A Device to Rapidly Detect Coliform Bacteria and Escherichia Coli in Field Water Samples

A new rapid (<8h), sensitive (1 CFU/100ml) and simple phage-based method will be developed for detection of Escherichia coli and total coliforms in contaminated water. The system termed QUICC (QUantification and Identification of Coliform Contamination) utilizes a combination of filtration to capture the bacteria and a genetically engineered temperate lacZ reporter phage which overexpresses -galactosidase in infected cells. Enzyme levels emanating from endogenous bacterial-encoded and phage-encoded -galactosidase leads to signal amplification following addition of a fluorescently-labeled substrate. As QUICC is designed to enhance the key rate-limiting factor associated with most water detection methods, it will be compatible and readily adaptable to EPA-approved systems. QUICC methodology involves capture of target bacteria on a syringe filter unit (pre-concentration), resuspension of the captured target bacteria in elution buffer (growth medium with additives), incubation with the reporter phage for amplification of the enzyme and following substrate addition, fluorescent detection with a handheld fluorometer. This system is simple and portable and only detects viable bacteria capable of producing the enzyme. This reporter phage-based system integrated with EPA-approved detection methods for bacteria will have specific advantages over other detection technologies in terms of more rapid detection and lowered sensitivity limits of detection.