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

This study compared the potential of three techniques to differentiate betw een the species Prevotella intermedia (ATCC 25611) and Prevotella nigrescen s (ATCC 33563, ATCC 25261) including recent clinical isolates identified on ly as P. intermedia using Rapid ID 32A. The techniques used were: RAPD-PCR (random amplification of polymorphic DNA by polymerase chain reaction) usin g the arbitrary primer L10, partial 16S rRNA gene sequencing using general bacterial primers TPU1 and RTU3, and PCR with species specific oligonucleot ide primers designed to regions of the 16S rDNA chosen by analysis of the f ull 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 het erogeneity, clinical isolates can be identified as P. intermedia or P. nigr escens by this method. Partial 16S rRNA sequencing and species specific PCR are easily accessible with molecular information readily available. Specif ic PCR requires time-consuming optimisation but may be the technique of cho ice for clinical samples. It is concluded that all techniques are appropria te but that no one technique would be best for all applications. (C) 1999 A cademic Press.