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Published on: September 5, 2013
Prevalence of methicillin-resistant Staphylococcus aureus : effect of different criteria for elimination of
Ledicia Álvarez-Paredes1, Natividad López-Riquelme, Juan Carlos Rodríguez
1S. Microbiología, Hospital General Universitario de Elche, Spain.
Background:
The purpose of this study is to compare the effect of different systems for eliminating duplicates in order to optimize the calculation of the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection.
Methods:
We compare the Clinical and Laboratory Standards Institute (CLSI) criterion, time criteria and the criterion recommended by the European Antimicrobial Surveillance System (EARSS).
Results:
Multiple isolates of MRSA are frequently recovered from successive cultures from the same patient (the average isolation rate of MRSA is 2.72), which demonstrates the importance of eliminating duplicates. When CLSI criterion data are compared to those obtained using other criteria, a significant increase in the number of S. aureus isolates was found applying time criteria (up to 36%) or the EARSS criterion (13%). There is also an increase in the methicillin resistance rate (between 3.31 and 3.96%; p < 0.01).
Conclusions:
We believe that the EARSS method, with the proper quality controls and latest software tools available, is the best for determining the true situation of MRSA.
Insights
Duplicate elimination methods significantly impact methicillin-resistant Staphylococcus aureus (MRSA) infection prevalence calculations. The European Antimicrobial Surveillance System (EARSS) method is recommended for accurate MRSA surveillance.
Area of Science:
- Medical Microbiology
- Infectious Disease Epidemiology
- Antimicrobial Resistance
Background:
- Accurate calculation of methicillin-resistant Staphylococcus aureus (MRSA) infection prevalence is crucial for public health.
- Duplicate isolates can skew prevalence data, necessitating effective duplicate elimination strategies.
Purpose of the Study:
- To compare the effectiveness of different duplicate elimination systems for optimizing MRSA prevalence calculations.
- To identify the most reliable method for determining the true prevalence of MRSA infections.
Main Methods:
- Comparison of three duplicate elimination criteria: Clinical and Laboratory Standards Institute (CLSI), time-based criteria, and the European Antimicrobial Surveillance System (EARSS) criterion.
- Analysis of MRSA isolate data to assess the impact of each criterion on prevalence and resistance rates.
Main Results:
- Multiple MRSA isolates from the same patient are common, highlighting the need for duplicate elimination.
- Time criteria and EARSS criteria significantly increased S. aureus isolate counts (up to 36% and 13%, respectively) compared to CLSI.
- Methicillin resistance rates also increased, ranging from 3.31% to 3.96% (p < 0.01) with these methods.
Conclusions:
- The European Antimicrobial Surveillance System (EARSS) method is considered superior for accurately determining MRSA prevalence.
- Implementation of EARSS with robust quality controls and modern software enhances the reliability of MRSA surveillance data.
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