Objective To set up a rapid and simple method for identificating bacteria by 16S 23SrDNA intergenic spacer regions (ISRs) Methods Polymorphic products of PCR from ISRs were selected on agarose gel and sequenced directly using purified fragments by excising the gel without cloning Nucleotide sequences were compared with GenBank databases and analyzed by DNAMAN program Results There was only a single product in streptococcus genus after PCR amplification of 16S 23SrDNA ISRs Five streptococcal species were obtained from 7 strains of streptococcus Two major amplicons were consistently generated for 8 strains of Haemophilus influenzae (H influenzae) The sequence data showed that they all belonged to H influenzae type b on GenBank databases Conclusion PCR and direct sequencing of 16S 23SrDNA ISRs were very successful methods for bacterial species identification
