Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 12 1 2024 02 06 43 58 Sara Rashid Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Khorasan Razavi, Iran Madjid Momeni-Moghaddam Hakim Sabzevari University Zahra Ghavidel Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Khorasan Razavi, Iran 2023 12 27 2024 02 05 Background:   This study explores the impact of Lucilia sericata maggots on the development and eradication of biofilms created by the pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. Methods:   We assessed the influence of Lucilia sericata maggot extract on the viability of planktonic bacteria, the formation and disruption of biofilms, bacterial metabolic activity. Also the effect of simultaneous ES-antibiotic treatment in biofilm elimination was investigated. Additionally, the expression levels of genes associated with biofilm formation, namely LasI, psLA, agrA, and icaD was studied. Results:   The results showed that ES can reduce the viability of planktonic S. aureus, significantly. Furthermore, ES of larvae fed on S. aureus-infected meat displayed the most substantial inhibition of biofilm formation (62.11% and 75.04% inhibition for S. aureus and P. aeruginosa, respectively). A similar trend was observed in biofilm destruction, with values of 56.67% and 68.50% inhibition for S. aureus and P. aeruginosa, respectively. The simultaneous application of ES of larvae that fed on S. aureus-infected meat and the minimum inhibitory concentration (MIC) of gentamicin resulted in 100% inhibition of biofilm formation by S. aureus. Notably, the group treated with ES of larvae fed on S. aureus-infected meat exhibited the most significant reduction in metabolic activity, with values of 95.03% and 68.25% for S. aureus and P. aeruginosa, respectively. The expression of LAsI and pslA genes in P. aeruginosa and the expression of agrA and icaD genes in S. aureus has decreased Conclusion:   The findings of this study demonstrate that maggot extract has not only impacted the formation, but also eliminated the biofilms of S. aureus and P. aeruginosa. https://jmb.tums.ac.ir/index.php/jmb/article/view/506