Synergistic activity of melittin with mupirocin: A study against methicillin-resistant S. Aureus (MRSA) and methicillin-susceptible S. Aureus (MSSA) isolates

Abstract

Methicillin-Resistant Staphylococcus aureus (MRSA) biofilms are involved in various nosocomial infections, being in the limelight of academic research. The current study aimed to determine the antimicrobial effects of melittin on planktonic and biofilm forms of S. aureus . Following the identification of MRSA and SCCmec types (using PCR method), Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and fractional inhibitory concentration index (FICi), for melittin and mupirocin were determined by broth microdilution assay. Melittin anti-biofilm activity was determined, using a microtiter-plate test (MtP) and scanning electron microscope (SEM) methods. The quorum sensing inhibitory activity of ½ MIC melittin was examined using a quantitative real-time RT-PCR method, and melittin cytotoxicity on Vero cells was examined by tetrazolium-based colorimetric (MTT) test. The Results of our study showed that Geometric means of MIC values of the melittin and mupirocin were 4.4 and 14.22 μg/ml respectively. The geometric mean of the FICi for both melittin-mupirocin was 0.75. No S. aureus biofilm was formed and hld gene (as a biofilm regulator) expression down-regulated. It seems that melittin can be useful in the treatment of S. aureus infections (especially MRSA) by reducing the hld expression. Furthermore, synergistic growth-inhibitory effects of mupirocin with melittin could be considered as a promising approach in the treatment of MRSA isolates.

Discovery of Melittin as Triple-Action Agent: Broad-Spectrum Antibacterial, Anti-Biofilm, and Potential Anti-Quorum Sensing Activities

“…The results showed melittin had antibacterial activities against these tested strains, particularly, melittin showed high activity against S. aureus and A. baumannii (Table 1). It is worth noting that melittin has antibacterial activity against Gram-positive and Gram-negative bacteria, which again proves that melittin has a broad spectrum of antibacterial effects as previously reported [33,34]. E. coli, S. aureus, P. aeruginosa, and A. baumannii are particularly important in human and veterinary medicine due to their pathogenicity, virulence, distribution, diversity of clinical signs, and problems related to public health.…”

Trans-Cinnamaldehyde Exhibits Synergy with Conventional Antibiotic against Methicillin-Resistant Staphylococcus aureus

“…We speculated that was because TCA can destroy the biofilm and cell membrane of MRSA. The results of the biofilm inhibition assay indicated that TCA can significantly inhibit the biofilm formation and the expression of the biofilm regulatory gene hld [ 14 ]. The biofilm of MRSA has serious clinical implications, making it difficult to eradicate and more tolerant to antibiotic therapy [ 15 ].…”

Designing Alginate/Chitosan Nanoparticles Containing Echinacea angustifolia: A Novel Candidate for Combating Multidrug‐Resistant Staphylococcus aureus

“…Then, 200 μL of crystal violet (1 % concentration) was added to each well. OD570 was assessed using an ELISA Reader Stat Fax2100 (Awareness Technology, Ukraine) following the addition of 200 μL of acetic acid (33 %) [47] . The results of the biofilm formation were categorized into the following groups:…”