title: The antibacterial activity against MRSA strains and other bacteria of a <500Da fraction from maggot excretions/secretions of Lucilia sericata (Diptera: Calliphoridae).
abstract: The application of Lucilia sericata larvae to chronic, infected wounds results in the rapid elimination of infecting microorganisms, including MRSA. Previously, we demonstrated in vitro antibacterial activity of native excretions/secretions (nES) from L. sericata and partially purified two low mass antibacterial compounds with masses of 0.5-10kDa and <500Da. The present study reports the antibacterial effects of the <500Da fraction (ES<500) on the growth and morphology of a range of bacteria, including 12 MRSA strains. Distinct morphological changes were observed in Bacillus cereus and Escherichia coli following exposure to ES<500. Flow cytometry and confocal microscopy analyses, in conjunction with turbidometric and CFU assays, revealed bacteriostatic activity of nES against S. aureus and E. coli. ES<500 also demonstrated bacteriostatic activity against S. aureus, however, bactericidal activity and the induction of a viable but non-culturable state were observed with ES<500-treated E. coli.
authors.affiliation: Department of Biological Sciences, SOTEAS, Swansea University, Singleton Park, Swansea, SA2 8PP, UK. a.bexfield@swansea.ac.uk
authors.forename: Alyson
authors.initials: A
authors.lastname: Bexfield
authors.forename: A Elizabeth
authors.initials: AE
authors.lastname: Bond
authors.forename: Emily C
authors.initials: EC
authors.lastname: Roberts
authors.forename: Edward
authors.initials: E
authors.lastname: Dudley
authors.forename: Yamni
authors.initials: Y
authors.lastname: Nigam
authors.forename: Stephen
authors.initials: S
authors.lastname: Thomas
authors.forename: Russell P
authors.initials: RP
authors.lastname: Newton
authors.forename: Norman A
authors.initials: NA
authors.lastname: Ratcliffe
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D002457:Cell Extracts / Q000737:chemistry*; D015169:Colony Count, Microbial; D004175:Diptera / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D007814:Larva / Q000737:chemistry; D050296:Microbial Viability; D008970:Molecular Weight
chemical_list: D000900:Anti-Bacterial Agents; D002457:Cell Extracts