Anti-biofilm Activity of Melittin against Acinetbacter baumannii Strains Isolated from Patients Suffered from Burn Infection

Acinetobacter baumannii is a dangerous agent responsible for burn infection. Currently, antibiotic resistance is being increased and in these conditions, antimicrobial peptides have suggested to overcome this kind of infections. Accordingly, this study was aimed to evaluation of melittin peptide on degradation of biofilm produced by A. baumannii and killing effect of this peptide on bacteria in depth of biofilm.
Melittin was purified from bee venom by Reverse-Phase HPLC. Biofilm producing ability of strains was evaluated by spectrophotometry. Then, degradation and killing effect of melittin on biofilm and bacteria were examined by spectrophotometry and culture method respectively.
The results indicated that all strains have biofilm, production ability and the average of OD was estimated at 0.98. This average was dropped to 0.15 OD due to degradation of biofilm. The culture results showed that all bacteria were killed in different amounts of melittin.
The amount of biofilm production was varied among the bacteria. This issue pointed out to this fact that gene expression of biofilm related genes is different subsequently. Degradation of biofilm by melittin would be induced by pore formation in the surface of biofilm and this issue is boosted by increasing in peptide amount too. Killing ability of melittin on bacteria demonstrate that melittin can be able to penetrate across the biofilm and invade to bacteria.