B.S. (Agriculture), University of Agricultural Sciences, Bangalore, India, 1979
M.S. (Agricultural Microbiology), University of Agricultural Sciences, Bangalore, India, 1982
M.S. (Microbiology), University of Hawaii at Manoa, Honolulu, Hawaii, 1996
Ph.D. (Environmental Microbiology), University of Hawaii at Manoa, Honolulu, Hawaii, 2000
Escherichia coli (E. coli) and enterococci occurrence in nonenteric habitats (e.g., soil, vegetation) has been documented since the early 1960s. While the original source of these bacteria remains speculative, recent studies show that populations of E. coli and enterococci are genetically different from those that are commonly found in the gastrointestinal tract of humans. The ability of these bacteria to survive and grow under ambient conditions, as shown in numerous studies, has led many to believe that some human bacterial pathogens with comparable physiology and genetics (of E. coli) (e.g., Salmonella, pathogenic E. coli strains) can similarly survive and may even grow in nonenteric habitats. Thus, a clear understanding of the population structure, genetic relatedness and potential sources of E. coli and other enteric bacteria is especially critical to correctly identify contaminant sources, to determine if there were any ecological roles (e.g., organic matter decomposition, plant protection from pathogens) for these enteric bacteria in soil or other habitats, and importantly to protect the public from exposure to harmful pathogens in contaminated waters.
There is growing evidence that fecal indicator bacteria (FIB; E. coli, enterococci) that are routinely used as pathogen indicators in environmental waters are also found in nonenteric habitats. Therefore, understanding their ecology (i.e., survival, persistence, and ambient growth) in nonenteric habitats is critical for correctly identifying contaminant sources, improving predictive modeling, developing new or improved criteria, and identifying and quantifying risk, as well as protecting the public from potential exposure to harmful pathogens in environmental waters.
Several studies have shown that Cladophora mats are a source of enteric human bacterial pathogens (e.g., Salmonella, Campylobacter), potentially influencing shoreline water quality and affecting swimmers health. Equally concerning is the recent hypothesis that Cladophora may have a role in the spread of botulism disease in fish-eating birds of the Great Lakes. A high incidence of botulism in birds parallels with increased Cladophora accumulations in shoreline waters. However, Cladophora role in this disease pathway remains to be elucidated. Moreover, quantifiable (i.e., measurable) health risk to humans or wildlife from direct exposure to Cladophora or Cladophora-laden water/contaminated beach sand deserves further investigation.