Identification and Antifungal susceptibility testing of Candida species: A Comparison of Vitek-2 system with conventional and molecular methods

Abstract

Background:Candida infection is a major cause of morbidity and mortality in immunocompromised patients; an accurate and early identification is a prerequisite need to be taken as an effective measure for the management of patients. The purpose of this study was to compare the conventional identification of Candida species with identification by Vitek-2 system and the antifungal susceptibility testing (AST) by broth microdilution method with Vitek-2 AST system.Materials and Methods:A total of 172 Candida isolates were subjected for identification by the conventional methods, Vitek-2 system, restriction fragment length polymorphism, and random amplified polymorphic DNA analysis. AST was carried out as per the Clinical and Laboratory Standards Institute M27-A3 document and by Vitek-2 system.Results:Candida albicans (82.51%) was the most common Candida species followed by Candida tropicalis (6.29%), Candida krusei (4.89%), Candida parapsilosis (3.49%), and Candida glabrata (2.79%). With Vitek-2 system, of the 172 isolates, 155 Candida isolates were correctly identified, 13 were misidentified, and four were with low discrimination. Whereas with conventional methods, 171 Candida isolates were correctly identified and only a single isolate of C. albicans was misidentified as C. tropicalis. The average measurement of agreement between the Vitek-2 system and conventional methods was >94%. Most of the isolates were susceptible to fluconazole (88.95%) and amphotericin B (97.67%). The measurement of agreement between the methods of AST was >94% for fluconazole and >99% for amphotericin B, which was statistically significant (P < 0.01).Conclusion:The study confirmed the importance and reliability of conventional and molecular methods, and the acceptable agreements suggest Vitek-2 system an alternative method for speciation and sensitivity testing of Candida species infections.

Identification of Candida Species from Clinical Samples in a Honduran Tertiary Hospital

“…In India, the identification by PCR-RFLP of 150 strains from different clinical samples also showed a majority of Candida albicans, followed by C. glabrata, C. tropicalis, and C. parapsilosis. Kaur et al analyzed Candida strains isolated from six types of clinical samples, and also reported an important predominance of C. albicans [29]. Other studies have analyzed a single type of clinical sample, such as blood [30][31][32][33], urine [21,24], vulvovaginal secretion [34], bronchoalveolar fluid [35], and gastroesophageal tract [36]; however, in all of them the predominant species was C. albicans.…”

The New Mastitis Agents Emerged in Cattle in Turkey and An Investigation of Their Antimicrobial Susceptibility

“…A study was done as a way of evaluating the VITEK 2 Gram staining Gram (-) and Gram (+) with an identification card of VITEK 2 automated identification system (Kaur et al 2016). This card was crucial in the identification of fermenting and non-fermenting agent organisms such as Burkholderia pseudomallei and Burkholderia cepacia .…”

Identification of <em>Candida</em> Species from Clinical Samples in a Honduran Tertiary Hospital

“…analyzed Candida strains isolated from six types of clinical samples, and also reported an important predominance of C. albicans [29]. Other studies have analyzed a single type of clinical sample, such as blood [30][31][32][33], urine [21,24], vulvovaginal secretion [34], bronchoalveolar fluid [35], and gastroesophageal tract [36], however in all of them the predominant species was C. albicans.…”

“…Many studies have also shown high agreement between molecular findings and traditional phenotypic tests, such as chromogenic media and automated biochemical approaches [24,29,31,34,35,40,41]. Consequently, the gold standard for the diagnosis of Candida infections based on biochemical methods seems to be specific enough for a routine hospital diagnosis.…”