Quantification of Myxovirus Resistance Protein A (MxA) in Nasopharyngeal Swabs to Differentiate Viral from Bacterial Acute Respiratory Infections in Pediatric Cohorts
Research Paper | 2026 | Volume 1 | Issue 01 | Page 52-56
Dr. Srinathan Ramayea, Assistant Professor Department of Respiratory Medicine, Under Dr. MGR Medical University, TN
ABSTRACT
BACKGROUND: Distinguishing between viral and bacterial acute respiratory infections (ARIs) in pediatric populations remains a significant clinical challenge. Over-reliance on antibiotics for viral illnesses contributes to global antimicrobial resistance. Myxovirus Resistance Protein A (MxA) is an interferon-induced intracellular protein that is highly expressed in response to viral infection, offering a potential biomarker for rapid diagnostic triage.
METHODS: This prospective diagnostic accuracy study enrolled 200 children (aged 6 months to 12 years) presenting with acute respiratory symptoms. Nasopharyngeal swabs were collected at the time of presentation. Viral infections were confirmed via multiplex real-time PCR, and bacterial infections were identified through bacterial culture and/or clinical diagnostic algorithms. MxA protein levels in nasopharyngeal epithelial cells were quantified using an enzyme-linked immunosorbent assay (ELISA) and localized via immunofluorescence. The diagnostic utility of MxA was evaluated against clinical standard-of-care, with receiver operating characteristic (ROC) curves used to determine optimal diagnostic cut-offs for viral infection.
RESULTS: MxA expression levels were significantly higher in patients with confirmed viral infections (median 450 pg/mL) compared to those with bacterial infections (median 45 pg/mL, p < 0.001) or healthy controls (median 18 pg/mL, p < 0.0001). MxA quantification demonstrated high diagnostic accuracy, with an area under the ROC curve (AUC) of 0.92 (95% CI: 0.88–0.96). At the optimized cut-off of 120 pg/mL, the sensitivity and specificity for differentiating viral from bacterial ARIs were 88% and 86%, respectively. Furthermore, MxA levels were independent of the specific viral pathogen, suggesting it acts as a universal sentinel marker for interferon-driven viral immune responses.
CONCLUSION: Nasopharyngeal MxA quantification serves as a highly sensitive and specific biomarker for differentiating viral from bacterial respiratory infections in pediatric cohorts. Implementation of this rapid diagnostic assay has the potential to significantly reduce unnecessary antibiotic prescribing in pediatric primary and urgent care settings.
KEYWORDS: MxA Protein, Pediatric Respiratory Infection, Viral vs. Bacterial, Biomarker, Antimicrobial Stewardship, Point-of-Care Diagnostics.
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