Antimicrobial Resistance Patterns of Staphylococcus aureus in a Pediatric Population: A Cross-Sectional Analysis of Demographic, Clinical, and Laboratory Correlates in Qom, Iran (2019–2020)

Background: Staphylococcus aureu resistance poses a critical threat to pediatric care. We aimed to comprehensively evaluate S. aureus resistance patterns and their associations with demographic (age, sex, ethnicity), clinical (disease severity, sampling site), and laboratory parameters (WBC, CRP) in a pediatric referral center in Qom, Iran. Methods: A retrospective cross-sectional study (Mar 2019–Mar 2020) used medical records of patients under 15. Clinical samples were cultured on blood and mannitol salt agar; S. aureus was identified via catalase/coagulase tests. Antibiotic resistance was assessed by disk diffusion. Of 24,342 specimens from hospitalized and outpatient children, 216 tested positive for S. aureus. Results: Among 216 isolates (120 males, 96 females; 167 Iranian, 37 Afghan, 12 Iraqi), 92 were from inpatients and 124 from outpatients. High resistance was seen to ampicillin (77.3%), erythromycin (65%), and cefixime (62.5%). Resistance to meropenem (43%) and vancomycin (12%; including 8.3% MRSA) was concerning. Multidrug resistance (≥3 classes) appeared in 22.7%. Lowest resistance was to imipenem (0%), co-amoxiclav (3%), and amikacin (6%). Complete resistance to cefepime, nalidixic acid, and nitrofurantoin was seen in a few samples (n≤10), possibly due to sampling bias. Conclusion: The study reveals emerging resistance to newer antibiotics, including vancomycin and meropenem, highlighting the need for region-specific stewardship and better surveillance to combat antimicrobial-resistant S. aureus in pediatric populations.