A comparison of techniques used to distinguish strains of Prevotella intermedia from Prevotella nigrescens

This study compared the potential of three techniques to differentiate between the species Prevotella intermedia (ATCC 25611) and Prevotella nigrescens (ATCC 33563, ATCC 25261) including recent clinical isolates identified only as P. intermedia using Rapid ID 32A. The techniques used were: RAPD-PCR (random amplification of polymorphic DNA by polymerase chain reaction) using the arbitrary primer L10, partial 16S rRNA gene sequencing using general bacterial primers TPU1 and RTU3, and PCR with species specific oligonucleotide primers designed to regions of the 16S rDNA chosen by analysis of the full sequences as available in the EMBL database. Cluster analysis of binary matrix data from RAPD-PCR fingerprints confirmed that P. intermedia and P. nigrescens are genetically distinct and although there is intraspecies heterogeneity, clinical isolates can be identified as P. intermedia or P. nigrescens by this method. Partial 16S rRNA sequencing and species specific PCR are easily accessible with molecular information readily available. Specific PCR requires time-consuming optimisation but may be the technique of choice for clinical samples. It is concluded that all techniques are appropriate but that no one technique would be best for all applications. (C) 1999 Academic Press.