Antibiofilm Effect of Melittin on Nosocomial Biofilm Producing Staphylococcus aureus Strains

Staphylococcus aureus is one of important pathogen in burn infections in many hospitals in the world. Today’s, Multi-drug resistant S. aureus are frequently reported and therefore antimicrobial peptides are suggested to treatment of microbial infections. Accordingly, this study was aimed to purification of melittin from Iranian honey bee venom and evaluation of its activity on biofilm positive S. aureus isolated from Shahid Motahari Burns Hospital. 50 samples of S. aureus were collected from the hospital and diagnosed by routine standard.
Melittin purified by Reverse-Phase HPLC technique, lyophilized, and its peptide content was determined by BCA method. Staphylococcus strains were cultured in TSB glucose medium and the biofilm stained with crystal violet and final OD was documented by a spectrophotometer. Increase of OD comparing to glucose free medium indicates biofilm formation. After that MIC and MBC of biofilm positive strains were determined at the dose of MIC. To confirm the lethality of melittin on the bacteria that was grown in biofilm, the surface of microplate was scratched and a sample was cultured on Muller Hinton agar. The results showed that that melittin was able to kill all of the bacteria in biofilm.
20 peaks were seen in chromatogram. The OD average for biofilm production was 2.35 units. The mean OD for the bacteria group that exposed to the dose of one MIC was determined as 1.39.
The majority of S. aureus strains were biofilm producer that this fact could be very important in terms of treatment strategy. Melittin was able to degrade the produced biofilm during two hours and also killed almost all of the examined bacteria. Comparing the efficiency of melittin with other conventional antibiotics showed that study on development of melittin’s applications is of high value.