Related Experiment Video
Updated: Apr 10, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Can Nasal Methicillin-Resistant Staphylococcus aureus Screening Be Used to Avoid Empiric Vancomycin Use in
Sara A Hennessy1, Puja M Shah1, Christopher A Guidry1
11 Department of Surgery, University of Virginia , Charlottesville, Virginia.
Background:
Vancomycin is used widely as empiric therapy for gram-positive organisms in patients with an intra-abdominal infection (IAI), even in those with no history of methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization. Potential adverse effects of vancomycin include nephrotoxicity, increased cost, and bacterial resistance. We hypothesized that MRSA nasal screening could be used to predict patients with a MRSA IAI and used to avoid unnecessary empiric vancomycin use.
Methods:
A surgical infections database collected prospectively from a single institution was reviewed for all IAIs between January 1, 2000-December 31, 2011. Patients with and without MRSA obtained from abdominal cultures as either a monomicrobial or polymicrobial isolate were compared by univariate analysis. A multivariable logistic regression was performed to identify independent predictors of MRSA IAI.
Results:
Of 2,591 patients with an IAI, 240 patients had a nasal MRSA screen within 30 d prior to infection and abdominal culture data, with an incidence of 23% for MRSA IAI. Patients with MRSA IAI (n=45) had more healthcare associated infections, lower white blood cell counts and greater rates of positive nasal MRSA screenings compared with those with non-MRSA IAI. By multivariable analysis (C statistic=0.908), the strongest independent predictor of an MRSA IAI was a positive MRSA screen (odds ratio [OR] 40.9, confidence interval [CI] 14.2-118.1). The positive predictive value for a MRSA screen was 53% whereas the negative predictive value of a MRSA screen was 97%.
Conclusion:
A negative MRSA nasal screen indicates with near certainty the absence of MRSA as part of an IAI. In the setting of a recent screen, empiric vancomycin can be withheld. Further, rapid MRSA nasal screening could be used to forego or to discontinue vancomycin therapy rapidly in the setting of IAI. This change in empiric antibiotic management of IAI may lead to decreased morbidity, reduction in cost, and a decrease in bacterial resistance.
Insights
A negative MRSA nasal screen reliably predicts the absence of MRSA in intra-abdominal infections, allowing clinicians to safely avoid unnecessary vancomycin. This approach can reduce costs and combat antibiotic resistance.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Surgical Infections
Background:
- Vancomycin is frequently used for Gram-positive intra-abdominal infections (IAI), despite potential harms like nephrotoxicity and resistance.
- Methicillin-resistant Staphylococcus aureus (MRSA) screening is not routinely used to guide empiric vancomycin therapy in IAI.
- Adverse effects of vancomycin and rising antibiotic resistance necessitate strategies to optimize its use.
Purpose of the Study:
- To evaluate the utility of MRSA nasal screening in predicting MRSA intra-abdominal infections (IAI).
- To determine if MRSA nasal screening can guide the avoidance of empiric vancomycin in IAI patients.
- To assess the impact of MRSA screening on antibiotic stewardship in IAI management.
Main Methods:
- A retrospective review of a surgical infections database from 2000-2011.
- Comparison of patients with and without MRSA IAI using univariate and multivariable logistic regression.
- Analysis of MRSA nasal screening results in relation to abdominal culture data.
Main Results:
- Of 2,591 IAI patients, 240 had MRSA screening data; 23% had MRSA IAI.
- Positive MRSA nasal screens were strongly associated with MRSA IAI (OR 40.9).
- The negative predictive value of MRSA nasal screening was high at 97%, while the positive predictive value was 53%.
Conclusions:
- A negative MRSA nasal screen accurately rules out MRSA as a cause of IAI.
- Empiric vancomycin can be safely withheld in patients with a recent negative MRSA nasal screen.
- Implementing rapid MRSA nasal screening can optimize vancomycin use, potentially reducing morbidity, costs, and resistance.
Related Concept Videos
01:25Clinical Significance of Antibiotic Resistance
01:25Mechanism of Antibiotic Resistance in MRSA
01:28Acute Pyelonephritis II: Diagnostic Studies and Management
01:29Staphylococcal Skin Infections
01:26Urine Studies II: Urine Culture and Sensitivity Test