Bilophila wadsworthia is an anaerobic, gram-negative, asaccharolytic, urease-positive, bile-resistant, catalase-positive bacillus, originally recovered from infections in patients with gangrenous and perforated appendicitis. Additional isolations from clinical specimens, including pleural fluid, joint fluid, blood and pus from a scrotal abscess, mandibular osteomyelitis and axillary hidradenitis suppurativa are described here. Bilophila is found as normal flora in feces and, occasionally, in saliva and in the vagina. Isolates from humans are usually beta-lactamase positive and therefore resistant to certain beta-lactam antibiotics. Two percent of strains are also resistant to clindamycin.