Does exposure to chemical pollutants from anthropogenic activities increase pathogenic virulence ?

Kartik Chandran (Associate Professor, EEE)

To achieve sustainable development in the world, we need to ensure adequate quality of one of our cardinal resources - our potable water supply. Currently, 10 million children die annually, mostly from preventable diseases. For the millions of cases of childhood mortality each year, the second highest cause is diarrhea from pathogen contaminated water supplies (3). Although considerable research has been devoted to tracking sources of fecal coliform contamination in the environment, a significant gap still exists in understanding how human pathogenic strains of enteric bacteria survive in the environment compared to non-pathogenic strains. As a first step in preventative child health care, knowledge on the spread and diversity of pathogens in the environment is vital.

Another threat to water quality in developing countries is the increased discharge of toxic wastes in urban waterways. These wastes induce bacterial stress responses in the natural microbial populations. There is emerging anecdotal evidence that prior exposure to stress can lead to increased pathogenicity and antibiotic resistance. Further, diversity decreases in microbial communities can also result from exposure to environmental toxicants. This decrease in natural environmental diversity may increase the ability of pathogens to survive. Studies on diversity within hosts show an increase in pathogens as the microbial diversity is decreased. In this context, it is important to examine the pathogenicity of bacteria subject to chemical exposure from both urban and rural environments.

The scholarly research described here is one of the few known attempts to quantify virulence factors in bacteria as a result of exposure to prior chemical pollutants and interactions with eukaryotic organisms.

We employ state-of-the-art molecular biology and genomics based tools for in-situ detection methods of pathogen stress and virulence. Techniques include multiplex polymerase chain reaction (PCR) to determine multiple virulent factors present in a single sample, coupled with fluorescent in-situ hybridization (FISH) to detect bacteria in the environment.

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