[Rapid identification of Bilophila wadsworthia]

Biophila wadsworthia is a recently recognized nonspore-forming anaerobic gram-negative rod and is reported to be associated with various infections such as gangrenous perforated appendicitis, peritonitis, osteomyelitis and bacteremia. Although the isolation of B. wadsworthia seems to be facilitated by using Bacteroides bile esculin (BBE) agar, the reliable scheme of identification of this species has been published. This study was conducted to find simple, rapid, and reliable measures for identification of B. wadsworthia. A total of 32 B. wadsworthia-suspected clinical isolates as well as B. wadsworthia WAL 7959 and Desulfomonas pigra DSM 749, which is the species that shows bacteriological characteristics similar to B. wadsworthia, were used. Through the study of various biochemical and enzymatic tests and culture on selective media, it is indicated that a nonspore-forming, gram-negative anaerobic rod that is nonmotile, forms "black-eyed" colonies on BBE agar, and demonstrates strongly positive catalase test, positive acid phosphatase test, and no-growth on Bacterides medium or to be susceptible to colistin (10 micrograms disk) can be identified as B. wadsworthia.