Background: Pediatric sepsis due to Staphylococcus aureus (S. aureus) is associated with high morbidity and mortality. Accessory-Gene-Regulator (agr) has a role in the pathogenesis of S. aureus through controlling and regulating the expression of virulence genes. Therefore, the aim of the present study was to investigate the prevalence of genotypes of the agr system in S. aureus isolated from children with sepsis and to assess their relationship to biofilm formation and antibiotic resistance. Methods: The study was a retrograde cross-sectional study that included 131 children with health care associated sepsis due to S. aureus. The isolated S. aureus was investigated for their ability to form biofilm by microplate method, antibiotic susceptibility pattern by disc diffusion method, and molecular determination of agr genotypes by polymerase chain reaction (PCR). Results: Methicillin resistant S. aureus (MRSA) was …