Rapid identification of Abiotrophia/Granulicatella species by 16S rRNA-based PCR and RFLP

Abstract

Abiotrophia/Granulicatella species formerly known as nutritionally variant oral streptococci now consist of five species, Abiotrophia defectiva, Granulicatella adiacens, Granulicatella elegans, Granulicatella para-adiacens and Granulicatella balaenopterae. In this study, a rapid and highly sensitive identification method for the five Abiotrophia/Granulicatella species was developed. The developed method combines the species-specific PCR assays targeting 16S rRNA genes and the 16S rRNA gene PCR amplification followed by a restriction fragment length polymorphism analysis (PCR-RFLP). The species-specific PCR assays enabled to detect exclusively A. defectiva, G. elegans and G. balaenopterae with high sensitivities of 5 pg of genomic DNA, and showed high specificities. However, G. adiacens and G. para-adiacens cannot be distinguishable each other by a simple PCR assay. Then, the PCR-RFLP with BsmI was developed for the detection of G. adiacens and G. para-adiacens, which also yielded highly sensitive and specific identification of these two species.