Effect of Bioactive Peptide, KR-12-a5, on Growth of Clinical Methicillin-resistant Staphylococcus aureus Isolates

Abstract

Staphylococcus aureus is one of the most frequent infectious agents causing hospitals and community associated infections. Developing the treatment for methicillin resistant S. aureus (MRSA) is a challenging arena for effective therapeutics. Application of antimicrobial peptides is an alternative option to control MRSA infection. The potential of the bioactive peptide against MRSA was previously revealed; however, the study on the effect of KR-12-a5 on the various clinical MRSA growth was not elucidated. This study aimed to investigate the effect of bioactive peptide KR-12-a5 on the growth of MRSA isolated from patients. Evaluation of KR-12-a5 peptide using antimicrobial susceptibility test was performed. Antimicrobial activity assay showed that the KR-12-a5 at 2-64 μM could inhibit the growth of S. aureus ATCC 29213 in the range of 55.0±0.8%-81.0±6.2%. In case of KR-12-a5 treatment at 2, 4, and 8 μM, growth of all twenty clinical MRSA isolates could be inhibited less than 90% in the range of 0.0-75.9±1.6%, 0.0-73.0±4.2%, and 0.0-77.1±1.7%, respectively. Whereas the treatment of those at 16, 32, and 64 μM, growth of clinical MRSA could be significantly inhibited more than 90% (p < 0.05) in the range of 94.3±6.7%-100.4±0.4% in 3 isolates (15%), 97.3±0.3%-99.5±0.2% in 4 isolates (20%), and 91.6±0.8%-99.0±0.1% in 9 isolates (45%), respectively. These findings indicated that the KR-12-a5 effectively controls growth of both S. aureus ATCC 29213 and clinical MRSA isolates