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Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method.
J Clin Microbiol 2015; 53(6):1823-30JC

Abstract

Candida auris is a multidrug-resistant yeast that causes a wide spectrum of infections, especially in intensive care settings. We investigated C. auris prevalence among 102 clinical isolates previously identified as Candida haemulonii or Candida famata by the Vitek 2 system. Internal transcribed spacer region (ITS) sequencing confirmed 88.2% of the isolates as C. auris, and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) easily separated all related species, viz., C. auris (n = 90), C. haemulonii (n = 6), C. haemulonii var. vulnera (n = 1), and Candida duobushaemulonii (n = 5). The in vitro antifungal susceptibility was determined using CLSI broth microdilution (CLSI-BMD), the Vitek 2 antifungal susceptibility test, and the Etest method. C. auris isolates revealed uniformly elevated fluconazole MICs (MIC50, 64 μg/ml), and an alarming percentage of isolates (37%) exhibited elevated caspofungin MICs by CLSI-BMD. Notably, 34% of C. auris isolates had coexisting elevated MICs (≥2 μg/ml) for both fluconazole and voriconazole, and 10% of the isolates had elevated coexisting MICs (≥2 μg/ml) to two additional azoles, i.e., posaconazole and isavuconazole. In contrast to reduced amphotericin B MICs by CLSI-BMD (MIC50, 1 μg/ml) for C. auris, elevated MICs were noted by Vitek 2 (MIC50, 8 μg/ml), which were statistically significant. Candida auris remains an unnoticed pathogen in routine microbiology laboratories, as 90% of the isolates characterized by commercial identification systems are misidentified as C. haemulonii. MALDI-TOF MS proved to be a more robust diagnostic technique for rapid identification of C. auris. Considering that misleading elevated MICs of amphotericin B by the Vitek AST-YS07 card may lead to the selection of inappropriate therapy, a cautionary approach is recommended for laboratories relying on commercial systems for identification and antifungal susceptibility testing of rare yeasts.

Authors+Show Affiliations

Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.Department of Microbiology, Amrita Institute of Medical Sciences & Research Centre, Kochi, Kerala, India.Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands.Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India dranuradha@hotmail.com.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25809970

Citation

Kathuria, Shallu, et al. "Multidrug-Resistant Candida Auris Misidentified as Candida Haemulonii: Characterization By Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability By Vitek 2, CLSI Broth Microdilution, and Etest Method." Journal of Clinical Microbiology, vol. 53, no. 6, 2015, pp. 1823-30.
Kathuria S, Singh PK, Sharma C, et al. Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method. J Clin Microbiol. 2015;53(6):1823-30.
Kathuria, S., Singh, P. K., Sharma, C., Prakash, A., Masih, A., Kumar, A., ... Chowdhary, A. (2015). Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method. Journal of Clinical Microbiology, 53(6), pp. 1823-30. doi:10.1128/JCM.00367-15.
Kathuria S, et al. Multidrug-Resistant Candida Auris Misidentified as Candida Haemulonii: Characterization By Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability By Vitek 2, CLSI Broth Microdilution, and Etest Method. J Clin Microbiol. 2015;53(6):1823-30. PubMed PMID: 25809970.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method. AU - Kathuria,Shallu, AU - Singh,Pradeep K, AU - Sharma,Cheshta, AU - Prakash,Anupam, AU - Masih,Aradhana, AU - Kumar,Anil, AU - Meis,Jacques F, AU - Chowdhary,Anuradha, Y1 - 2015/03/25/ PY - 2015/02/11/received PY - 2015/03/17/accepted PY - 2015/3/27/entrez PY - 2015/3/27/pubmed PY - 2016/3/15/medline SP - 1823 EP - 30 JF - Journal of clinical microbiology JO - J. Clin. Microbiol. VL - 53 IS - 6 N2 - Candida auris is a multidrug-resistant yeast that causes a wide spectrum of infections, especially in intensive care settings. We investigated C. auris prevalence among 102 clinical isolates previously identified as Candida haemulonii or Candida famata by the Vitek 2 system. Internal transcribed spacer region (ITS) sequencing confirmed 88.2% of the isolates as C. auris, and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) easily separated all related species, viz., C. auris (n = 90), C. haemulonii (n = 6), C. haemulonii var. vulnera (n = 1), and Candida duobushaemulonii (n = 5). The in vitro antifungal susceptibility was determined using CLSI broth microdilution (CLSI-BMD), the Vitek 2 antifungal susceptibility test, and the Etest method. C. auris isolates revealed uniformly elevated fluconazole MICs (MIC50, 64 μg/ml), and an alarming percentage of isolates (37%) exhibited elevated caspofungin MICs by CLSI-BMD. Notably, 34% of C. auris isolates had coexisting elevated MICs (≥2 μg/ml) for both fluconazole and voriconazole, and 10% of the isolates had elevated coexisting MICs (≥2 μg/ml) to two additional azoles, i.e., posaconazole and isavuconazole. In contrast to reduced amphotericin B MICs by CLSI-BMD (MIC50, 1 μg/ml) for C. auris, elevated MICs were noted by Vitek 2 (MIC50, 8 μg/ml), which were statistically significant. Candida auris remains an unnoticed pathogen in routine microbiology laboratories, as 90% of the isolates characterized by commercial identification systems are misidentified as C. haemulonii. MALDI-TOF MS proved to be a more robust diagnostic technique for rapid identification of C. auris. Considering that misleading elevated MICs of amphotericin B by the Vitek AST-YS07 card may lead to the selection of inappropriate therapy, a cautionary approach is recommended for laboratories relying on commercial systems for identification and antifungal susceptibility testing of rare yeasts. SN - 1098-660X UR - https://www.unboundmedicine.com/medline/citation/25809970/Multidrug_Resistant_Candida_auris_Misidentified_as_Candida_haemulonii:_Characterization_by_Matrix_Assisted_Laser_Desorption_Ionization_Time_of_Flight_Mass_Spectrometry_and_DNA_Sequencing_and_Its_Antifungal_Susceptibility_Profile_Variability_by_Vitek_2_CLSI_Broth_Microdilution_and_Etest_Method_ L2 - http://jcm.asm.org/cgi/pmidlookup?view=long&pmid=25809970 DB - PRIME DP - Unbound Medicine ER -