Decrease in vancomycin MICs and prevalence of hGISA in MRSA and MSSA isolates from a German pediatric tertiary care...

Area of Science:

• Infectious Diseases
• Microbiology
• Clinical Pharmacy

Background:

• Vancomycin resistance in Staphylococcus aureus presents as MIC creep and heterogeneous GISA (hGISA).
• Increased vancomycin MICs are linked to poorer clinical outcomes.
• Regional variations in vancomycin resistance necessitate local surveillance.

Purpose of the Study:

• To analyze trends in vancomycin resistance, including MIC creep and hGISA prevalence.
• To evaluate vancomycin susceptibility over time in a German pediatric tertiary care hospital.

Main Methods:

• Retrospective analysis of Staphylococcus aureus isolates from 2002-2017.
• Measurement of vancomycin and oxacillin MICs using MIC test strips.
• Evaluation of GISA/hGISA prevalence and resistance trends over time.

Main Results:

• Vancomycin MICs decreased significantly from 1.11 in 2002-2009 to 0.99 in 2010-2017 (p < 0.001).
• hGISA prevalence decreased from 28% to 6% over the study period (p < 0.001).
• No significant difference in vancomycin MIC or hGISA prevalence was observed between MRSA and MSSA isolates.

Conclusions:

• A decreasing trend in vancomycin MIC values and hGISA prevalence was observed.
• Local monitoring of Staphylococcus aureus susceptibilities is crucial.
• Vancomycin remains a primary treatment for severe Gram-positive infections and MRSA.