Phenotypic and genotypic characterization of Candida species isolated from candideamia in Iran

Abstract

Background and Purpose:Candidemia is one of the most important fungal infections caused by Candida species. Infections and mortality caused by Candida species have been on a growing trend during the past two decades. The resistance of yeasts to antifungal drugs and their epidemiological issues have highlighted the importance of accurately distinguishing the yeasts at the species level. The technique applied for yeast identification should be fast enough to facilitate the imminent initiation of the appropriate therapy. Candidemia has not been studied comprehensively in Iran yet. Regarding this, the current study aimed to assess the epidemiology of candidemia at Tehran hospitals and compare the results with the previous findings.Materials and Methods:This study was conducted on 204 positive blood cultures obtained from 125 patients hospitalized in several hospitals located in Tehran, Iran, within a period of 13 months. The yeast isolation and species identification were accomplished using several phenotypic methods (i.e., production of germ tube in human serum, culture on CHROMagar Candida, and Corn meal agar containing Tween 80) and molecular methods, such as polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In addition, unknown cases were subjected to PCR sequencing. These methods were then compared in terms of accuracy, sensitivity, and speed of identification.Results:According to the results, C. albicans (62.4%) was the most common isolate, followed by C. parapsilosis (n=36, 17.5%), C. glabrata (n=18, 8.8%), C. tropicalis (n=13, 6.3%), Trichosporon asahii (n=3, 1.5%), C. kefyr (n=2, 1.0%), C. lusitaniae (n=2, 1.0%), C. intermedia (n=1, 0.5%), C. guilliermondii (n=1, 0.5%), and C. krusei (n=1, 0.5%), respectively. Conclusion:As the findings indicated, the most common species causing candidemia were C. albicans, C. parapsilosis, and C. glabrata, respectively. Children less than one year old and people with cancer were at higher risk for candidemia, compared to other groups. Moreover, phenotypic and molecular methods resulted in the identification of 65.2% and 96.6% of the isolates, respectively. Consequently, PCR-RFLP could be concluded as a more favorable technique for species identification.

Identification of Cryptic Species of Four Candida Complexes in a Culture Collection

“…Identification of yeasts at the species level is a challenge for clinical microbiologists who work for health centers in low-income countries due to the lack of appropriate technologies. Conventional methods based on phenotypic or biochemical characteristics are sometimes insufficient to provide an accurate identification of the etiological agent of an infection [38,39]. Reports of novel Candida species could be clinically relevant because they could differ both in virulence and in the spectrum of antifungal resistance [40].…”

Update of the list of QPS‐recommended biological agents intentionally added to food or feed as notified to EFSA 10: Suitability of taxonomic units notified to EFSA until March 2019

“…For 32 of those 45 studies, no potential safety concern was reported, while a potential safety concern was described in the other 13 studies (corresponding to 11 articles: Diba et al., ; Das et al., ; Jung et al., ; Kara et al., ; Khedri et al., ; Nagy et al., ; Omran and Mansori, ; Sadrossadati et al., ; Afsarian et al., ; Shokohi et al., ; Teblick et al., ): 3 for C. famata (Das et al., ; Diba et al., ; Shokohi et al., ), 7 for C. kefyr (Afsarian et al., ; Diba et al., ; Khedri et al., ; Nagy et al., ; Omran and Mansori, ; Sadrossadati et al., ; Shokohi et al., ), 1 for C. pelliculosa (Jung et al., ) and 2 for Saccharomyces cerevisiae (Kara et al., ; Teblick et al., ). All these studies reported isolation of the QPS yeasts from opportunistic infections in patients with serious predisposing factors.…”

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.…”

“…Candida ® , and detected 9.3% of inconsistencies mostly attributable to the phenotypic method. A study in which several methods were compared, including a chromogenic medium and PCR-RFLP, determined 2.5% inconsistency between the assays [31]. Jafari et al compared CHROMagar Candida ® and two molecular assays.…”