Combinations of maggot excretions/secretions and antibiotics are effective against Staphylococcus aureus biofilms and the bacteria derived therefrom.
OBJECTIVE
Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. Previously we reported that maggot excretions/secretions (ES) break down Staphylococcus aureus biofilms but do not kill the bacteria. As many antibiotics are not effective against biofilms we assessed the effect of combinations of ES and antibiotics on S. aureus biofilms and on the survival of the bacteria released from the biofilms.


METHODS
Effects of ES, antibiotics (vancomycin, daptomycin or clindamycin) and combinations thereof on S. aureus ATCC 29 213 biofilms and bacterial viability were determined using microtitre plates and in vitro killing assays.


RESULTS
Vancomycin and daptomycin dose-dependently enhanced biofilm formation, whereas clindamycin reduced S. aureus biofilm size. Adding ES to antibiotic incubations caused a complete biofilm breakdown. After a lag time the bacteria derived from biofilms became susceptible to vancomycin and clindamycin, provided that the medium was refreshed. Daptomycin dose-dependently eliminated the biofilm-derived bacteria immediately. Furthermore, it was significantly more effective against bacteria derived from ES-exposed biofilms than those from control biofilms. ES did not affect the activity of the antibiotics against log-phase S. aureus.


CONCLUSIONS
Combinations of maggot ES and antibiotics eliminate S. aureus biofilms and the bacteria derived therefrom.
van der Plas
Mariena J A
MJ
Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
Dambrot
Cheryl
C
Dogterom-Ballering
Heleen C M
HC
Kruithof
Simone
S
van Dissel
Jaap T
JT
Nibbering
Peter H
PH
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D001688:Biological Products / Q000302:isolation & purification / Q000494:pharmacology*; D002981:Clindamycin / Q000494:pharmacology; D017576:Daptomycin / Q000494:pharmacology; D004175:Diptera / Q000737:chemistry*; D004357:Drug Synergism; D006801:Humans; D007814:Larva / Q000737:chemistry; D050296:Microbial Viability / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology*; D014640:Vancomycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001688:Biological Products; D002981:Clindamycin; D014640:Vancomycin; D017576:Daptomycin