In chronic
wounds, it may be clinically important to remove extracellular bacterial and patient
DNA as its presence may impede wound healing and promote bacterial survival in biofilm, in which extracellular
DNA forms part of the biofilm architecture. As medicinal maggots, larvae of Lucilia sericata Meigen (Diptera: Calliphoridae) have been shown to efficiently debride
wounds it became of interest to investigate their excretions/secretions (ES) for the presence of
a deoxyribonuclease (
DNAse) activity. Excretions/secretions products were shown to contain a
DNAse, with
magnesium,
sodium and
calcium metal ion dependency, and a native molecular mass following affinity purification of approximately 45 kDa. The affinity purified
DNAse degraded genomic
bacterial DNA per se,
DNA from the slough/eschar of a venous
leg ulcer, and extracellular
bacterial DNA in biofilms pre-formed from a clinical isolate of Pseudomonas aeruginosa. The latter finding highlights an important attribute of the
DNAse, given the frequency of P. aeruginosa
infection in non-healing
wounds and the fact that P. aeruginosa
virulence factors can be toxic to maggots. Maggot
DNAse is thus a competent
enzyme derived from a rational source, with the potential to assist in clinical
wound debridement by removing extracellular
DNA from tissue and biofilm, and promoting tissue viability, while liberating proteinaceous slough/eschar for
debridement by the suite of
proteinases secreted by L. sericata.