Assessment of Two New Molecular Methods for Identification of Candida parapsilosis Sensu Lato Species

García‐Effrón, Guillermo; Cantón, Emilia; Pemán, Javier; Dilger, Amanda; Romá, Eva; Perlin, David S.

doi:10.1128/jcm.00508-11

Cited by 30 publications

(38 citation statements)

References 30 publications

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“…Although C. parapsilosis sensu stricto is responsible for the vast majority of human diseases associated with the three Candida species of the "psilosis" group, it is known that C. orthopsilosis and C. metapsilosis show antifungal susceptibility profiles different from that of C. parapsilosis that could affect therapeutic choices (25). To date, no commercial systems are currently available for this purpose (26,27), but the low rates of antifungal resistance in fungemias caused by C. orthopsilosis and C. metapsilosis strains (9, 12) may counterbalance this lack. Of note, no isolation of Candida nivariensis-two isolates were studied here-and Candida bracarensis was reported in those survey studies (9,12), in spite of the clinical, but moderate, interest elicited with respect to these C. glabrata-related species due to the propensity of some isolates to exhibit antifungal resistance (28).…”

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confidence: 99%

Comparative Evaluation of BD Phoenix and Vitek 2 Systems for Species Identification of Common and Uncommon Pathogenic Yeasts

et al. 2013

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The BD Phoenix system was evaluated for species-level identification of yeasts (250 clinical isolates) and compared with the Vitek 2 system, using ribosomal internal transcribed spacer (ITS) sequence analysis as the gold standard. Considering only the species included in each system's database, 96.3% (236/245) and 91.4% (224/245) of the isolates were correctly identified by BD Phoenix and Vitek 2, respectively. During the last decades, the growing number of vulnerable hosts such as critically ill or otherwise immunocompromised patients-e.g., individuals with advanced HIV infection or cancer who are undergoing transplant-has resulted in ever-increasing diagnoses of fungal infections (1, 2), including those caused by unusual opportunistic yeasts (3). Together with Candida albicans, the species most frequently isolated from clinical specimens (4, 5), other yeast species are increasingly recovered from patients with well-documented infections (6-8). They encompass non-albicans Candida species, including the rarer species Candida famata, Candida kefyr, Candida lipolytica, Candida rugosa, and Candida utilis, as well as uncommon species belonging to the genera Trichosporon, Rhodotorula, Pichia, Malassezia, and Saccharomyces (3).It was recently observed that some yeast species are highly virulent and show reduced susceptibility to one or several antifungal agents (2,3,(8)(9)(10)(11)(12) and that this has important clinical repercussions, often resulting in therapeutic failures (6, 13-15). Thus, accurate identification of these species is of utmost importance (16), but this goal is difficult to achieve, at least using conventional phenotypic methods (17,18). In contrast, the newly developed matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method may offer a highly discriminatory tool for identification of yeast isolates to the species level for C. albicans and Candida glabrata with unusual phenotypic or biochemical profiles as well (17), but to date its use has been curtailed or confined to large clinical microbiology laboratories (19).In this study, the performance of the BD Phoenix Yeast ID panel for use with the Phoenix system (Becton, Dickinson Diagnostics, Sparks, MD) was compared to that of the Vitek 2 colorimetric YST card for use with the Vitek 2 system (bioMérieux, Marcy l'Etoile, France) using a large collection of clinical isolates from common and less-common yeast species.(This work was presented in part at the 23rd European Congress of Clinical Microbiology and Infectious Diseases, Berlin, Germany, 27 to 30 April 2013.)A total of 250 selected isolates, representing 29 yeast species from seven genera (see Table S1 in the supplemental material), were routinely obtained from mycological cultures of clinical specimens (i.e., blood, cerebrospinal fluid, respiratory tract, stool, and urine) of individual patients hospitalized at the Università Cattolica del Sacro Cuore of Rome (Italy) during the calendar year 2012. Isolate identification was obtained as previously describ...

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Comparative Evaluation of BD Phoenix and Vitek 2 Systems for Species Identification of Common and Uncommon Pathogenic Yeasts

et al. 2013

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“…As current methods for yeast identification are based on phenotypic features, they can neither differentiate among the three closely related C. parapsilosis sensu lato species nor reliably discriminate isolates below the species level within the C. parapsilosis sensu stricto group. To ensure optimal therapeutic options and study nosocomial cross-transmission, molecular identification of C. parapsilosis outbreak isolates at the species level is therefore of utmost importance (10).…”

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Microsatellite Genotyping Clarified Conspicuous Accumulation of Candida parapsilosis at a Cardiothoracic Surgery Intensive Care Unit

et al. 2012

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Candida parapsilosis has become a significant cause of invasive fungal infections in seriously ill patients. Nosocomial outbreaks through direct and indirect contact have been described. The aim of this study was the molecular characterization of what appeared to be an ongoing C. parapsilosis outbreak at the cardiothoracic intensive care unit of the University Hospital of Vienna between January 2007 and December 2008. Using two different molecular typing methods-automated repetitive sequencebased PCR (DiversiLab; bioMérieux) and microsatellite genotyping-we investigated the genetic relationship of 99 C. parapsilosis isolates. Eighty-three isolates originated from the cardiothoracic intensive care unit, while 16 isolates were random control isolates from other intensive care units and a different Austrian hospital. The 99 C. parapsilosis isolates analyzed by repetitiveelement PCR all showed identical genotypes, suggesting an ongoing outbreak. In contrast, microsatellite genotyping showed a total of 56 different genotypes. Two major genotypes were observed in 10 and 15 isolates, respectively, whereas another 13 genotypes were observed in 2 to 4 isolates each. Forty-one genotypes were observed only once. Closely related genotypes that differed in only a single microsatellite marker were grouped into clonal complexes. When it comes to C. parapsilosis, microsatellite genotyping is a more discriminative method than repetitive-element PCR genotyping to investigate outbreaks.

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“…This method provides a rapid identification; however, the assay may exhibit low reproducibility because it is possible to observe variations in the melting curve when different thermocyclers are used (17). Garcia-Effron et al (11) proposed a new real-time PCR assay that can differentiate these 3 species using the molecular beacon technology and the ITS region as the target. This assay was highly specific, exhibited good reproducibility, and showed that the C. parapsilosis species complex can be identified quickly, thus demonstrating its suitability for clinical applications (11).…”

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confidence: 99%

“…These authors have shown that this method identifies the 3 species within the C. parapsilosis complex; however, a quality-controlled database must be available to provide an accurate analysis (29). In all methods described above, only limited numbers of C. metapsilosis isolates (1, 6, and 2, respectively) were tested by the authors (11,17,29). In our analysis, we were able to validate our strategy by testing 50 strains of C. parapsilosis (sensu stricto), 40 strains of C. orthopsilosis, and 10 strains of C. metapsilosis, including strains from 2 different countries.…”

Section: Discussionmentioning

confidence: 99%

Accurate Identification of Candida parapsilosis (Sensu Lato) by Use of Mitochondrial DNA and Real-Time PCR

et al. 2012

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Candida parapsilosis is the Candida species isolated the second most frequently from blood cultures in South America and some European countries, such as Spain. Since 2005, this species has been considered a complex of 3 closely related species: C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis. Here, we describe a real-time TaqMan-MGB PCR assay, using mitochondrial DNA (mtDNA) as the target, which readily distinguishes these 3 species. We first used comparative genomics to locate syntenic regions between these 3 mitochondrial genomes and then selected NADH5 as the target for the real-time PCR assay. Probes were designed to include a combination of different single-nucleotide polymorphisms that are able to differentiate each species within the C. parapsilosis complex. This new methodology was first tested using mtDNA and then genomic DNA from 4 reference and 5 clinical strains. For assay validation, a total of 96 clinical isolates and 4 American Type Culture Collection (ATCC) isolates previously identified by internal transcribed spacer (ITS) ribosomal DNA (rDNA) sequencing were tested. Real-time PCR using genomic DNA was able to differentiate the 3 species with 100% accuracy. No amplification was observed when DNA from other species was used as the template. We observed 100% congruence with ITS rDNA sequencing identification, including for 30 strains used in blind testing. This novel method allows a quick and accurate intracomplex identification of C. parapsilosis and saves time compared with sequencing, which so far has been considered the "gold standard" for Candida yeast identification. In addition, this assay provides a useful tool for epidemiological and clinical studies of these emergent species.

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Assessment of Two New Molecular Methods for Identification of Candida parapsilosis Sensu Lato Species

Cited by 30 publications

References 30 publications

Comparative Evaluation of BD Phoenix and Vitek 2 Systems for Species Identification of Common and Uncommon Pathogenic Yeasts

Comparative Evaluation of BD Phoenix and Vitek 2 Systems for Species Identification of Common and Uncommon Pathogenic Yeasts

Microsatellite Genotyping Clarified Conspicuous Accumulation of Candida parapsilosis at a Cardiothoracic Surgery Intensive Care Unit

Accurate Identification of Candida parapsilosis (Sensu Lato) by Use of Mitochondrial DNA and Real-Time PCR

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