Presentation Type

Poster

Title of Abstract

Effects of Agrochemicals on the Growth Rates of Bacterial Pathogens and Fecal Indicator Bacteria

Abstract

Agricultural intensification in recent years has raised concern about the risks agricultural practices pose to human health. Waste from livestock, potentially containing zoonotic pathogens, can be contributed to water bodies via storm water and agricultural runoff. Additionally, agricultural runoff is likely to contain agrochemicals, such as fertilizers and pesticides. Understanding the impact these agrochemicals have on the growth of zoonotic pathogens and fecal indicator bacteria (FIB) is vital to improving agricultural and water management practices to safeguard public health. This experiment focused on the impact of agrochemicals on the growth rates of FIBs (Escherichia coli and Enterococcus faecalis) and agriculturally-derived pathogens (E. coli O157:H7 and Salmonella enterica) under nutrient-limited conditions. By isolating the bacteria from extraneous variables, such as competition and predation, potential direct effects of agrochemicals on growth rates could be identified. Agrochemical treatments consisted of inorganic fertilizer as well as the pesticides atrazine (herbicide), malathion (insecticide), or chlorothalonil (fungicide) at 1x and 2x expected environmental concentration (EEC). Water and solvent controls were also included. Results indicated that, at 2x EEC, chlorothalonil significantly reduced the growth rate of enterococci compared to water, fertilizer, and malathion treatments. No other significant affects on growth rate were detected for the other bacteria.

Categories

Natural Sciences

Research Type

Thesis

Mentor Information

Dr. Valerie J. Harwood

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Effects of Agrochemicals on the Growth Rates of Bacterial Pathogens and Fecal Indicator Bacteria

Agricultural intensification in recent years has raised concern about the risks agricultural practices pose to human health. Waste from livestock, potentially containing zoonotic pathogens, can be contributed to water bodies via storm water and agricultural runoff. Additionally, agricultural runoff is likely to contain agrochemicals, such as fertilizers and pesticides. Understanding the impact these agrochemicals have on the growth of zoonotic pathogens and fecal indicator bacteria (FIB) is vital to improving agricultural and water management practices to safeguard public health. This experiment focused on the impact of agrochemicals on the growth rates of FIBs (Escherichia coli and Enterococcus faecalis) and agriculturally-derived pathogens (E. coli O157:H7 and Salmonella enterica) under nutrient-limited conditions. By isolating the bacteria from extraneous variables, such as competition and predation, potential direct effects of agrochemicals on growth rates could be identified. Agrochemical treatments consisted of inorganic fertilizer as well as the pesticides atrazine (herbicide), malathion (insecticide), or chlorothalonil (fungicide) at 1x and 2x expected environmental concentration (EEC). Water and solvent controls were also included. Results indicated that, at 2x EEC, chlorothalonil significantly reduced the growth rate of enterococci compared to water, fertilizer, and malathion treatments. No other significant affects on growth rate were detected for the other bacteria.