[Comparison between Phoenix system and agar-based methods for antimicrobial susceptibility testing of Streptococcus
L Martínez-Lamas1, M Treviño, P A Romero-Jung
1Servicio de Microbiología, Complejo Hospitalario Universitario, Santiago de Compostela (La Coruña).
Summary
The automated BD Phoenix system accurately identifies antibiotic susceptibility in streptococcal infections, offering rapid results within 12 hours. This diagnostic tool demonstrates high agreement with standard methods, aiding in effective treatment strategies.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Antibiotic resistance in streptococcal species poses a significant threat, particularly in severe infections.
- Rapid and accurate antimicrobial susceptibility testing (AST) is crucial for effective patient management.
Purpose of the Study:
- To evaluate the performance of the automated BD Phoenix system for AST in various streptococcal species.
- To compare the BD Phoenix system's results against established methods like CLSI disk-diffusion and Etest.
Main Methods:
- Antimicrobial susceptibility testing was performed on 200 clinical isolates of streptococci (beta-hemolytic, viridans, and S. pneumoniae).
- Results from the BD Phoenix system were compared with the Clinical Laboratory Standards Institute (CLSI) disk-diffusion method and Etest.
Main Results:
- The BD Phoenix system achieved over 96.7% categorical agreement with the disk-diffusion method for most streptococcal groups.
- Minor error rates were below 10% for all tested antibiotics.
- Penicillin susceptibility for viridans streptococci and S. pneumoniae showed 89.7% and 91.7% agreement with Etest, respectively.
Conclusions:
- The automated BD Phoenix system is a highly effective diagnostic tool for quantitative AST in streptococci.
- Its rapid turnaround time and high accuracy support its utility in clinical laboratories for guiding antibiotic therapy.
