Monitoring Pathogens in Water Systems

Rationale and Significance: The prevention of infectious disease from exposure to contaminated food, water, and air remains a major task for environmental health workers. Despite substantial efforts to ensure the safety of water supplies, outbreaks of infectious waterborne illnesses continue. The USA has an average of 4 reported outbreaks of infectious diseases affecting perhaps 10,000 people per year due to deficiencies in community water systems [Haas et al., 1999]. It has been estimated that nearly one-fourth of all hospital beds in the world are occupied by patients with complications arising from infection by waterborne organisms [Gerba, 1996]. Human enteric viruses are believed to be the major cause of foodborne disease in the United States [Gerba and Kayed, 2003], causing up to 67% of all cases [Mead 1999]. Produce is the second most common food item associated with foodborne illness in the Unites States and has been on the increase in recent years. Human caliciviruses are now believed to be the major cause of foodborne illness in the United States [Gerba and Kayed, 2003] and are estimated to be responsible for 40% of all cases of food borne illness. Methods for detecting microbial agents that cause disease typically involve extensive laboratory analyses that require from many days to several weeks to perform. This time is not suitable for early diagnostic and preventative purposes to ensure the safety of the water or food supply. Methods are needed that work much more quickly but still provide high specificity for certain organisms and provide an ability to quantify small amounts of potentially hazardous materials. There is no single method to analyze a water or food sample for the variety of pathogenic microorganisms of concern. Some of the difficulties in developing such a universal method include physical and biochemical differences between the major pathogen groups (viruses, bacteria, protozoa), the presence of compounds that inhibit the reverse transcriptase utilized in PCR, and the long times required for analysis through traditional microbiological techniques [Straub and Chandler, 2003]. Such problems limit our capabilities for monitoring high volume materials such as domestic drinking water for the presence of potentially pathogenic materials. There are a number of new commercial sensors with promise for continual monitoring, however, they have not been fully tested and vetted in an independent manner such that performance capabilities can be compared.
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NON-TECHNICAL SUMMARY: The prevention of infectious disease from exposure to contaminated food, water, and air remains a major task for environmental health workers. Despite substantial efforts to ensure the safety of water supplies, outbreaks of infectious waterborne illnesses continue. The USA has an average of 4 reported outbreaks of infectious diseases affecting perhaps 10,000 people per year due to deficiencies in community water systems [Haas et al., 1999]. It has been estimated that nearly one-fourth of all hospital beds in the world are occupied by patients with complications arising from infection by waterborne organisms [Gerba, 1996]. Produce is the second most common food item associated with foodborne illness in the Unites States and has been on the increase in recent years. Methods for detecting microbial agents that cause disease typically involve extensive laboratory analyses that require from many days to several weeks to perform. This time is not suitable for early diagnostic and preventative purposes to ensure the safety of the water or food supply. Methods are needed that work much more quickly but still provide high specificity for certain organisms and provide an ability to quantify small amounts of potentially hazardous materials. There is no single method to analyze a water or food sample for the variety of pathogenic microorganisms of concern. Current technical problems limit our capabilities for monitoring high volume materials such as domestic drinking water for the presence of potentially pathogenic materials. There are a number of new commercial sensors with promise for continual monitoring, however, they have not been fully tested and vetted in an independent manner such that performance capabilities can be compared. Objectives. The overall objectives of this project are to develop and evaluate methods for detection of pathogenic organisms in drinking water systems. This objective will be met by addressing the following specific aims: Aim 1: Develop method to quantify the presence of infective materials. Aim 2: Evaluate commercial and developing technologies for continual monitoring of water systems for the presence of microorganisms. Outcomes / impacts. The likely outcome of this work is the development of new methods that can detect pathogens in water. This fills an important niche between continual monitoring methods and time intensive laboratory work. The impact could be substantial in preventing and diagnosing the presence of active viral material in water and other systems.

<P>APPROACH: To meet the objectives of this project will require significant progress in instrumentation development, applied microbiology, and real world testing. To address the first aim, we will build on our prior work to develop cell culture infrared spectroscopic measurements. This approach, described in more detail below, provides a means to quantify and differentiate between chemical and biological toxicants in water systems based on the response of a sacrificial cell layer. The cells are probed by infrared light which does not damage cell components, but rather provides a means to search for changes in cell physiology and function. We have used this approach to detect inhalation health hazards. Focus here will be on detecting infective viral particles and other related biological compounds. To address the second aim, we shall continue to construct and test a real-time testing facility for water monitoring utilizing a variety of commercial sensors operating in parallel such that injections of microorganisms can be delivered to each sensor at the same time. This allows rigorous testing of sensing performance capabilities, limits of detection, and sensitivity to interfering factors. This facility is under construction at the Environmental Research Laboratories at the UA's Water Village, approximately 10 miles south of main campus. The facility is unique in its design and capabilities and has been developed with significant support from our local water provider, Tucson Water