Isolation of Bacteroides corrodens and Eikenella corrodens from human clinical specimens. Comparative study of incidence and methods of identification.

In the course of a systematic search for Bacteroides corrodents and Eikenella corrodens in clinical specimens submitted for microbiological analysis, 61% of the specimens from anal abscesses, 6% of the vaginal specimens and none of the pharyngeal specimens yielded B. corrodens, whereas E. corrodens was recovered from only 9% of the pharyngeal specimens. Some characteristics were found to be useful in differentiating between the two species: B. corrodens strains were strictly anaerobic, cytochrome-oxidase-negative, urease-positive and gelatinase-positive; they were sensitive to lincomycin but resistant to vancomycin. E. corrodens strains on the other hand were facultatively anaerobic, oxidase-positive, urease-negative and gelatinase-negative; they were resistant to lincomycin but sensitive to vancomycin. The pathogenicity of the two species was difficult to assess as in most cases they were recovered from mixed cultures.