BACKGROUND: Wohlfahrtiimonas chitiniclastica is a rarely reported cause of bacterial infection associated with skin lesions and sepsis. It has been isolated in nonbiting flies that can cause myiasis (fly larvae infestation); however, it has neither been isolated from fly larvae on patients with W. chitiniclastica infection, nor from insects in the Americas. In August 2016, a man was hospitalized in Washington State with necrosis of the foot, myiasis, and Wohlfahrtiimonas spp. bacteremia. We investigated to determine exposure source.
METHODS: We attempted to collect live and dead insects (including fly eggs and larvae) from the patient and patient’s home and culture them for Wohlfahrtiimonas spp. at different lifecycle phases. Pulsed-field gel electrophoresis (PFGE) was performed on isolates to assess relatedness. Recent patient travel history was obtained through proxy interviews.
RESULTS: We collected 8 insect species from inside the patient’s home. Although larvae present on the patient when hospitalized were unavailable for testing, Wohlfahrtiimonas spp. was isolated from larvae collected from the carpet where the patient was found by emergency responders. These larvae were not taxonomically identified. Wohlfahrtiimonas spp. was also isolated from larvae hatched from eggs of a green bottle fly (Lucilia sericata) caught inside the home. PFGE results are pending. No travel outside of Washington was reported.
CONCLUSIONS: We report the first isolation of Wohlfahrtiimonas spp. in insects in the Americas and a previously undescribed vector, the green bottle fly. Our investigation provides further evidence of fly larvae as vectors for human infection. Green bottle fly larvae are a common cause of myiasis; patients with myiasis should be considered at risk for Wohlfahrtiimonas spp. infection.