Leptotrichia species in human infections.

Leptotrichia species typically colonize the oral cavity and genitourinary tract. These anaerobic bacteria belong to the normal flora of humans and are seldom found in clinically significant specimens. However, on rare occasions, Leptotrichia has been isolated from blood cultures of patients with lesions in the oral mucosa, in particular from patients with neutropenia. These organisms should be considered potential pathogens in neutropenic patients, especially when breaks in the mucosal barriers are present through which they frequently spread to the bloodstream. Leptotrichia has also been recovered from immunocompetent persons, e.g. patients with endocarditis. Although their role in infections remains elusive and not much is known, they have been suggested as emerging pathogens. The present review deals with taxonomy, diagnosis, clinical importance, pathogenesis, host defence, infection control, and spectrum of Leptotrichia infections, and ends with a few typical case reports. Currently, six species have been validly published, but a number of yet uncultivable species exist. Molecular methods recovering uncultivable species should be used to get a real idea of their role as pathogens.

Leptotrichia buccalis: a rare cause of bacteraemia in non-neutropenic patients.

The anaerobic bacterium, Leptotrichia buccalis (Lb), belongs to the normal oral flora of humans and is seldom found in clinically significant specimens. However, on rare occasions, Lb has been isolated from blood cultures from patients with lesions of the oral mucosa, in particular from patients with neutropenia. Over a period of 6 months, Lb was isolated from blood cultures in our laboratory from 2 immunocompetent patients. The identification characteristics of Lb are described including the typical morphology at microscopy. Furthermore, we review the bacteraemic cases reported so far together with present knowledge of the pathogenicity and epidemiology of Lb.