Clustering of bloodstream infections during maggot debridement therapy using contaminated larvae of Protophormia terraenovae

Abstract

Background: The treatment of human wounds with fly larvae is an ancient procedure recently reintroduced into medical practice under the term of biosurgery. The crucial technical problem of biosurgery is asepsis of the larvae.

Patients and methods: Since February 1999, we conducted a prospective observational study on the use of maggot debridement therapy in the management of ulcers refractory to standard treatment.

Results: During the first 5 months we observed five bloodstream infections (four with Providencia stuartii and one with Candida albicans) in 24 patients (21%) treated with maggots. The blood isolates could be traced back to contaminated maggots. Accordingly, the disinfecting procedure of the maggots was optimized and the fly species was changed from Protophormia terraenovae to Phaenicia (Lucilia) sericata. With the new procedure, no case of sepsis occurred in 45 patients treated between January 2000 and December 2001 (p < 0.005).

Conclusion: Despite promising benefits, maggot debridement therapy can be threatened by serious infectious complications. With an appropriate disinfecting procedure, maggots free of pathogens can be obtained. Provided the maggots have been effectively disinfected, their application on chronic ulcers seems to be safe.