Concordance analysis between different methodologies used for identification of oral isolates of Candida species

Abstract

Background: The yeasts species determination is fundamental not only for an accurate diagnosis but also for establishing a suitable patient treatment. We performed a concordance study of five methodologies for the species identification of oral isolates of Candida in Colombia. Methods: Sixty-seven Candida isolates were tested by; API® 20C-AUX, Vitek®2 Compact, Vitek®MS, Microflex® and a molecular test (panfungal PCR and sequencing). The commercial cost and processing time of the samples was done by graphical analysis. Results: Panfungal PCR differentiated 12 species of Candida, Vitek®MS and Microflex® methods identified 9 species, and API® 20C-AUX and Vitek®2 Compact methods identified 8 species each. Weighted Kappa (wK) showed a high agreement between Panfungal PCR, Vitek®MS, Microflex® and API® 20C-AUX (wK 0.62-0.93). The wK that involved the Vitek®2 Compact method presented moderate or good concordances compared with the other methods (wK 0.56-0.73). Methodologies based on MALDI TOF MS required 4 minutes to generate results and the Microflex® method had the lowest selling price. Conclusion: The methods evaluated showed high concordance in their results, being higher for the molecular methods and the methodologies based on MALDI TOF. The latter are faster and cheaper, presenting as promising alternatives for the routine identification of yeast species of the genus Candida.

Fungal infections diagnosis – Past, present and future

“… Laborious methods and time-consuming; Results are only provided after a few days; Low sensitivity to identify and distinguish emergent pathogenic species, such as C. auris. [ 64 , [66] , [67] , [68] , [69] , 72 , 73 , 177 ] Probable diagnosis (Serological methods) 1,3 β-D-glucan Detection of relevant fungal pathogens; Non-invasive; Fast results; High NPV is excellent for invasive fungal infections screening; Nonspecific panfungal test; Lower sensitivity and high number of false-positive results; Certain fungus produce less β-D-glucan ( Cryptococcus spp.) or do not produce any ( Blastomyces spp.…”

“…These are turbidimetric methods organized in cards with different microwells and the results are barcoded and compared with a database. However, before performing these methods, it is necessary to obtain a pure culture of the pathogen [ 64 ]. Considering fungal infections, these systems are most suitable for yeast species as for instance the manual API 20C AUX and the automated VITEK® 2 YST ID card (bioMérieux, Marcy-l’Étoile, France).…”

Especies y sensibilidad a antifúngicos de cepas de Candida spp. aisladas de la cavidad bucal de pacientes con VIH de Paraguay

“…El sistema automatizado VITEK ® 2 es un método confiable, simple y efectivo para la identificación de las especies del género Candida clínicamente relevantes, que permitió la identificación de levaduras no C. albicans, no C. dubliniensis. La desventaja es su costo elevado, además que con cierta frecuencia se requieren de pruebas adicionales para la identificación de especies con perfiles bioquímicos similares (26,27) .…”