Procedures for determining the antimicrobial activity of maggot excretions and secretions of the green bottle fly: a narrative literature review

The therapeutic benefits obtained from the presence of larvae of certain flies in infected wounds have been mentioned since ancient times. Currently, the so-called maggot therapy or biosurgery is considered a simple, safe, relatively low-cost, and highly effective alternative for treating a wide variety of infected, necrotic, and difficult-to-heal wounds, including those caused by multidrug-resistant bacteria. In addition to the debridement of necrotic wound tissue promoted by larvae, especially from the green bottle fly (Lucilia sericata; Diptera: Calliphoridae), there is much evidence that their native excretions and secretions (NES) contain components with varied antimicrobial activity against Gram-positive and Gram-negative bacteria and activity against fungi. Furthermore, studies have shown the antibiofilm effect of NES. Biofilms represent an additional problem for wound healing because they prevent the action of antibiotics on the pathogens infecting the wound. The antimicrobial effects of crude NES or its molecular components described in studies sometimes present contrasting results when compared. This is probably due to the laboratory methodological aspects used, which range from the preparation of larvae and extraction of NES to the tests used to evaluate their antimicrobial activity. This review aimed to bring together a diversity of laboratory procedures and results that have been described for the antimicrobial potency of NES. Moreover, it aimed to contribute to a greater standardization of the methodologies adopted in new studies to generate more consensual and comparable results.