Molecular study of staphylococcus aureus based on PCR restriction fragment length polymorphism and DNA sequence analysis of the one of virulence factor gene

The current study involved collecting 100 of 165 clinical samples in the city of Ramadi to investigate the presence of S.aureus bacteria. According to the isolation source, 45 samples were taken from the skin, 32 from the wound, 17 from the blood and 6 from the urine. The results show that the highest percentage of S.aureus in skin samples is 45%. In the study, susceptibility tests were performed against selected bacterial isolates and selected pathological isolates for 12 types of antibiotics, namely Amikacin, Amoxicillin, Ampicillin, Erythromycin, Gentamicin, Clindamycin, Chloramphenicol, Penicillin, Cefoxitin, Ciprofloxacin, Trimethoprim and Vancomycin. Test results show that it is highly resistant to all three types of these antibiotics, with 99% for Penicillin, 91% for Ampicillin and 85% for Trimethoprim. Although the resistance of the isolates differed for other antibiotics in the study, it was observed that they were 99% sensitive to Vancomycin and 79% to Chloramphenicol. In the study, genomic DNA was also extracted from selected bacterial isolates mecA and pvl in order to examine the genetic sequence of the isolates. It turned out that the MecA gene was present in 64 of 100 samples analyzed, corresponding to 64% proportionally. While the Restriction Fragment Length Polymorphism (RFLP) approach is used to confirm the diversity of the genetic content of the PCR domains, the amplification of the coa and spa genes, the presence of the coa gene and the spa gene were investigated in S. aureus strains that separated these genes using specific primers. It was aimed to see the 575 bp band for both genes. As a result, it was determined that each of them has two amplification patterns and the genes have different PCR product sizes. While 405, 810 and 891 bp values were observed for the Coa gene, respectively, 240, 1200 and 1296 bp values were observed for the Spa gene. 2022, 66 pages Keywords: Staphylococcus aureus, Antibiotic tesistance, Virulence factors, Ramadi, Iraq