Identification and Antifungal Susceptibility Profile of Candida guilliermondii and Candida fermentati from a Multicenter Study in China

Abstract

dWith molecular sequencing as a gold standard, the Vitek MS, Bruker Biotyper MS, and Vitek-2 Compact systems correctly identified 92.7%, 97.0%, and 15.2% of 164 Candida guillermondii isolates, respectively, and none of 8 C. fermentati isolates. All of the isolates showed high susceptibility to echinocandins, but some C. guilliermondii isolates showed low azole susceptibility. Invasive candidiasis (IC) is a public health threat worldwide and is considered a major cause of infection-related morbidity and mortality (1, 2). The incidence of candidemia due to Candida guilliermondii is low, ranging from 1% to 3%, depending on the geographic region (3, 4). However, the few available reports on C. guilliermondii infections indicate that these organisms are associated with poor clinical outcomes, which warrants further investigation (5-9).C. guilliermondii complex is a genetically heterogeneous group of phenotypically indistinguishable yeast species, including C. guilliermondii, C. fermentati, C. carpophila, and C. xestobii. Accurate and timely identification of C. guilliermondii complex isolates to the species level, including the associated antifungal susceptibility profiles, is essential for guiding clinical decisions (8). However, there is limited information on the performance of phenotypic methods like the Vitek-2 Compact (bioMérieux, France), and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems in the identification of species within the C. guilliermondii complex in China.C. guilliermondii complex isolates (n ϭ 172) collected from 40 hospitals in 18 provinces of China, under the China Hospital Invasive Fungal Surveillance Net (CHIF-NET) program (2010 to 2014), were studied. We evaluated the performance of the Vitek-2 Compact (bioMérieux, France) and two MALDI-TOF MS systems, including the Vitek MS system (IVD Knowledgebase version 2.0; bioMérieux) and the Bruker Autoflex Speed TOF/TOF MS system (with Biotyper version 3.1 software; Bruker Daltonics, USA) in the identification of C. guilliermondii complex isolates. Sequencing of the ribosomal DNA (rDNA) internal transcribed spacer (ITS) region was used as the gold standard (10).In vitro susceptibilities of the isolates to nine antifungal drugs were determined by the Sensititre YeastOne YO10 (Thermo Scientific, USA) system as per the manufacturer's instructions. MIC values were interpreted according to the CLSI document for echinocandins (11) and epidemiological cutoff values (ECVs) for the other agents (12). This study was approved by the relevant Human Research Ethics Committee (S-263).Isolates were derived from 172 patients (117 males and 55 females), with an average age of 54 Ϯ 23.1 years. Detailed information on the origin of the isolates (location and specimen type) is available in Table 1. The majority of the isolates were from surgical department (36.6%) and intensive care unit (ICU) (32.6%); patients admitted in these departments are more likely to have serious underlying disease or cancer or to be immunocom...

Candida guilliermondii Complex Is Characterized by High Antifungal Resistance but Low Mortality in 22 Cases of Candidemia

“…In previous studies, C. guilliermondii sensu stricto and C. fermentati accounted for approximately 90% to 95% and 4.5% to 9% of cases, respectively, with the remaining species of the complex playing a marginal role (less than 1%) (9,14). By contrast, we found a higher frequency of cases caused by C. fermentati (22.7%) and a lower frequency of cases caused by C. guilliermondii sensu stricto (77.2%).…”

“…The complex exhibited decreased in vitro susceptibility to all of the antifungal agents studied, with rates of resistance to fluconazole and other azoles of approximately 10% to 15% (9,12,14). Up to 10% of the isolates studied here were non-wild type according to the fluconazole ECOFF.…”

Breakthrough Candida guilliermondii (Meyerozyma guilliermondii) fungemia after cord blood transplantation for extranodal NK‐cell lymphoma with azole prophylaxis

“…18 Andes et al discussed, with their murine model, that prolonged exposure to azole drugs at non-lethal concentrations may be attributed to the emergence of resistant Candida infections. 19 Compared with the MICs shown previously, 20,21 the strain in the present case seemed to be more resistant to FLCZ and ITCZ, speaking in favor of the possible evolution of azole resistance during the long-term azole exposure before and after engraftment.…”

“…Andes et al discussed, with their murine model, that prolonged exposure to azole drugs at non‐lethal concentrations may be attributed to the emergence of resistant Candida infections . Compared with the MICs shown previously, the strain in the present case seemed to be more resistant to FLCZ and ITCZ, speaking in favor of the possible evolution of azole resistance during the long‐term azole exposure before and after engraftment. The present case may underline the needs to consider possible azole resistance among HCT recipients, especially those with history of prolonged azole exposure, and the importance of accurate identification of species and prompt examination of the susceptibility in such circumstances.…”

MALDI-TOF mass spectroscopy of yeasts and filamentous fungi for research and diagnostics in the agricultural value chain

“…Overall, MALDI-TOF MS is an accurate, reliable, and rapid method for the identification of human pathogenic fungi, and new applications for clinically relevant yeasts and filamentous fungi are continuously being developed [43][44][45]. A comparison of two commercially available systems, VITEK MS (bioMérieux) and MALDI Biotyper (Bruker Daltonics) with their associated databases, has shown similar identification efficiencies of clinically relevant yeasts for the two systems [46,47], while other studies found differences between biotyping systems [48,49]. The identification power is improved by including in-house generated reference spectra in the databases [17,43,46] (also see above).…”