Some serological studies on Bacteroides corrodens.

Bacteria currently known as Bacteroides corrodens and Eikenella corrodens have been described by Henriksen (1937), Henriksen (1948), Holm (I950), Eiken (1958), Reinhold (1966), Khairat (1967), Dowel1 & Hawkins (1968), Henriksen (1969), Hill, Snell & Lapage (I 9-70), Marsden & Hyde (I 97 I), Jackson, Goodman, Bel, Wong & Whitehouse (I 97 I), Wong & Jackson (1971) and Jackson & Goodman, (1972). Their most striking feature is the tiny pits in the surface of blood agar which they produce initially (Reinhold, 1966; Khairat, 1967). Failure to grow in the presence of oxygen led Eiken (1958) to name them Bacteroides corrodens. However, Henriksen (I 969) isolated oxygen-tolerant strains which showed a preference for microaerophilic conditions. The two types were shown to be biochemically unresponsive though not totally inert, morphologically similar, and manifested colonial forms which were indistinguishable one from the other. The dilemma which then arose was whether to allow the Bacteroides genus to claim the strictly anaerobic variety and consider its aerobic counterpart as more appropriate to the Haemophifus, or, if the pitting phenomenon were to be considered of paramount importance, to include them both in such a genus as would allow for the representation of both anerobic and aerobic species as in the case of Streptococcus. Jackson & Goodman (1972) proposed that a new genus, Eikenella, be created to accommodate the facultatively anaerobic strains, and that the strictly anaerobic strains be excluded from the Bacteroides. These recommendations were based mainly on the considerable differences in their GC ratios (28 to 30 yo for strictly anaerobic strains as against 57 to 58 yo for facultative strains), and lack of any demonstrable serological relationship between strictly anaerobic and facultatively anaerobic strains (Jackson et al. 1971 ; Wong & Jackson, 1971 ; Jackson & Goodman, 1972). Failure to show such a relationship was possiblyidue to the limited number of anaerobic strains they tested. In this study a number of strictly anaerobic strains and facultatively anaerobic strains of B. corrodens are compared serologically with several species of Bacteroides and Haemoph ilus.