Molecular fingerprinting of isolates of the genus Peptostreptococcus using rRNA genes from Escherichia coli and P. anaerobius.

Restriction fragment length polymorphisms (RFLPs) of rRNA genes were evaluated as a tool for intra- and interspecies differentiation of Peptostreptococcus isolates. RFLPs from a collection of 20 clinical isolates and five ATCC strains representing five Peptostreptococcus spp. (P. anaerobius, P. asaccharolyticus, P. magnus, P. micros and P. prevotii) were obtained by hybridization of Southern blots of HindIII- or EcoRI-digested genomic DNA with three probes: probe A, a 0.98 kb HindIII fragment with a partial 16S rRNA gene sequence from P. anaerobius ATCC 27337; probe B, cloned Escherichia coli rrnB operon in plasmid pKK3535; and probe C, E. coli 16S and 23S rRNA. The hybridization patterns varied, but all yielded RFLPs useful for both intra- and inter-species differentiation. RFLPs of P. asaccharolyticus clinical isolates were closely related to each other and differed significantly from those of the ATCC type strains. The profiles of P. prevotii differed from those of the other four species studied, and based on the HindIII- and EcoRI-generated RFLPs, the strains in this species are more heterogeneous than the other four species studied.