Molecular detection of toxin genes among staphylococcus aureus isolated from clinical samples

Staphylococcus aureus is widely recognised as a primary nosocomial pathogen due to its extracellular protein toxins and important antimicrobial resistance agents. This study was conducted in several hospitals in Karbala, Iraq, and a total of 240 samples from different clinical sites (urine, burns, wounds, throat swabs, pus, and skin infections) were analysed. All samples were cultured at 37°C using blood agar, chromo agar and mannitol saline agar and subjected to 24 hours aerobic incubation. All samples were then analysed and identified. The youngest individual included in the study was 2 years old and the oldest individual was 74 years old. The highest frequency of S. aureus positive cultures was found in the age group of 20 years with 11 (24.24%) and the lowest frequency was found in the age group of 41-50 years with 3 (4.54%). In the study, S. aureus was detected at higher rates in women (137, 57.1%) than in men (103, 42.9%). S. aureus was detected in 33 of 94 positive cultures (34.7%) in women and 33 of 76 positive cultures (43.4%) in men. The highest rate for S. aureus was observed in cases of skin injury. The eta and mecA genes were positive in 55 isolates (83.33%) and the etb gene was positive in 9 isolates (13.64%). The highest antibiotic resistance of S. aureus isolates was penicillin G (88.24%) and the lowest was vancomycin (11.76%). According to the relationship between genes and antibiotic resistance patterns, no relationship was found between the frequency of etb gene and antibiotic resistance except for eta gene containing clotrimoxazole (p-value=0.039) and mecA gene containing ceftriaxone (p-value=0.001). In conclusion, the prevalence of Staphylococcus aureus isolates, and high rates of antibiotic resistance were found in hospitalised patients.