A Study of Accessory Gene Regulator, Biofilm Formation, and Antibiotics Resistance of Staphylococcus aureus Isolated from Pediatric Patients with Healthcare-Associated Sepsis

Abstract

Background: Among pediatric patients, Staphylococcus aureus (S. aureus) is a significant bacterium that causes healthcare-associated sepsis. Antibiotic resistance and biofilm development, a virulence factor in S. aureus, pose significant challenges to infection control. The accessory gene regulator (agr) is a regulatory gene believed to control multiple factors of virulence in Staphylococcus aureus. Objective: To investigate the ability of isolated S. aureus from pediatric patients with sepsis to produce biofilms and explore different types of agr systems and their interrelationships. Methodology: In this work, 115staph. aureus strains isolated from positive blood cultures from pediatric patients diagnosed with sepsis were tested for biofilm production, resistance to antibiotics and different types of agr genes by PCR. Results: Out of 115 of S. aureus strains, 91.3% of the isolates were capable of forming biofilm. We observed a significant biofilm formation capacity in 52 strains (49.5%), a moderate capacity in 31 strains (29.5%), and a weak capacity in (20.9%). PCR revealed that the agrI and agrIII genes were the most prevalent, with prevalence rates of 41.7% and 25.2 respectively, while the agrII gene was the least common at 9.6%, respectively. Also we reported a strong link between the placement of peripheral catheters and genotype Agr II. Also we reported a strong link between genotype agr II and the growth of robust biofilm. Conclusion: S. aureus forms a strong biofilm in pediatric patients with healthcare-associated sepsis which indicates virulence and difficulty in its eradication by antibiotics therapy. Agr II showed a positive association with the formation of strong biofilms.