Comparing Methods for Identifying Coagulase-Negative Staphylococci
Author Information
Author(s): Kim Miyoung, Heo Se Ran, Choi Soon Hee, Kwon Hyelin, Park Jeong Su, Seong Moon-Woo, Lee Do-Hoon, Park Kyoung Un, Song Junghan, Kim Eui-Chong
Primary Institution: Seoul National University Hospital
Hypothesis
The accuracy of three phenotypic identification systems for coagulase-negative staphylococci (CNS) will be evaluated against 16S rRNA sequencing.
Conclusion
None of the three phenotypic systems tested could accurately and reliably identify CNS at the species level.
Supporting Evidence
- The MicroScan system identified 82.5% of isolates correctly, while VITEK 2 identified 87.5%, and Crystal GP identified 67.5%.
- Misidentification was a significant issue for MicroScan and Crystal GP systems.
- VITEK 2 had low-level discrimination issues with some S. epidermidis isolates.
- All systems had misidentifications, indicating that CNS identifications cannot always be considered accurate.
Takeaway
The study looked at different ways to identify certain bacteria, and none of the methods worked perfectly.
Methodology
The study compared three phenotypic identification systems (MicroScan, VITEK 2, and Crystal GP) against 16S rRNA sequencing for identifying 120 clinical isolates of coagulase-negative staphylococci.
Potential Biases
The Crystal GP system's manual reading could introduce bias, and the MicroScan database lacked certain species.
Limitations
Additional biochemical testing was not performed, and 16S rRNA sequencing may not perfectly distinguish between species.
Participant Demographics
The isolates included 95 from blood cultures and 25 from skin infections.
Digital Object Identifier (DOI)
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