Antimicrobial and Antibiofilm Effects of GF-17 Peptide Against Methicillin-Resistant Staphylococcus aureusIsolated from Different Clinical Samples

Abstract

Background: A major human pathogen that causes a variety of diseases is the gram-positive bacteria Staphylococcus aureus. Biofilm production increases its virulence and leads to antimicrobial resistance, especially in methicillin-resistant S. aureus (MRSA) strains. Antimicrobial peptides, including GF-17, have shown promise in the fight against S. aureus that is resistant to many drugs. Methods: Using biochemical tests, selective media, VITEK2-compact system, and molecular confirmation, 190 clinical samples were gathered from hospitals in Baghdad and screened for Methicillin-resistant S. aureus (MRSA). Twelve antibiotics were used in the disk diffusion method to assess antibiotic susceptibility. A microdilution technique was used to determine GF-17's minimum inhibitory concentration (MIC). GF-17's anti-biofilm activity was assessed with an ELISA reader and crystal violet staining. Furthermore, RT-qPCR was used to assess the expression of biofilm-associated genes (icaA and rbf). The purpose of this study is to assess how well GF-17 inhibits Methicillin-resistant S. aureus isolates that were taken from clinical samples. Results: Of the isolates, 44 were identified as MRSA and exhibited high levels of resistance to Vancomycin (61.3%) and Methicillin (100%). Strong antibacterial action was demonstrated by GF-17, with MIC values ranging from 7.8 to 15.6 µg/ml. Our results showed a clear effect on their ability to form biofilms, as the isolates became weak in forming biofilms, after having been strong before treatment with the antimicrobial peptide GF-17. In treated isolates, biofilm formation was considerably decreased, and RT-qPCR analysis showed that icaA expression was markedly downregulated but rbf expression was unaffected. Conclusion: When it came to Methicillin-resistant S. aureus (MRSA), GF-17 showed notable inhibitory and anti-biofilm efficacy. These results imply that it may be used as a therapeutic substitute to treat MRSA infections. Its clinical uses and mechanisms of action need to be investigated further.