Transfer of the Facultatively Anaerobic Organism Bacteroides corrodens Eiken to a New Genus, Eikenella

Abstract

It is proposed that the facultatively anaerobic, gram-neptive organism described by Eiken (1958) and named by him Bacteroides corrodens be transferred to a new genus, which the authors name Eikenella. Organisms of this kind form a fairly homogeneous group and differ in important respects from the generally accepted Bacteroides species and from the members of the currently recognized genera of the family Brucellaceae, wherein the genus Eikenella is placed. An up-dated description of the type species, E. corrodens (Eiken) comb. n. (basionym: B. corrodens Eiken 1958), is given. The type strain of this species, previously designated by Henriksen, is Henriksen's strain 333/54-5 5 (ATCC 23834; NCTC 10596), one of the strains originally studied by Eiken.Certain gram-negative "corroding bacilli" have been subjected to detailed investigation during the past few years (2, 5 , 6), and they appear not t o fit easily into any of the currently recognized genera. Organisms of this type were examined by Eiken ( l ) , who placed them in the genus Bacteroides, under the name B. corrodens, because most of the strains with which he worked either were anaerobic or adapted to aerobic growth only after a number of subcultures. More recent work (6) has shown that the aerobic growth of these organisms may be dependent on the constitution of the medium, particularly on the hemin content. Moreover, the moles per cent guanine plus cytosine (GC) content of the deoxyribonucleic acid (DNA) of all strains tested lies in the 57 to 58 range, and this is widely different from the value for the accepted Bacteroides species. Prkvot (9), who does not accept the validity of the generic name Bacteroides but uses the name Ristella, states that members of the genus have an adenine plus thymine t o GC ratio of 1.4, which is equivalent to a GC content of 41%. Similar values for members of the genus Bacteroides have been quoted by Hill (4). Strains of B. fragilis (42.2%) and B. melaninogenicus (41%) that we have examined gave values close to this figure.The purpose of this paper is t o designate a new genus t o contain the facultatively anaerobic strains of the type t o which Eiken gave the name B. corrodens.

Chromobacterium, Eikenella, Kingella, Neisseria, Simonsiella, and Vitreoscilla Species Comprise a Major Branch of the Beta Group Proteobacteria by 16S Ribosomal Ribonucleic Acid Sequence Comparison: Transfer of Eikenella and Simonsiella to the Family Neisseriaceae (emend.)

“…Our results indicate that Eikenella corrodens is a genetically homogeneous species, in agreement with the results of previous DNA-DNA hybridization studies (7) and genetic transformation studies (60). The genus Eikenella was proposed by Jackson because he realized that the species "Bacteroides corrodens" did not belong in the genus Bacteroides (17). From Figure 2, it is evident that Eikenella corrodens is more closely related to Kingella denitrificans than Kingella kingae is.…”

In Vitro Susceptibility of Bacteroides corrodens and Eikenella corrodens to Ten Chemotherapeutic Agents

“…Similarly, the high MBC of chloramphenicol (> 100 ,g/ml) in relation to MIC (2.0 ig/ml) for group NC-I compared with that of NCL-20 (MIC, 6.9 jig/ml; MBC, 15.4 jig/ml) and the relative resistance of group NCL-20 to demethylchlortetracycline compared with NC-I could indicate essential differences between these groups.…”

Characterization of a beta-lactamase found in Eikenella corrodens

“…It is a normal inhabitant of the oral cavity and upper respiratory tract (15) and is frequently found in dental plaque (12) and periodontal lesions (30). The organism has been associated with endocarditis and bacteremia following dental manipulations (10,18) and may be implicated in the initiation and/or progression of certain destructive periodontal disease syndromes (38,39).…”