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Evaluation of the Pro-Lab ID ring system for the identification of medically important yeasts
A S Sekhon1, A A Padhye, A K Garg
1National Reference Centre for Human Mycotic Diseases, Provincial Laboratory of Public Health, University of Alberta, Edmonton, Canada.
Abstract:
We evaluated 151 coded isolates of medically important yeast species belonging to the genera Candida, Cryptococcus, Geotrichum, Rhodoturula, Saccharomyces and Torulopsis using the newly developed rapid Pro-Lab Identification Ring, PL 960 system (PLID-Ring). All isolates were concurrently identified by the API 20C and conventional procedures comprising macro- and micromorphology, assimilation and fermentation of various carbon and nitrogen compounds. The PLID-Ring system identified isolates of Candida albicans, C. kefyr, C. krusei, C. lusitaniae, C. parapsilosis, Rhodotorula rubra, and Torulopsis glabrata with 100% accuracy in 24 h. This system identified C guilliermondii and S. cerevisiae isolates with an accuracy of 90% and 86%, respectively, while those belonging to Cr. neoformans, T. candida (= C. famata), C. rugosa and C. tropicalis were identified with 38.4%, 50%, 12.5% and 50% accuracy, respectively. Three isolates of Cr. laurentii were not identified by the PLID-Ring system. The overall accuracy of the PLID-Ring system was 81.45% (123 of 151 isolates). However, the system does not include species such as Cr. laurentii in its data base. When these three Cr. laurentii isolates were excluded from the evaluation, the accuracy of the PLID-Ring system increased from 81.45% to 83.1%.
Insights
The Pro-Lab Identification Ring (PLID-Ring) system accurately identified most medically important yeasts within 24 hours. However, its overall accuracy was 81.45%, with notable limitations for certain Cryptococcus and Torulopsis species.
Area of Science:
- Medical Mycology
- Clinical Microbiology
- Diagnostic Technology
Background:
- Accurate identification of medically important yeast species is crucial for effective patient treatment and infection control.
- Conventional yeast identification methods can be time-consuming, necessitating the development of rapid diagnostic tools.
- The Pro-Lab Identification Ring, PL 960 system (PLID-Ring) was developed as a rapid method for yeast identification.
Purpose of the Study:
- To evaluate the accuracy and performance of the newly developed PLID-Ring system for identifying medically important yeast species.
- To compare the PLID-Ring system's results with established identification methods, including API 20C and conventional procedures.
- To determine the turnaround time and identify limitations of the PLID-Ring system.
Main Methods:
- 151 coded yeast isolates from genera Candida, Cryptococcus, Geotrichum, Rhodotorula, Saccharomyces, and Torulopsis were tested.
- Isolates were identified using the PLID-Ring system, API 20C, and conventional methods (macro/micromorphology, carbon/nitrogen assimilation/fermentation).
- Accuracy was calculated based on concordant results between the PLID-Ring system and reference methods.
Main Results:
- The PLID-Ring system achieved 100% accuracy for several Candida species, Rhodotorula rubra, and Torulopsis glabrata within 24 hours.
- Accuracies for Candida guilliermondii (90%) and Saccharomyces cerevisiae (86%) were high, but lower for Cryptococcus neoformans (38.4%), Torulopsis candida (50%), Candida rugosa (12.5%), and Candida tropicalis (50%).
- Three Cryptococcus laurentii isolates were not identified, and the overall accuracy was 81.45% (123/151), increasing to 83.1% when unidentifiable isolates were excluded.
Conclusions:
- The PLID-Ring system demonstrates high accuracy and speed for identifying common medically important yeasts.
- The system's current database and identification algorithms have limitations for certain species, notably Cryptococcus and some Candida species.
- Further development and database expansion are needed to improve the PLID-Ring system's comprehensive identification capabilities for a wider range of yeasts.