Isolation and diagnosis of staphylococcus aureus and detection of some virulence genes using pcr technique depending on the specific primers

Staphylococcus aureus has spread around the globe and is now a major public health problem as one of the most prevalent causes of nosocomial infections. The aim of this study was to determine the virulence genes of S. aureus. From November 2021 until March 2022, the study was conducted in the medical microbiology laboratories at Al-Ramadi Teaching Hospital and Haditha Hospital. The 110 samples were detected utilizing microbiological and biochemical testing from blood cultures, wound infections, urine cultures, burns swabs, vaginal and ear infections. Six different antibiotics were tested for sensitivity (Tetracycline, Cephalexin, Erythromycin, Clindamycin, Chloramphenicol, Trimethoprim). The isolates were then subjected to molecular screening for virulence genes. S. aureus was found in 110 isolates (52.38%). The results showed high resistance to Tetracycline (72.30%), Erythromycin (61.55%), Cephalexin (46.15%), Clindamycin (36.92%), Chloramphenicol (33.84%) and Trimethoprim (20%). This study recorded the highest sensitivity in the antibiotics Trimethoprim, Chloramphenicol and Clindamycin (80%), (66.15%), (64.61%), respectively. 16srRNA, hla, etb, crtN genes were detected in 110 (100%), 96 (87.5%), 55 (50%), 96 (87.5%) of the isolates, respectively. S. aueus which contains toxin genes, is seen in large numbers among clinical isolates. The results of the sequence analysis was analyzed by blast in the National Center Biotechnology Information (NCBI) and BioEdit program to detect polymorphism, the sequence by (NCBI) found 4 variations between 3 transversions , 1 transitions nucleotide, showed 99% under sequence ID: MG230264.1| and ID: MH603394.1 from 9 -788, 75-984 number of nucleotide from S. aureus strain AM and Staphylococcus aureus strain AT1 respectively of Gene Bank, and score (1394) and (1637).