Detection and Persistence of Clinical Escherichia coli in Drinking Water Evaluated by a Rapid Enzyme Assay and qPCR

The aims of this study were to evaluate two methods, qPCR and a chemiluminescent assay (ColiLight II), for rapid detection of E. coli in water, and to examine the survival and persistence of clinical E. coli in drinking water and biofilm using qPCR and ColiLight II. qPCR and ColiLight II were compared with a cultivation-based method (MPN), and survival and persistence of four clinical E. coli strains in water and biofilms on stainless steel (SS) and polyethylene (PE) surfaces were studied in a flow-through reactor with non-disinfected drinking water using ColiLight II, qPCR, ATP bioluminescence, and MPN. ColiLight II and qPCR correlated well with MPN. In drinking water, some clinical E. coli strains showed prolonged survival in drinking water flow-through systems, and persisted 3 3.4 times longer than the theoretical washout due to incorporation into biofilms. Strain specific attributes can significantly affect detection and persistence of E. coli in drinking water matrices.