Detection and identification of species with bacterial cells using a plastic DNA array

The rapid identification of bacteria in many kinds of samples, i.e., clinical, food, water, and material, is important from a hygienic standpoint. In this paper, we describe the development of a convenient bacterial identification system using bacterial cells by a plastic DNA array. The small plastic base, which was cut from an S-BIO((R)) PrimeSurface((R)) plastic base developed for the covalent immobilization of amino-modified DNA, was used as a substitute for a glass base. The species-specific primers were immobilized on the small plastic base and the spots specific to each bacterial species were observed after 2 types of thermal cycles in a single PCR tube using bacterial culture broth as a sample. The results obtained using the culture broth were the same as those obtained with total DNA extracted from bacterial cells. The detection limits of Staphlococcus aureus (S. aureus) ATCC25923 and Escherichia coli (E. coli) ATCC25922 were 8.7 x 10(3) cells/mu l and 2.1 x 10(2) cells/pl, respectively. This system is useful and convenient for the identification of bacteria in many types of samples. Moreover, further improvements in conditions, such as the ingredients in the reaction mixture, thermal cycles, and the steps of visualization would result in a more efficient system of identification.