Grantee Research Project Results
2001 Progress Report: Mycobacterium avium Complex in Drinking Water: Detection, Distribution, and Routes of Exposure
EPA Grant Number: R828036Title: Mycobacterium avium Complex in Drinking Water: Detection, Distribution, and Routes of Exposure
Investigators: Ford, Timothy E.
Institution: Harvard University , Montana State University
EPA Project Officer: Hahn, Intaek
Project Period: (Extended to March 21, 2004)
Project Period Covered by this Report: January 1, 2001 through January 1, 2002
Project Amount: $516,679
RFA: Drinking Water (1999) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
The objectives of this research project are to: (1) develop improved methods for detecting Mycobacterium avium complex (MAC) in biofilms; (2) explore and implement more sensitive techniques for the detection of MAC in drinking water samples; and (3) determine the prevalence of MAC in municipal drinking water distribution systems and at sites of end user exposure (drinking water, hot water, and toilet tank water).
Progress Summary:
The work as it stands has fallen into three main areas:
(1) Hot-water recirculating bypass system-generating environmental biofilm samples for MAC detection, biofilm formation, and survival studies.
(2) MAC florescence in situ hybridization (FISH) probe development and testing-to provide a more accurate and reliable method for detection and quantification of MAC in drinking water.
(3) MAC prevalence and end-user exposure survey-collection and analysis (MAC and various water quality parameters) of drinking water and biofilm samples from distribution systems and residential homes in four eastern Massachusetts towns (145 sites are being sampled monthly for the period of 1 year).
We have made considerable progress in all three areas. Our original aims have not changed, but the research has led us to pursue certain methods more rigorously. For example, the FISH probe development has been a major focus area, as this technique is widely accepted as an extremely accurate method in the detection and visualization of specific bacterial species. The use of FISH for detection of bacteria residing in biofilms now is commonly used, but no probe has yet been developed for MAC. Due to the unique nature of the mycobacterial cell wall, various groups have had only limited success in developing an effective FISH probe for any mycobacterial species. We are confident that our FISH probe and modified protocols will provide a new tool in evaluating MAC in environmental samples.
Samples for biofilm analysis have been collected from the bypass system on two different occasions. The results of the biofilm samples harvested show the presence of MAC in the biofilm, which was confirmed by isolation and subsequent PCR typing. This is the first time a system of this type has been used to investigate and show mycobacterium growth in biofilms. At least 20 different MAC strains have been isolated from bypass biofilm samples. Using restriction fragment length polymorphism (RFLP), we currently are investigating whether the MAC clones isolated from water samples are similar to those from biofilms.
We now have completed almost 2 months of water and biofilm sample collections from the field. In total, over 200 samples have been collected and processed, and these initial data currently are being reviewed. This type of systematic drinking water and biofilm sampling for the evaluation of MAC end-user exposure has never been conducted for any municipality.
Future Activities:
Future activities for this research project are to:
(1) Install bypass system II.
(2) Conduct FISH probe testing on biofilm samples from bypass system I and residential home biofilm slide samplers. These samples will be viewed using an epi-florescence microscope equipped with a high-resolution digital camera and quantified using sophisticated image analysis software.
(3) Continue monthly water and biofilm sampling from 145 sites across the 4 eastern MA towns for 10 more months to complete the 1-year intensive MAC drinking water exposure survey.
(4) Continue to formulate at least two parallel manuscripts of our findings, which we hope to submit for publication, back to back, in a leading peer-reviewed journal.
Journal Articles:
No journal articles submitted with this report: View all 6 publications for this projectSupplemental Keywords:
pathogens, survival, proliferation, new techniques, mycobacteria, morphotypes, florescence in situ hybridization, biofilm, hot water recirculating systems, bypass systems, water distribution systems, end-user exposures, geographical information system, GIS., RFA, Scientific Discipline, Water, Environmental Chemistry, Health Risk Assessment, Environmental Microbiology, Environmental Monitoring, Ecological Risk Assessment, Drinking Water, alternative disinfection methods, monitoring, CCL, detection, water quality parameters, exposure and effects, mycobacterium avium complex, routes of exposure, exposure, community water system, treatment, emerging pathogens, microbial exposure, water quality, contaminant removal, drinking water contaminants, drinking water treatment, water treatment, contaminant candidate list, DNA microarraysRelevant Websites:
http://www.hsph.harvard.edu/water Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.