Antibiotic Resistant and Pathogenic Bacteria Associated with Rain Runoff following Land Application of Poultry Litter

Poultry rearing in the United States is approximately a thirty million dollar per year industry. To produce this large number of product, a by-product such as poultry litter is inevitable. The land application of poultry litter as an organic fertilizer is an ideal choice for the disposal of this high nitrogen, high organic waste. However, some precautions must be observed, particularly with regard to potential rain-mediated runoff of litter-related microorganisms following any large-scale precipitation events, such as those common to the Mississippi area. To investigate this phenomenon, poultry litter application will be simulated in a controlled greenhouse environment. Litter will be applied to Bermuda grass (Cynodon dactylon) plots held within runoff trays designed to simulate environmental conditions, by simulating slope, soil type, and climate. A rainfall simulator will be used to simulate precipitation events. Rainfall will be simulated on a weekly basis for a total of 4 consecutive weeks. Following each rain event, runoff and leachate samples will be collected for microbial analysis. Soil will be collected prior to the commencement of the experiment and following experiment termination. Total Heterotrophic Plate Count bacteria, antibiotic resistant bacteria, fecal coliforms, enterococci, staphylococci, Clostridium perfringens, and Salmonella spp. will all be investigated using both cultural and molecular methods. Select pathogens, indicator, and heterotrophic plate count bacteria will be selected for further genus typing and antibiotic resistance. In ad ition to the litter applied runoff trays, control trays in which no litter will be applied and chemical fertilizer applications will be used as comparison controls. Results from this experiment will lead to future in field application studies, under environmental conditions. These experiments will then be used to identify optimal field conditions necessary to achieve decreased potential for microbial runoff and subsequently provide much needed information to the area of litter application.