Identification of Photorhabdus asymbiotica in cases of human infection.

Photorhabdus asymbiotica is a potential cause of severe soft tissue and systemic infection in Australia. The clinical and laboratory features have been described in a recent publication.1 Recognition of this unusual pathogen presents a challenge for clinical microbiology laboratories. It is a bioluminescent gram-negative bacillus and is a member of the Enterobacteriaceae. It produces a thin zone of annular haemolysis on trypt ic soy agar containing either 5 per cent sheep or horse blood and tends to swarm.