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ElFeky DS, Gohar NM, El-Seidi EA, Ezzat MM, AboElew SH. Species identification and antifungal susceptibility pattern ofCandidaisolates in cases of vulvovaginal candidiasis. ALEXANDRIA JOURNAL OF MEDICINE 2019. [DOI: 10.1016/j.ajme.2015.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Dalia Saad ElFeky
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Egypt
| | - Noha Mahmoud Gohar
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Egypt
| | - Eman Ahmad El-Seidi
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Egypt
| | - Mona Mahmoud Ezzat
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Egypt
| | - Somaia Hassan AboElew
- Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Egypt
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Sampath A, Weerasekera M, Dilhari A, Gunasekara C, Bulugahapitiya U, Fernando N, Samaranayake L. Comparison of duplex PCR and phenotypic analysis in differentiating Candida dubliniensis from Candida albicans from oral samples. AMB Express 2017; 7:141. [PMID: 28658945 PMCID: PMC5487313 DOI: 10.1186/s13568-017-0435-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/16/2017] [Indexed: 11/17/2022] Open
Abstract
Candida dubliniensis shares a wide range of phenotypic characteristics with Candida albicans including a common trait called germ tube positivity. Hence, laboratory differentiation of these two species is cumbersome. Duplex PCR analyses for C. albicans and C. dubliniensis was performed directly on DNA extracted from a total of 122 germ tube positive isolates derived from 100 concentrated oral rinse samples from a random cohort of diabetics attending a clinic in Sri Lanka. These results were confirmed by DNA sequencing of internal transcribed spacer (ITS) region of rDNA of the yeasts. Performance efficacy of duplex PCR was then compared with phenotypic identification using a standard battery of phenotypic tests. Of the 122 germ tube positive isolates three were identified by duplex PCR as C. dubliniensis and the remainder as C. albicans. On the contrary, when the standard phenotypic tests, sugar assimilation and chlamydospore formation, were used to differentiate the two species 13 germ tube positive isolates were erroneously identified as C. dubliniensis. Duplex PCR was found to be rapid, sensitive and more specific than phenotypic identification methods in discriminating C. dubliniensis from C. albicans. This is also the first report on the oral carriage of C. dubliniensis in a Sri Lankan population.
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Methods of Candida dubliniensis identification and its occurrence in human clinical material. Folia Microbiol (Praha) 2017; 62:401-408. [DOI: 10.1007/s12223-017-0510-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 02/21/2017] [Indexed: 01/30/2023]
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Livério HO, Ruiz LDS, Freitas RSD, Nishikaku A, Souza ACD, Paula CR, Domaneschi C. Phenotypic and genotypic detection of Candida albicans and Candida dubliniensis strains isolated from oral mucosa of AIDS pediatric patients. Rev Inst Med Trop Sao Paulo 2017; 59:e14. [PMID: 28423089 PMCID: PMC5398186 DOI: 10.1590/s1678-9946201759014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 02/14/2017] [Indexed: 11/29/2022] Open
Abstract
The aim of this study was to assess a collection of yeasts to verify the presence of Candida dubliniensis among strains isolated from the oral mucosa of AIDS pediatric patients which were initially characterized as Candida albicans by the traditional phenotypic method, as well as to evaluate the main phenotypic methods used in the discrimination between the two species and confirm the identification through genotypic techniques, i.e., DNA sequencing. Twenty-nine samples of C. albicans isolated from this population and kept in a fungi collection were evaluated and re-characterized. In order to differentiate the two species, phenotypic tests (Thermotolerance tests, Chromogenic medium, Staib agar, Tobacco agar, Hypertonic medium) were performed and genotypic techniques using DNA sequencing were employed for confirmation of isolated species. Susceptibility and specificity were calculated for each test. No phenotypic test alone was sufficient to provide definitive identification of C. dubliniensis or C. albicans, as opposed to results of molecular tests. After amplification and sequencing of specific regions of the 29 studied strains, 93.1% of the isolates were identified as C. albicans and 6.9% as C. dubliniensis. The Staib agar assay showed a higher susceptibility (96.3%) in comparison with other phenotypic techniques. Therefore, genotypic methods are indispensable for the conclusive identification and differentiation between these species.
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Affiliation(s)
- Harisson Oliveira Livério
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Estomatologia, São Paulo, São Paulo, Brazil
| | | | - Roseli Santos de Freitas
- Universidade de São Paulo, Instituto de Medicina Tropical de São Paulo, São Paulo, São Paulo, Brazil
| | - Angela Nishikaku
- Universidade Federal de São Paulo, Laboratório Especial de Micologia, São Paulo, São Paulo, Brazil
| | - Ana Clara de Souza
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Estomatologia, São Paulo, São Paulo, Brazil
| | - Claudete Rodrigues Paula
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Estomatologia, São Paulo, São Paulo, Brazil
| | - Carina Domaneschi
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Estomatologia, São Paulo, São Paulo, Brazil
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Lu S, Mirchevska G, Phatak SS, Li D, Luka J, Calderone RA, Fonzi WA. Dynamic time warping assessment of high-resolution melt curves provides a robust metric for fungal identification. PLoS One 2017; 12:e0173320. [PMID: 28264030 PMCID: PMC5338801 DOI: 10.1371/journal.pone.0173320] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/17/2017] [Indexed: 12/16/2022] Open
Abstract
Fungal infections are a global problem imposing considerable disease burden. One of the unmet needs in addressing these infections is rapid, sensitive diagnostics. A promising molecular diagnostic approach is high-resolution melt analysis (HRM). However, there has been little effort in leveraging HRM data for automated, objective identification of fungal species. The purpose of these studies was to assess the utility of distance methods developed for comparison of time series data to classify HRM curves as a means of fungal species identification. Dynamic time warping (DTW), first introduced in the context of speech recognition to identify temporal distortion of similar sounds, is an elastic distance measure that has been successfully applied to a wide range of time series data. Comparison of HRM curves of the rDNA internal transcribed spacer (ITS) region from 51 strains of 18 fungal species using DTW distances allowed accurate classification and clustering of all 51 strains. The utility of DTW distances for species identification was demonstrated by matching HRM curves from 243 previously identified clinical isolates against a database of curves from standard reference strains. The results revealed a number of prior misclassifications, discriminated species that are not resolved by routine phenotypic tests, and accurately identified all 243 test strains. In addition to DTW, several other distance functions, Edit Distance on Real sequence (EDR) and Shape-based Distance (SBD), showed promise. It is concluded that DTW-based distances provide a useful metric for the automated identification of fungi based on HRM curves of the ITS region and that this provides the foundation for a robust and automatable method applicable to the clinical setting.
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Affiliation(s)
- Sha Lu
- Dermatology Department, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Gordana Mirchevska
- Institute for Microbiology and Parasitology, University Sts Cyril and Methodius, Skopje, Macedonia
| | - Sayali S. Phatak
- Department of Microbiology & Immunology, Georgetown University, Washington, DC, United States of America
| | - Dongmei Li
- Department of Microbiology & Immunology, Georgetown University, Washington, DC, United States of America
| | - Janos Luka
- Walter Reed Army Institute of Research (WRAIR), Silver Spring, MD, United States of America
| | - Richard A. Calderone
- Department of Microbiology & Immunology, Georgetown University, Washington, DC, United States of America
| | - William A. Fonzi
- Department of Microbiology & Immunology, Georgetown University, Washington, DC, United States of America
- * E-mail:
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Neppelenbroek KH, Seó RS, Urban VM, Silva S, Dovigo LN, Jorge JH, Campanha NH. Identification of
Candida
species in the clinical laboratory: a review of conventional, commercial, and molecular techniques. Oral Dis 2013; 20:329-44. [DOI: 10.1111/odi.12123] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/25/2013] [Accepted: 04/15/2013] [Indexed: 01/24/2023]
Affiliation(s)
- KH Neppelenbroek
- Department of Prosthodontics Bauru Dental School University of São Paulo‐USP Bauru São PauloBrazil
| | - RS Seó
- Department of Prosthodontics Varzea Grande School of Dentistry Varzea Grande Mato GrossoBrazil
| | - VM Urban
- Department of Dentistry Ponta Grossa State University‐UEPG Ponta Grossa Paraná Brazil
| | - S Silva
- Department of Biological Engineering Institute for Biotechnology and Bioengineering University of Minho Braga Portugal
| | - LN Dovigo
- Department of Social Dentistry Araraquara Dental School UNESP – Univ. Estadual Paulista Araraquara São PauloBrazil
| | - JH Jorge
- Department of Dental Materials and Prosthodontics Araraquara Dental School UNESP – Univ. Estadual Paulista Araraquara São Paulo Brazil
| | - NH Campanha
- Department of Dentistry Ponta Grossa State University‐UEPG Ponta Grossa Paraná Brazil
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Ahmad S, Khan Z, Asadzadeh M, Theyyathel A, Chandy R. Performance comparison of phenotypic and molecular methods for detection and differentiation of Candida albicans and Candida dubliniensis. BMC Infect Dis 2012; 12:230. [PMID: 23009343 PMCID: PMC3541108 DOI: 10.1186/1471-2334-12-230] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 09/24/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Candida albicans is the most pathogenic Candida species but shares many phenotypic features with Candida dubliniensis and may, therefore, be misidentified in clinical microbiology laboratories. Candidemia cases due to C. dubliniensis are increasingly being reported in recent years. Accurate identification is warranted since mortality rates are highest for C. albicans infections, however, C. dubliniensis has the propensity to develop resistance against azoles more easily. We developed a duplex PCR assay for rapid detection and differentiation of C. albicans from C. dubliniensis for resource-poor settings equipped with basic PCR technology and compared its performance with three phenotypic methods. METHODS Duplex PCR was performed on 122 germ tube positive and 12 germ tube negative isolates of Candida species previously identified by assimilation profiles on Vitek 2 ID-YST system. Typical morphologic characteristics on simplified sunflower seed agar (SSA), and reaction with a commercial (Bichro-Dubli) latex agglutination test were also performed. The assay was further applied on 239 clinical yeast and yeast-like fungi and results were confirmed by DNA sequencing of internal transcribed spacer (ITS) region of rDNA. RESULTS The results of duplex PCR assay for 122 germ tube positive and 12 germ tube negative isolates of Candida species were comparable to their identification by Vitek 2 ID-YST system, colony characteristics on SSA and latex agglutination test. Application of duplex PCR also correctly identified all 148 C. albicans and 50 C. dubliniensis strains among 239 yeast-like fungi. CONCLUSIONS The data show that both, duplex PCR and Bichro-Dubli are reliable tests for rapid (within few hours) identification of clinical yeast isolates as C. dubliniensis or C. albicans. However, duplex PCR may be applied directly on clinical yeast isolates for their identification as C. dubliniensis or C. albicans as it does not require prior testing for germ tube formation or latex Candida agglutination.
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Affiliation(s)
- Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
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Ellepola ANB, Khan ZU. Rapid differentiation of Candida dubliniensis from Candida albicans by early D-xylose assimilation. Med Princ Pract 2012; 21:375-8. [PMID: 22398877 DOI: 10.1159/000336586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 12/21/2011] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To determine if D-xylose (XYL) and/or α-methyl-D-glucoside (MDG) assimilation can be used reliably as a rapid test to differentiate Candida dubliniensis from Candida albicans at an earlier time point such as 2 h after inoculation. MATERIALS AND METHODS Thirty isolates of C. albicans and C. dubliniensis recovered from anatomical sites and clinical specimens were used. Isolates were inoculated into the API 20C AUX yeast identification system, and incubated at 30°C. XYL and MDG assimilations were read at 2-hour intervals beginning 2 h after the initial inoculation and up to 24 h of incubation; thereafter, results were read after 48 and 72 h. RESULTS Twenty-nine (97%) C. albicans isolates had assimilated XYL at 16 h and, by 24 h, all isolates were positive for XYL assimilation. None of the C. dubliniensis isolates assimilated XYL. The MDG assimilation revealed that 24, 40, 92 and 100% of C. albicans isolates became positive after 16, 24, 48 and 72 h of incubation, respectively, whereas only 3% of C. dubliniensis isolates assimilated MDG after 72 h. CONCLUSIONS The findings showed that it is possible to rapidly differentiate C. albicans from C. dubliniensis isolates using the API 20C AUX carbohydrate assimilation kits after 16 h of incubation at 30°C based on the XYL assimilation.
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Affiliation(s)
- A N B Ellepola
- Department of Bioclinical Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, Jabriya, Kuwait. arjuna @ hsc.edu.kw
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Lakner A, Essig A, Frickmann H, Poppert S. Evaluation of fluorescence in situ hybridisation (FISH) for the identification of Candida albicans in comparison with three phenotypic methods. Mycoses 2011; 55:e114-23. [PMID: 22126597 DOI: 10.1111/j.1439-0507.2011.02154.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Severe Candida infections are increasing and are associated with considerable morbidity and mortality. Rapid and accurate differentiation of Candida albicans from non-C. albicans species is essential for therapeutic decisions. We therefore developed a fluorescence in situ hybridisation (FISH) assay comprising previously described probes and a newly designed specific C. albicans probe/competitor probe combination. The FISH probes were first evaluated using 99 selected fungal strains covering 31 species, and a specificity between 96% and 100% and a sensitivity of 100%. The FISH assay was then applied to 110 clinical isolates in parallel with API32C, the chromogenic Candida ID agar, and determination of filamentous colony morphology. All tests produced highly reliable results. However, the Candida ID agar misidentified Candida dubliniensis as C. albicans. Determination of filamentous colony morphology allowed 100% reliable identification of C. albicans, but took 48 h. FISH allowed identification of clinical C. albicans isolates within 3 h with a sensitivity and specificity of 100%. FISH was additionally applied to 48 blood cultures showing yeasts in the Gram stain and correctly identified all 33 cases of C. albicans.
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Affiliation(s)
- Anna Lakner
- Institute of Medical Microbiology and Hygiene, University of Ulm, Germany
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