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Updated: Jun 15, 2025
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Persistent methicillin-resistant Staphylococcus aureus (MRSA) nares test positivity during initial days of systemic
Maximillian S Wu1, Wesley Kufel2, Scott Riddell3
1Division of Infectious Disease, Department of Medicine, SUNY Upstate Medical University, Syracuse, NY.
Abstract:
The typical duration of positive nucleic acid tests for methicillin-resistant Staphylococcus aureus (MRSA) in the nares of patients receiving systemic anti-MRSA antimicrobials is unknown. In this study, hospitalized adult patients with an initial positive MRSA nares nucleic acid test prescribed systemic anti-MRSA antimicrobials had follow-up testing done 48 to 96 hours later. A positive follow-up test was detected in 100/113 (88.5%), indicating that MRSA nares DNA tests still have utility for screening after patients have initiated anti-MRSA therapy.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) nasal DNA tests remain useful for screening even after patients start anti-MRSA medication. Most patients still tested positive for MRSA nasal DNA between 48 and 96 hours after beginning treatment.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Pharmacology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage is a significant risk factor for infection.
- The utility of MRSA nucleic acid amplification testing (NAAT) in nares during systemic antimicrobial therapy is not well-defined.
Purpose of the Study:
- To determine the duration of positive MRSA nares nucleic acid tests in hospitalized adult patients receiving systemic anti-MRSA antimicrobials.
Main Methods:
- Hospitalized adult patients with an initial positive MRSA nares NAAT were enrolled.
- Follow-up NAAT for MRSA in nares was performed 48 to 96 hours after initiating systemic anti-MRSA antimicrobial therapy.
Main Results:
- A positive follow-up MRSA nares NAAT was detected in 100 out of 113 patients (88.5%).
- This indicates a high rate of persistent MRSA nasal DNA detection despite ongoing anti-MRSA treatment.
Conclusions:
- MRSA nares NAAT retains utility for screening purposes even after the initiation of systemic anti-MRSA antimicrobial therapy.
- Nasal MRSA DNA detection may persist for several days despite treatment, suggesting potential challenges in rapid eradication.
