Mahtab Alsadat Madani borujeni - Department of pathobiology, Shahrekord University, Shahrekord, Iran
Mohammadreza Mahzounieh - Department of pathobiology, Shahrekord University, Shahrekord, Iran
Azizallah Ebrahimi - Department of pathobiology, Shahrekord University, Shahrekord, Iran

Introduction and objective: Staphylococcus aureus (S. aureus) is considered one of the most important pathogens, responsible for nosocomial infections. Many clinical isolates are resistant to common anti-bacterial drugs. The widespread resistance to antibiotics push microbiologists to seek alternative therapeutic methods to replace with ordinary methods for preventing and therapy of bacterial infection. So, phage therapy and their potential in killing of bacteria at the end of infectious cycle are becoming more interesting. Phage therapy could be used as a chemotherapy alternative method. The aim of this study was to isolate and identify phages which had lytic effect on MRSA bacteria. Materials and Methods: S. aureus were isolated from blood, sputum, urine, ear, eyes, nose, abscess, pleural fluid, peritoneal fluid, Broncho Alveolar Lavage, trachea, throat, wound secretions samples, and hospital environment of two education hospitals in Isfahan and Shiraz, Iran. The resistance to methicillin was measured and determined by disk diffusion method and mecA gene, was detected by PCR method. Staphylophages were isolated from Isfahan urban sewage samples. Double Layer Agar method, was used to detection of lytic phages and the developing of plaque, was considered the sign of destructive phage against S. aureus. The identification of phages was carried out based on morphology characteristics by TEM images. Results: Out of 133 samples, 92.4% S. aureus isolates were Methicillin resistant which 88.7% of them carried mecA gene. Fifty-eight samples were lysed by isolated phage cocktails and produced plaques. They were belonged to families: Siphoviridae, myoviridae, Tecticoviridae, Corticoviridae, and Microviridae. Conclusion: Different bacteriophages in four phage cocktails had good lytic effects on S. aureus clinical isolates. As using of phage cocktails may have potential to be an alternative chemotherapy specially against antibiotic resistant pathogenic isolates, it is necessary to study lytic effects in animal models.

Bacteriophages, Phage therapy, Staphylococcus aureus, MRSA, mecA