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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Published on: May 8, 2013

Prevalence and clinical implications of Staphylococcus aureus with a vancomycin MIC of 4 microg/ml in Korea

Hong Bin Kim1, Yeong Seon Lee, Bong Su Kim

  • 1Department of Microbiology, National Institute of Health, Seoul 122-701, Republic of Korea.

Microbial Drug Resistance (Larchmont, N.Y.)
|April 6, 2006
PubMed

Insights

Methicillin-resistant Staphylococcus aureus (MRSA) with vancomycin MIC of 4 microg/ml is rare, found in 0.5% of isolates. Chronic osteomyelitis was the most common infection, often linked to prolonged glycopeptide exposure.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Clinical Medicine

Background:

  • Vancomycin-intermediate Staphylococcus aureus (VISA) and vancomycin resistance are clinical concerns.
  • Staphylococcus aureus isolates with a vancomycin Minimum Inhibitory Concentration (MIC) of 4 microg/ml can cause treatment failure.
  • Understanding the prevalence and characteristics of such isolates is crucial for effective patient management.

Purpose of the Study:

  • To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) with a vancomycin MIC of 4 microg/ml in Korea.
  • To clarify the clinical features of infections caused by these specific MRSA isolates.

Main Methods:

  • Nationwide surveillance of 27 hospitals in Korea over 8 weeks (April-May 2001).
  • Screening of isolates on brain-heart infusion agar with 4 microg/ml vancomycin.
  • Review of medical records for patients with identified MRSA isolates (vancomycin MIC 4 microg/ml).

Main Results:

  • No vancomycin-intermediate Staphylococcus aureus (VISA) or vancomycin-resistant Staphylococcus aureus (VRSA) detected among 3,756 MRSA isolates.
  • Eighteen isolates (0.5%) exhibited MRSA with a vancomycin MIC of 4 microg/ml.
  • Twelve patients had infections (8 chronic osteomyelitis, 1 surgical site, 1 pneumonia, 1 intra-abdominal, 1 catheter-related); 5 were colonized.
  • Prolonged glycopeptide exposure (median 56 days) was noted in 11 cases.
  • Only 1 patient achieved culture-negativity; 2 patients died from S. aureus infections.

Conclusions:

  • MRSA with a vancomycin MIC of 4 microg/ml is a rare finding.
  • Chronic osteomyelitis is the predominant infection type associated with these isolates.
  • Reduced vancomycin susceptibility in MRSA may be linked to prolonged glycopeptide exposure.

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