A Survey of presence of accessory gene regulator (agr) in sensitive and methicillin-resistant (mecA) Staphylococcus aureus in clinical samples of Bojnurd, Northeastern Iran

Staphylococcus aureus is one of the most important pathogens in humans. The development of resistance to various antibiotics in this bacterium has become a global problem that due to the importance accessory gene regulator (agr) in this bacterium, which is responsible for coordinating and controlling the production and secretion of toxins and virulence factors. The purpose of this study was to investigate the pattern of antibiotic resistance and determine specific groups agr in order to find the dominant type of region in sensitive and methicillin-resistant Staphylococcus aureus.

Different clinical samples were prepared of Clients to Imam Reza Hospital in Bojnourd and phenotypic tests were performed on Staphylococcus aureus strains. Disc diffusion method was used to confirm drug sensitivity. DNA extraction was performed using a QiaAmp kit and Methicillin-resistant strains with mecA gene were identified by polymerase chain reaction (PCR) and agr groups were determined by multiplex PCR.

In this study, the highest antibiotic resistance of Staphylococcus aureus against cefoxitin was (75%). Isolates (73. %) have mecA gene and in sensitive and methicillin resistant strains the highest percentage belongs to agrI group with frequency of 60.71% and 15.58%.

Due to the fact that the pathogenicity of strains belonging to agr groups is different in various regions, it is necessary to determine the strains isolated from each region in order to find the dominant type in that region.