Abstract
Development of rapid molecular approaches for pathogen detection is key to improving treatment of infectious diseases. For this study, the kinetics and temperature-dependence of DNA probe hybridization to uropathogen species-speciWc sequences were examined. A set of oligonucleotide probes were designed based on variable regions of the 16S gene of the Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, and Pseudomonas aeruginosa. A universal bacterial probe and probes-speciWc for gram-positive and gram-negative organisms were also included. The oligonucleotide probes discriminated among 16S genes derived from 11 diVerent species of uropathogenic bacteria applied to nylon membranes in a dot-blot format. SigniWcant binding of oligonucleotide probes to target DNA and removal of nonspeciWc binding by membrane washing could both be achieved rapidly, requiring as little as 10min. An oligonucleotide probe from the same species-speciWc region of the E. coli 16S gene was used as a capture probe in a novel electrochemical 16-sensor array based on microfabrication technology. Sequence-speciWc hybridization of target uropathogen 16S rDNA was detected through horseradish peroxidase acting as an electrochemical transducer via a second, detector probe. The sensor array demonstrated rapid, species-speciWc hybridization in a time course consistent with the rapid kinetics of the dot-blot hybridization studies. As in the dot-blot hybridization studies, species-speciWc detection of bacterial nucleic acids using the sensor array approach was demonstrated both at 65°C and at room temperature. These results demonstrate that molecular hybridization approaches can be adapted to rapid, room temperature conditions ideal for an electrochemical sensor array platform. Published by Elsevier Inc.