Dual-site sampling improved detection rates for MRSA colonization in patients with cutaneous abscesses

Area of Science:

• Infectious Diseases
• Microbiology
• Clinical Diagnostics

Background:

• Extranasal sites are recognized reservoirs for Staphylococcus aureus colonization.
• Methicillin-resistant S. aureus (MRSA) screening and infection control are critical public health concerns.
• The efficacy of extranasal screening, specifically inguinal sites, for MRSA requires further investigation.

Purpose of the Study:

• To evaluate the utility of the Xpert SA Nasal Complete assay for MRSA detection in inguinal specimens.
• To compare MRSA colonization rates between inguinal and nares (nose) specimens.
• To assess the diagnostic performance of the Xpert assay against broth enrichment culture.

Main Methods:

• Adults presenting with cutaneous abscesses were enrolled (n=162).
• Nasal and inguinal specimens were collected for MRSA screening.
• Specimens were analyzed using the Xpert SA Nasal Complete assay (PCR) and broth enrichment culture.
• Results were compared between specimen types and methods.

Main Results:

• Inguinal specimens showed higher MRSA positivity rates (24-26%) compared to nares specimens (19%).
• Nasal screening alone would miss approximately 6% of MRSA-colonized individuals.
• The Xpert SA Nasal Complete assay demonstrated high sensitivity (89%) and specificity (97%) compared to culture.

Conclusions:

• Inguinal sites represent a more prevalent reservoir for MRSA than nares in patients with cutaneous abscesses.
• Incorporating inguinal screening can enhance MRSA detection and potentially improve infection control measures.
• The Xpert SA Nasal Complete assay is a reliable tool for MRSA detection in both nasal and inguinal specimens.