RII Track-4: NSF: Insights into Pathogenicity of Chlorine-Stressed Bacteria Using Combined In Vitro Assays and Metatranscriptomics

New Mexico State University, Las Cruces NM

Investigators

Abstract

Bacterial pathogens in water pose a significant worldwide threat to public health, especially for individuals with weakened immune systems. Currently, chlorination is the most widely used water disinfection process to cause the inactivation of microorganisms in the water to ensure public and environmental health. While most bacteria in water can be effectively killed after chlorination, some may survive due to their resistance to disinfectants. There has yet to be a comprehensive study to investigate the ability of the surviving bacteria to infect a host and cause disease. This Research Infrastructure Improvement RII Track-4 fellowship project will explore the impact of water disinfection on the pathogenicity of bacteria, which will help overcome the current knowledge gap regarding microbial risk assessment after water treatment. This goal will be addressed by using advanced cellular tools and next-generation sequencing techniques developed at the host site, the Biological Measurements Branch of the US Environmental Protection Agency. The fundamental knowledge obtained from this project is expected to provide valuable information to stakeholders and policymakers for reassessing the current water treatment processes and reducing health risks. This research will also offer training opportunities for underrepresented students at New Mexico State University, which is an Hispanic-Serving Institution. This Research Infrastructure Improvement Track-4 EPSCoR Research Fellows (RII Track-4) proposal would provide a fellowship to an Assistant Professor and training for a graduate student at New Mexico State University. This work would be conducted in collaboration with researchers in the Biological Measurements Branch of the Watershed & Ecosystem Characterization Division at the United States Environmental Protection Agency (EPA) in Cincinnati, OH. Knowing if the surviving bacteria after disinfection still hold their initial characteristics, especially pathogenicity, is essential. There is a possibility that inappropriate chlorination may stimulate the pathogenicity of surviving bacteria due to the induced transcription of gene encoding virulence, reactive oxygen species (ROS) response, or horizontal transfer of virulence genes. This project aims to better understand the pathogenicity of surviving microorganisms after chlorination by investigating host-bacteria interactions. Specifically, this project aims to: 1) Investigate the tolerance of chlorine-stressed bacteria under simulated gastrointestinal conditions; 2) Examine the adhesion and invasion of chlorine-stressed bacteria to human intestinal epithelial cells; 3) Compare the inflammatory responses of cells under exposure to non-stressed and chlorine-stressed bacteria; 4) Determine the changes in virulence gene expression using multiple qPCR arrays; and 5) Elucidate cellular response of chlorine-stressed bacteria to chlorine through genome-wide transcriptional analysis. The expected outcomes of this fellowship project will facilitate the development of novel disinfection strategies to reduce the pathogenicity of surviving bacteria and minimize the spread of bacteria with pathogenicity into the water distribution system. The methods developed in the proposed study could be expanded to the fields of food preservation and medical disinfectants. The support from the EPSCoR RII Track-4:NSF program will allow the PI's institution to advance its research capacity and establish collaboration networks with EPA. It also provides a foundation for building the PI's research program into a significant and regular contributor to pathogen removal in water systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.