Behnaz Rahmani - Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Akram Astani - Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Hossein Zarei Jaliani - Department of Medical Biotechnology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mohammad Hassan Kheirandish - Department of Medical Biotechnology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Ahmad Mosadegh - Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

Objective(s): Staphylococcus aureus has become a major clinical concern due to the growing prevalence of multi-drug resistant (MDR) strains. Enzybioticts are peptidoglycan hydrolases that are recently introduced as an alternative agent to confront the MDR strains with a more effective mechanism than conventional antibiotics.  In this regard, our study aimed to evaluate the kinetic stability of LasA protease as a potent enzybiotic in the specific destruction of the S. aureus cell wall. Materials and Methods: The catalytic domain of the Codon-optimized LasA gene was sub-cloned into pET۲۸a vector, and BL۲۱ DE۳ cells were used for protein expression. Recombinant LasA protein was affinity purified by Ni-NTA column and staphylolytic activity of the LasA protein against methicillin-resistant strains was evaluated by disk diffusion and MIC test. The kinetic stability was evaluated in different temperatures during ۴۸ hr. Results: Our results revealed that LasA protein can completely prevent the growth of Methicillin-resistant S. aureus (MRSA) strain and inhibit the examined strain at the amount of ۴ µg. furthermore, the catalytic domain of LasA protein can tolerate higher temperatures as well. Conclusion: With regard to the failure of conventional antibiotics in treatment of MRSA infections, novel agents to combat multidrug-resistant strains are needed. The present study shows that LasA protein can eradicate MRSA strains, so it can be promising for the treatment of antibiotic-resistant staphylococci infection. The kinetic stability of LasA has also confirmed the possibility of industrial-scale manufacturing for the subsequent use of the enzyme clinically.

Antibiotic, LasA protease, MRSA, Stability, Staphylolysin