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Development of a human-specific B. thetaiotaomicron IMS/ATP assay for measuring viable human contamination in surface waters in Baja California, Mexico
Citation:
Zimmer-Faust, A., V. Thulsiraj, L. Espinoza-Mendoza, AND J. Jay. Development of a human-specific B. thetaiotaomicron IMS/ATP assay for measuring viable human contamination in surface waters in Baja California, Mexico. 2016 Recreational Waters Conference, New Orleans, LA, April 12 - 15, 2016.
Impact/Purpose:
We developed a rapid method for detection of human-associated fecal contamination and applied it in surface waters of Baja California. This assay was effective at differentiating between waters that were impact and not impacted by local wastewater treatment facility effluent. This methods shows promise for rapidly evaluating contamination of recreational waters in areas where there is limited access to more expensive methods.
Description:
Immunomagnetic separation/adenosine triphosphate (IMS/ATP) assays utilize paramagnetic beads and target-specific antibodies to isolate target organisms. Following isolation, adenosine tri-phosphate (ATP) is extracted from the target population and quantified. An inversely-coupled (Inv-IMS/ATP)assay for detection of Bacteroides thetaiotaomicron was developed and applied for rapid detection of human-associated fecal contamination in surface waters in Baja California. Specificity of the assay was tested against challenge solutions of varying concentrations of dog, gull, horse and chicken feces, and a field validation survey of coastal and WWTP effluent water quality in Rosarito and Enseneda, Baja California was conducted. Inv IMS/ATP measurements made shown to be specific and sensitive to human fecal contamination. At test concentrations of less than 1000 MPN ENT/100 mL, sensitivity and specificity of the assay both exceeded 80%. Moreover, the Inv-IMS/ATP assay yielded measurements of viable B. thetaiotaomicron that were comparable to the HF183 human marker in complex surface waters impacted with both wastewater and runoff, and the Inv-IMS/ATP assay was able to effectively differentiate between surface waters impacted with adequately and inadequately treated wastewater. The Inv-IMS/ATP assays shows promise for rapid evaluation of recreational water quality in areas where access to more expensive methods is limited and in areas where water quality in unpredictable.