Identification of characteristics of Staphylococcus aureus isolates from Suez Canal University Hospitals in Ismailia, Egypt

Background: Staphylococcus aureus is one of the most common pathogens causing hospital and community-associated infections worldwide. The prevalence of methicillin resistant S. aureus (MRSA) has become a global threat to public health. Only a few agents are available nowadays to treat MRSA infections. Accessory gene regulator dysfunction has been associated with MRSA and multi drug resistance phenotypes. Our study objectives were to Identify phenotypic characteristics and antibiotic susceptibility profile of S. aureus isolates from Suez Canal University hospitals and to study the relation between Agr functionality and resistance to various antibiotics. Methods: S. aureus isolates were collected from different patients admitted to Suez Canal University Hospitals, identified by conventional methods and antibiotic susceptibility was performed using Kirby-Bauer disk diffusion method. Inducible clindamycin test was performed. Agr functionality was determined using colony spreading test. Results: The study included 100 S. aureus isolates obtained from 195 patients, The highest isolation was from ICUs 31% followed by outpatients 24%. MRSA isolates represented 96% of all isolates. The highest antibiotic resistance rate was to cefoxitin (96%) followed by gentamicin (71%) and erythromycin (51%). Twelve isolates (12%) had inducible clindamycin resistance. Agr dysfunction was detected in 36% of all isolates. Most MDR isolates (52.8%) had dysfunctional Agr. Conclusion: A worrisome situation of a rising number of MRSA and MDR S. aureus isolates was detected in SCUHs. Also, we have detected the presence of an increasing number of Agr dysfunctional S. aureus isolates which was associated with multidrug resistance.