Developing of antibiotic resistance is a global issue. Treatment of antibiotic resistance ophthalmic infections is a problem in ophthalmology. Lucilia sericata larvae have been used for non-healing wounds, particularly those infected by the multidrug resistant pathogen (e.g. methicillin resistant Staphylococcus aureus (MRSA)). In this study, we have studied the in vitro activities of larval excreta / secreta (ES) against ocular isolated S. aureus.

In this experimental study, approximately 5 g third-instar larvae were used for the collection of excreta/secreta. After incubation of the larvae, the supernatant was centrifuged to remove particulate material. The crude excreta/secreta were sterilized with 0.22 micrometer filter. Determination of the antibacterial activity of ES on an eye isolated Staphylococcus aureus was performed by in vitro killing test. 100 µl of the ES was transferred to micro tube containing 100 µl of the bacterial culture with 1×10-6 concentration. 100 µl each sample was cultured on the BHI agar plates every hour, over 9 hours. Plates were incubated at 37 °C and after 15 hours the bacterial colonies were counted. For controls, ES was replaced with sterile PBS.

Aqueous extract from of L. sericata larvae showed antibacterial activity against S. aureus. The results revealed that ES reduced the number of S. aureus bacteria after 3 hours by 75%, relative to control.

From this investigation, it was concluded that antimicrobial activity of L. sericata larvae extracts against methicillin-resistant S. aureus shows the medicinal value and this extract is very effective in treating eye infections caused by S. aureus. Additional studies are required to separate bioactive component in ES extract.