Traditional and molecular analyses for fecal indicator bacteria in non-point source subtropical recreational marine waters

Christopher D. Sinigalliano, Jay M. Fleisher, Maribeth L. Gidley, Helena M. Solo-Gabriele, Tomoyuki Shibata, Lisa R.W. Plano, Samir M. Elmir, David Wanless, Jakub Bartkowiak, Rene Boiteau, Kelly Withum, Amir M. Abdelzaher, Guoqing He, Cristina Ortega, Xiaofang Zhu, Mary E. Wright, Jonathan Kish, Julie Hollenbeck, Troy Scott, Lorraine C. BackerLora E. Fleming

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

The use of enterococci as the primary fecal indicator bacteria (FIB) for the determination of recreational water safety has been questioned, particularly in sub/tropical marine waters without known point sources of sewage. Alternative FIB (such as the Bacteroidales group) and alternative measurement methods (such as rapid molecular testing) have been proposed to supplement or replace current marine water quality testing methods which require culturing enterococci. Moreover, environmental parameters have also been proposed to supplement current monitoring programs. The objective of this study was to evaluate the health risks to humans from exposure to subtropical recreational marine waters with no known point source. The study reported symptoms between one set of human subjects randomly assigned to marine water exposure with intensive environmental monitoring compared with other subjects who did not have exposure. In addition, illness outcomes among the exposed bathers were compared to levels of traditional and alternative FIB (as measured by culture-based and molecular-based methods), and compared to easily measured environmental parameters. Results demonstrated an increase in self-reported gastrointestinal, respiratory and skin illnesses among bathers vs. non-bathers. Among the bathers, a dose-response relationship by logistic regression modeling was observed for skin illness, where illness was positively related to enterococci enumeration by membrane filtration (odds ratio = 1.46 [95% confidence interval = 0.97-2.21] per increasing log10 unit of enterococci exposure) and positively related to 24 h antecedent rain fall (1.04 [1.01-1.07] per increasing millimeters of rain). Acute febrile respiratory illness was inversely related to water temperature (0.74 [0.56-0.98] per increasing degree of water temperature). There were no significant dose-response relationships between report of human illness and any of the other FIB or environmental measures. Therefore, for non-point source subtropical recreational marine waters, this study suggests that humans may be at increased risk of reported illness, and that the currently recommended and investigational FIB may not track gastrointestinal illness under these conditions; the relationship between other human illness and environmental measures is less clear.

Original languageEnglish (US)
Pages (from-to)3763-3772
Number of pages10
JournalWater Research
Volume44
Issue number13
DOIs
StatePublished - Jul 2010
Externally publishedYes

Bibliographical note

Funding Information:
This Epidemiology Proposal was funded in part from the following sources: the National Center for Environmental Health (NCEH) , Centers for Disease Control and Prevention (CDC); Florida Dept of Health (FL DOH) through monies from the Florida Dept of Environmental Protection (FL DEP); the Environmental Protection Agency (EPA) Internship Program ; the National Science Foundation (NSF) and the National Institute of Environmental Health Sciences (NIEHS) Oceans and Human Health Center at the University of Miami Rosenstiel School [ NSF 0CE0432368/0911373 ] and [ NIEHS P50 ES12736 ] and NSF REU in Oceans and Human Health, and the NSF SGER [ NSF SGER 0743987 ] in Oceans and Human Health . Development of the dog-host-specific Bacteroides qPCR assay was funded in part by the Northern Gulf Institute , a NOAA Cooperative Institute (NOAA’s Office of Ocean and Atmospheric Research, U.S. Department of Commerce award NA06OAR4320264 ). In addition, we would like to thank Source Molecular Corporation (Miami, FL) for supplies and logistic support for the development of the gull-host-specific Catellicoccus qPCR assay. We would also like to thank IDEXX Corporation for their support of our project through the provision of supplies needed for the chromogenic substrate analysis of enterococci.

Keywords

  • Bacteroidales
  • Chromogenic substrate
  • Enterococci
  • Gastrointestinal illness
  • Indicator organisms
  • Membrane filtration plate counts
  • Quantitative PCR
  • Recreational water quality
  • Respiratory illness
  • Skin illness

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