“…Pectinatus species, along with Selenomonas, Megasphaera, Sporomusa, Veillonella and Zymophilus, belong to the Sporomusa subbranch of the Clostridium subphylum of Gram-positive bacteria (Schleifer et al, 1990;Willems and Collins, 1995). Moreover, Pectinatus species have been classified as relatives of Gram-negative, anaerobic bacteria such as Centipeda periodontii (Sawada et al, 1999), Dialister pneumosintes (Willems and Collins, 1995), Schwarzia succinivorans (Van Gylswyk et al, 1997), Acidaminococcus fermentans (Both et al, 1992) and some Anaerovibrio species (Strömpl et al, 1999). According to the 16S rRNA sequences, the similarity between P. frisingensis and P. cerevisiiphilus was 95%, the nearest other species (similarities with Pectinatus spp.)…”