A Study of Vancomycin and Daptomycin Minimum Inhibitory Concentration in Clinical Isolates of Staphylococcus Aureus At A Tertiary Care Hospital of Gujarat
Keywords:
Staphylococcus aureus, Vancomycin, Daptomycin, Minimum Inhibitory ConcentrationAbstract
Background and objectives: Persistent use of Vancomycin in Staphylococcus aureus infections may lead to increase in minimum inhibitory concentration (MIC) levels and thereby failure of treatment. We determined Vancomycin MIC in these strains to identify the need to switch over to other options of treatment like Daptomycin. Methods: All isolates of Staphylococcus aureus from 1st January 2017 to 31st January 2017 were tested with Vitek 2 automated system and MIC of Vancomycin and Daptomycin was determined using E-strips. Patient related information was collected using a structured proforma. Results: For a total of 85 Staphylococcus aureus isolates, the geometric mean for Vancomycin MIC was 0.68 mg/L, the modal MIC was 1 mg/L, the MIC50 and MIC90 values were 0.5 mg/L and 1 mg/L respectively and 55% of isolates had Vancomycin MIC of ≤ 0.5 mg/L. The geometric mean for Daptomycin MIC was 0.34 mg/L, the modal MIC was 0.25 mg/L, the MIC50 and MIC90 were 0.25 mg/L and 0.5 mg/L respectively and 77% of isolates had Daptomycin MIC of ≤ 0.5 mg/L. Interpretation and conclusion: The MIC of Vancomycin has been at the lower side of susceptible range and therefore could be continued as drug of choice in Staphylococcus aureus infections.
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