Do maggots have an influence on bacterial growth? A study on the susceptibility of strains of six different bacterial species to maggots of Lucilia sericata and their excretions/secretions

Abstract

Purpose: The maggots of Lucilia sericata are successfully used as a treatment for infected wounds. Many articles are published about possible direct antibacterial properties of maggots and their excretions/secretions (ES), but with different results. The present study reinvestigates the susceptibility of six bacterial strains to maggots and their ES.

Methods: Live maggots were added to a bacterial suspension. After incubation for 16 h, the bacterial growth in this suspension was compared with the growth in a suspension without maggots. We tested Instar-1 and Instar-3 maggots and compared nutrient broths. A turbidimetric assay investigated the antibacterial activity of ES. Finally, we compared the bacterial growth of Gram-positive and Gram-negative bacteria.

Results: The test with live maggots showed an increase of bacterial growth. Instar-1 maggots stimulated more bacterial growth than Instar-3 maggots, as well as the use of a more nutritious broth. The turbidimetric assay showed no inhibition of bacterial growth. For all bacteria, except Pseudomonas aeruginosa, an increase in bacterial growth was shown.

Conclusion: There is no direct antibacterial effect of maggots and/or ES in vitro, however in clinical observations maggot therapy is successful. More research is needed to focus on possible indirect antibacterial activity, such as an immune-related effect.