Comparative Evaluation of the Sensitivity and Specificity of Three Culture Media for the Detection of Staphylococcus Aureus

Staphylococcus aureus remains a major cause of community- and hospital-acquired infections, requiring accurate and timely laboratory detection. Culture-based methods continue to represent the foundation of routine diagnosis; however, the diagnostic performance of different culture media varies depending on their selectivity and interpretability. Objective: Our study aimed to comparatively evaluate the sensitivity and specificity of blood agar, Mannitol Salt Agar (MSA), and CHROMagar Staphylococcus for the detection of Staphylococcus aureus from clinical specimens under standardized laboratory conditions. Methods: A total of 105 clinical specimens were inoculated in parallel onto the three culture media and incubated under uniform conditions. Presumptive positive cultures were identified based on medium-specific morphological characteristics and subsequently subjected to confirmatory phenotypic identification, which served as the reference standard. Diagnostic accuracy parameters, including sensitivity, specificity, positive predictive value, and negative predictive value, were calculated using standard 2×2 contingency tables. Results: Blood agar demonstrated maximal sensitivity but lower specificity due to the growth of morphologically similar organisms. MSA showed high specificity with reduced sensitivity at early incubation times, improving after prolonged incubation. CHROMagar Staphylococcus achieved both high sensitivity and specificity, facilitating rapid and reliable presumptive identification. Conclusions: Chromogenic media represent an effective option for optimizing diagnostic accuracy and workflow efficiency in routine Staphylococcus aureus detection.