Monday, 7 November 2005
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Survival Characteristics of Salmonella Enterica Serotype Newport in Manure, Manured Soils and Aqueous Solutions.

Youwen You, Shelley C. Rankin, Helen W. Aceto, Charles E. Benson, John Toth, and Zhengxia Dou. University of Pennsylvania, School of Veterinary Medicine, 382 W. Street Rd., Kennett Sq., PA 19348

Animal manure harbors a variety of pathogenic bacteria. Application of manure onto agricultural land can lead to pathogen spread and subsequent contamination of the environment. The objective of this study was to characterize the survival of Salmonella enetrica serotype Newport in manure, soil, and water systems. A multi-drug resistant (MDR) strain and a susceptible strain of Salmonella Newport (bovine origin), were inoculated into cow manure, which was then incubated alone or as manure-soil mixtures. A second trial tested the effect of soil particles and pH on the survival of the MDR strain in aqueous solutions at 48 oC. Results indicated that Salmonella Newport propagated rapidly in manure and soil systems at the beginning of the experiment. The initial multiplication was followed by different patterns of decrease. In manure alone, the organism showed a two-stage reduction: a slow and steady decrease followed by a sharp decline. In manured soils, population decrease appeared to be a slow and steady process. Both MDR and susceptible strains survived more than 160 days. The organisms survived the least in manure alone, the longest in manured-sterilized soil, The population decrease in manure or soils can be described by a first-order kinetic model. Results from the water study showed that neutral conditions favored survival of the organism while acid or alkaline conditions reduced persistence. Presence of Kaolinite or Montmorillonite in the aqueous solution enhanced survival. In conclusion, Salmonella Newport survived well in manure or manured soils; its survival in aqueous solution may be affected by pH as well as the presence of soil particles.

Handout (.pdf format, 417.0 kb)

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