Selective Antibiofilm Effects of Lucilia sericata Larvae Secretions/Excretions against Wound Pathogens.

Background. Maggot debridement therapy (MDT), using Lucilia sericata larvae, represents efficient, simple, and low-cost therapy for the treatment of chronic wounds. Aim. The aim was to investigate the antibiofilm activity of maggot excretions/secretions (ES) against biofilm of wound isolates Staphylococcus aureus (S. aureus), Enterobacter cloacae (E. cloacae), and Proteus mirabilis (P. mirabilis). Methods. Quantification of biofilm formation, was carried out using a microtiter plate assay. Proteolytic activity of maggot ES was performed using skim milk agar plates. A solid phase extraction and reverse phase HPLC C18 chromatography were employed to the isolate of maggot ES antibiofilm compounds. Results. Maggot ES at 100 mg/mL concentration significantly reduced biofilm formation thus disrupting established biofilm of E. cloacae. Heat-treated ES did not show any antibiofilm activity towards E. cloacae. Similar results were obtained in the case of S. aureus; however, the heat-treatment of maggot ES did not affect its antibiofilm activity. Moreover, a compound with molecular weight of 25 kDa exhibiting antibiofilm activity was identified in maggot ES. On the other hand, maggot ES protected and even stimulated P. mirabilis biofilm formation. Conclusions. Our results suggest that maggot ES may act selectively against different bacterial strain.