day sample period for the June trial, 250 days for the August trial and 40-70 days for the October trial. In addition, 200 natural cowpats were sampled from eight pastures that had previously held E. coli O157:H7 positive cattle herds. Five positive E. coli O157:H7 isolates were obtained, all with the same multi-locus variable number tandem repeat analysis pattern as had been found on the pasture the previous grazing season. Conclusions: Escherichia coli O157:H7 and S. Typhimurium can survive in cowpats up to a year and persist throughout a winter season. Therefore, there is a possibility that cowpats can act as a reservoir and be a source of reinfection of Salmonella or E. coli O157:H7 in cattle between grazing seasons. Significance and Impact of the Study: The obtained results can provide valuable information for managing the risk posed by zoonotic pathogens originating from farm environments. nd nd nd nd Journal of Applied Microbiology 126, 651--660

Semi-Quantitative Biosecurity Assessment Framework Targeting Prevention of the Introduction and Establishment of Salmonella Dublin in Dairy Cattle Herds

“…However, it is reasonable to believe that a higher dry matter content will extend the survival period because of less exposure to UV radiation. This is supported by the ability of S. Typhimurium to be viable in cow pats for up to a year, depending on the decomposition influence by season and weather conditions [ 77 ]. Most slurries in Denmark applied to grassing areas or areas used for forage have a dry matter content of >5% and are often injected into the soil.…”

High concentration of sodium chloride could induce the viable and culturable states of Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis

“…infections have been associated with animal meat and raw milk, but these diseases can also be transmitted through contaminated water (Gruzdev et al, 2012). In addition, the two pathogens can survive for weeks or years in water and soil if environmental conditions, such as temperature, humidity and pH, are favourable (Nyberg et al, 2018). Recently, Ioanna et al (2018) have shown that populations of E. coli O157:H7 remained constant up to 28 days (>6Á20 log 10 CFU per g) and then slightly decreased until the 90 days of storage.…”