title: Amperometric quantification of total coliforms and specific detection of Escherichia coli.
abstract: The quantitative determination of total and fecal coliforms, as indicators of fecal pollution, is essential for water quality control. We developed a sensitive, inexpensive amperometric enzyme biosensor based on the electrochemical detection of beta-galactosidase activity, using p-amino-phenyl-beta-D-galactopyranoside as substrate, for determining the density of coliforms, represented by Escherichia coli and Klebsiella pneumoniae. The specific detection of E. coli was achieved using an antibody-coated electrode that specifically binds the target bacteria. Amperometric detection enabled the determination of 1000 colony-forming units/mL within 60-75 min. Preincubation for 5-6 h further increased the sensitivity more than 100-fold. The present experimental setup allowed the simultaneous analysis of up to eight samples, using disposable screen-printed electrodes.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat-Aviv, Israel.
authors.forename: Adrian Schwartz
authors.initials: AS
authors.lastname: Mittelmann
authors.forename: Eliora Z
authors.initials: EZ
authors.lastname: Ron
authors.forename: Judith
authors.initials: J
authors.lastname: Rishpon
mesh_terms: D000906:Antibodies / Q000737:chemistry; D015374:Biosensing Techniques; D004563:Electrochemistry; D004926:Escherichia coli / Q000737:chemistry* / Q000201:enzymology; D007711:Klebsiella pneumoniae / Q000737:chemistry; D014871:Water Microbiology; D014876:Water Pollution; D014881:Water Supply / Q000032:analysis; D001616:beta-Galactosidase / Q000032:analysis
chemical_list: D000906:Antibodies; D001616:beta-Galactosidase