Related Experiment Videos
Vancomycin-resistant Staphylococcus aureus isolate from a patient in Pennsylvania
Fred C Tenover1, Linda M Weigel, Peter C Appelbaum
1Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. fnt1@cdc.gov
Antimicrobial Agents and Chemotherapy
|December 25, 2003
Summary
The second reported vancomycin-resistant Staphylococcus aureus (VRSA) isolate in the US was identified in Pennsylvania. This VRSA strain, belonging to the USA100 lineage, showed resistance to multiple antibiotics but remained susceptible to vancomycin via automated testing.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Vancomycin-resistant Staphylococcus aureus (VRSA) poses a significant threat due to limited treatment options.
- The emergence of VRSA necessitates continuous surveillance and characterization of new isolates.
Purpose of the Study:
- To characterize a newly identified vancomycin-resistant Staphylococcus aureus (VRSA) isolate from Pennsylvania.
- To determine the antimicrobial susceptibility profile and genetic relatedness of the VRSA isolate.
Main Methods:
- Species identification confirmed by biochemical tests and ribosomal DNA sequencing.
- Antimicrobial susceptibility testing using broth microdilution and macrodilution methods.
- Pulsed-field gel electrophoresis (PFGE) for genetic fingerprinting and PCR for resistance gene detection.
Main Results:
- The isolate was identified as Staphylococcus aureus and exhibited resistance to vancomycin (MIC = 32 µg/ml) and several other antibiotic classes.
- Susceptibility was observed for linezolid, minocycline, quinupristin-dalfopristin, rifampin, teicoplanin, and trimethoprim-sulfamethoxazole.
- PFGE analysis revealed the isolate belongs to the USA100 lineage, and PCR confirmed the presence of mecA and vanA genes on a 120-kb plasmid.
Conclusions:
- This represents the second reported VRSA isolate in the United States, highlighting the ongoing challenge of vancomycin resistance in S. aureus.
- The genetic characteristics of this isolate suggest a potential for dissemination within healthcare settings.