Development of a standardized screening method for detection of vancomycin-resistant enterococci.
The incidence of vancomycin resistance among enterococci is increasing in the United States and elsewhere in the world, but automated susceptibility testing methods have difficulty detecting resistance expressed by certain strains. The agar screening method described by Willey et al. (B. M. Willey, B. N. Kreiswirth, A. E. Simor, G. Williams, S. R. Scriver, A. Phillips, and D. E. Low, J. Clin. Microbiol. 30:1621-1624, 1992) has been proposed as a reliable method for confirming vancomycin resistance. In this study, we investigated various parameters associated with the agar screening method and, on the basis of the findings, established optimum testing conditions for the method. First, to evaluate media and vancomycin concentrations, one laboratory used Mueller-Hinton and brain heart infusion agars supplemented with 4, 6, and 8 micrograms of vancomycin per ml to test 100 genetically characterized enterococcal strains. On the basis of the results obtained, brain heart infusion agar supplemented with 6 micrograms of vancomycin per ml was selected for further study. Subsequently, eight laboratories used the medium to test both reference and clinical isolates. There was very good performance with the reference strains and, among 158 clinical isolates tested, the method demonstrated sensitivity and specificity of 100% and from 96 to 99%, respectively.
Duke Scholars
Altmetric Attention Stats
Dimensions Citation Stats
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Vancomycin
- Species Specificity
- Sensitivity and Specificity
- Microbiology
- Microbial Sensitivity Tests
- Enterococcus
- Drug Resistance, Microbial
- Culture Media
- 3207 Medical microbiology
- 3202 Clinical sciences
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Vancomycin
- Species Specificity
- Sensitivity and Specificity
- Microbiology
- Microbial Sensitivity Tests
- Enterococcus
- Drug Resistance, Microbial
- Culture Media
- 3207 Medical microbiology
- 3202 Clinical sciences