Prevalence of Multidrug Resistant Staphylococcus aureus and their Pathogenic Toxins Genes in Iraqi Patients, 2022-2023

 Methicillin Resistance Staphylococcus aureus (MRSA) causes staph infections, produces numerous toxins and virulence factors, and displays antibiotic resistance. Therefore, this study aimed to detect MRSA and its antibiotic-resistant patterns and evaluate the toxins genes in S. aureus isolates from Baghdad, Iraq.

 Two hundred twenty bacterial samples were collected from different clinical sources in Iraq, 2022-2023. The diagnosis was made using traditional culture, microscopic examinations, and molecular diagnosis using the 16srRNA gene and mecA gene used for Methicillin Resistance detection. In addition, Antibiotic resistance patterns were detected using VITEK-2. Also, the toxins genes were determined by sequencing.

 Fifty isolates were identified as S. aureus, and the strains showed high resistance to Benzylpenicillin, Erythromycin, Oxacillin, and Clindamycin. PCR showed a prevalence of the mecA gene in methicillin resistance S. aureus isolates by 100%, while toxin genes that were present in S. aureus were LukD/E gene 50(100%), eta gene 50(100%), etd gene 47(94%), LukS/F gene 34(68%) and tst gene 21(42%). All isolates tested negative for the etb gene. The results of the sequencing analysis of the studied genes showed that there were no genetic mutations. They were 100% identical except for the eta gene, and the results indicated three genetic mutations.

 All S. aureus isolates had the mecA gene for methicillin resistance, and S. aureus possessed toxin genes. The sequencing analysis of the eta gene indicated the presence of various mutations, including the silent mutations.