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Nanomechanics of Drug-target Interactions and Antibacterial Resistance Detection
Published on: October 25, 2013
Correlation between vancomycin and daptomycin MIC values for methicillin-susceptible and methicillin-resistant
Rebecca A Keel1, Christina A Sutherland, Jaber Aslanzadeh
1Center for Anti-Infective Research and Development, Hartford, CT 06102, USA.
Diagnostic Microbiology and Infectious Disease
|October 20, 2010
Summary
This study found a weak correlation between vancomycin and daptomycin minimum inhibitory concentrations (MICs) for Staphylococcus aureus using Etest and broth microdilution methods. MicroScan showed no significant correlation, impacting vancomycin-resistant Staphylococcus aureus treatment strategies.
Area of Science:
- Clinical microbiology
- Infectious diseases
- Pharmacology
Background:
- Vancomycin and daptomycin are critical antibiotics for treating Staphylococcus aureus infections.
- Accurate minimum inhibitory concentration (MIC) determination is essential for guiding therapy.
- Evaluating the correlation between vancomycin and daptomycin MICs can inform treatment strategies, especially for challenging infections.
Purpose of the Study:
- To investigate the correlation between vancomycin and daptomycin MICs in Staphylococcus aureus isolates.
- To compare the performance of different MIC testing methods (broth microdilution, Etest, MicroScan) in detecting this correlation.
Main Methods:
- Analysis of 298 Staphylococcus aureus isolates.
- Determination of vancomycin and daptomycin MICs using broth microdilution (BMD), Etest, and MicroScan(®).
- Statistical analysis to assess the correlation (Spearman's rank correlation coefficient, ρ) between MIC values obtained from different methods.
Main Results:
- A significant but poor correlation was observed between vancomycin and daptomycin MICs using Etest (ρ = 0.29, P < .01) and BMD (ρ = 0.15, P = .01).
- No significant correlation was found between vancomycin and daptomycin MICs when using the MicroScan(®) method (ρ = 0.08, P = .18).
- These findings highlight method-dependent variability in assessing antibiotic susceptibility.
Conclusions:
- The correlation between vancomycin and daptomycin MICs in Staphylococcus aureus is method-dependent.
- Etest and BMD show a weak correlation, suggesting potential for predicting cross-resistance or co-resistance.
- MicroScan(®) may not reliably detect this correlation, emphasizing the importance of method selection in clinical microbiology laboratories for guiding antibiotic therapy.
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