While completing a postdoctoral fellowship at the National Institutes of Health (NIH), Kiratisin noticed that standard methods used to identify members of the viridans group of streptococci did not always accurately distinguish between different species in this large group of bacteria, many of which cause endocarditis and other serious infections in humans. Moreover, more-sensitive molecular methods for identifying these organisms are not readily available outside of specialized laboratories. He hypothesized that identification of viridans group streptococci might be enhanced by using a technique known as housekeeping gene sequence analysis. Sequencing the glucose-6-phosphate dehydrogenase (gdh) and glucose kinase (gki) genes, he found, produced more accurate identification than either traditional biochemical techniques or sequence analysis of the 16S ribosomal DNA gene of these bacteria.
Kiratisin concluded that ghd/gki gene sequencing is a rapid and accurate means of identifying streptococcus species belonging to the mitis and sanguinis groups of viridans organisms. He also identified several reference strains of viridans group streptococci that had previously been misclassified. Clinical laboratories and physicians will both benefit from Kiratisin's innovative work; precise identification of viridans groups streptococci is particularly vital in treating infections caused by these organisms, some of which are resistant to antibiotics.
Contact: Barbara Hyde
American Society for Microbiology