scholarly journals Candida auris Clinical Isolates from South Korea: Identification, Antifungal Susceptibility, and Genotyping

2019 ◽  
Vol 57 (4) ◽  
Author(s):  
Yong Jun Kwon ◽  
Jong Hee Shin ◽  
Seung A Byun ◽  
Min Ji Choi ◽  
Eun Jeong Won ◽  
...  
Keyword(s):  
Antifungal Susceptibility ◽  
Diagnostic Tools ◽  
Candida Auris ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Fluconazole Resistant ◽  
Vitek 2 ◽  
Vitek Ms ◽  
Tof Ms

ABSTRACT Candida auris is an emerging worldwide fungal pathogen. Over the past 20 years, 61 patient isolates of C. auris (4 blood and 57 ear) have been obtained from 13 hospitals in Korea. Here, we reanalyzed those molecularly identified isolates using two matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) systems, including Biotyper and Vitek MS, followed by antifungal susceptibility testing, sequencing of the ERG11 gene, and genotyping. With a research-use-only (RUO) library, 83.6% and 93.4% of the isolates were correctly identified by Biotyper and Vitek MS, respectively. Using an in vitro diagnostic (IVD) library of Vitek MS, 96.7% of the isolates were correctly identified. Fluconazole-resistant isolates made up 62.3% of the isolates, while echinocandin- or multidrug-resistant isolates were not found. Excellent essential (within two dilutions, 96.7%) and categorical agreements (93.4%) between the Clinical and Laboratory Standards Institute (CLSI) and Vitek 2 (AST-YS07 card) methods were observed for fluconazole. Sequencing ERG11 for all 61 isolates revealed that only 3 fluconazole-resistant isolates showed the Erg11p amino acid substitution K143R. All 61 isolates showed identical multilocus sequence typing (MLST). Pulsed-field gel electrophoresis (PFGE) analyses revealed that both blood and ear isolates had the same or similar patterns. These results show that MALDI-TOF MS and Vitek 2 antifungal susceptibility systems can be reliable diagnostic tools for testing C. auris isolates from Korean hospitals. The Erg11p mutation was seldom found among Korean isolates of C. auris, and multidrug resistance was not found. Both MLST and PFGE analyses suggest that these isolates are genetically similar.

scholarly journals Identificación de aislamientos de Candida auris recuperados a través de la vigilancia por laboratorio en Colombia: un reto para el diagnóstico

Infectio ◽  
2020 ◽  
Vol 24 (4) ◽  
pp. 224
Author(s):  
Silvia K. Carvajal-Valencia ◽  
Diana Lizarazo ◽  
Carolina Duarte ◽  
Patricia Escandon
Keyword(s):  
Candida Auris ◽  
Candida Spp ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Vitek 2 ◽  
Bruker Daltonics ◽  
Tof Ms

Objetivo: Comparar los resultados obtenidos de diferentes sistemas de identificación de C. auris.Métodos: Análisis descriptivo con datos recopilados durante 2016-19 mediante la vigilancia nacional. Se evaluaron los resultados generados por los sistemas MicroScan, Phoenix BD, VITEK 2 y MALDI-TOF MS de instituciones hospitalarias de 843 aislamientos clínicos sospechosos de C. auris remitidos al INS y se compararon con los resultados generados de confirmación a través de MALDI- TOF MS (Bruker Daltonics) o PCR. Resultados: De los 843 aislamientos clínicos remitidos al INS, el 81,7% fueron confirmados como C. auris mediante MALDI- TOF MS o PCR en el INS y el resto, 18,3%, fueron identificados como otras especies de Candida spp. Las identificaciones correctas enviadas por los laboratorios representaron el 42,4%. MicroScan identificó C. auris principalmente como C. haemulonii, C. guilliermondii, C. albicans y C. famata; Phoenix BD, VITEK 2 y MALDI-TOF MS identificó C. auris como C. haemulonii. Discusión: Estudios señalan que C. auris exhibe una estrecha relación filogenética con C. haemulonii. Las identificaciones discrepantes pueden darse debido a que las bases de datos de los sistemas de diagnóstico son limitadas para este patógeno. Las deficiencias de los sistemas comerciales para la identificación de C. auris deben ser complementados con otros sistemas como MALDI-TOF MS o pruebas moleculares.

scholarly journals Antifungal Susceptibility Testing of Aspergillus spp. by Using a Composite Correlation Index (CCI)-Based Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method Appears To Not Offer Benefit over Traditional Broth Microdilution Testing

2017 ◽  
Vol 55 (7) ◽  
pp. 2030-2034 ◽  
Author(s):  
Melissa R. Gitman ◽  
Lisa McTaggart ◽  
Joanna Spinato ◽  
Rahgavi Poopalarajah ◽  
Erin Lister ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Laser Desorption Ionization ◽  
Wild Type ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

ABSTRACT Aspergillus spp. cause serious invasive lung infections, and Aspergillus fumigatus is the most commonly encountered clinically significant species. Voriconazole is considered to be the drug of choice for treating A. fumigatus infections; however, rising resistance rates have been reported. We evaluated a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based method for the differentiation between wild-type and non-wild-type isolates of 20 Aspergillus spp. (including 2 isolates of Aspergillus ustus and 1 of Aspergillus calidoustus that were used as controls due their intrinsic low azole susceptibility with respect to the in vitro response to voriconazole). At 30 and 48 h of incubation, there was complete agreement between Cyp51A sequence analysis, broth microdilution, and MALDI-TOF MS classification of isolates as wild type or non-wild type. In this proof-of-concept study, we demonstrated that MALDI-TOF MS can be used to accurately detect A. fumigatus strains with reduced voriconazole susceptibility. However, rather than proving to be a rapid and simple method for antifungal susceptibility testing, this particular MS-based method showed no benefit over conventional testing methods.

scholarly journals Evaluating and Improving Vitek MS for Identification of Clinically Relevant Species of Trichosporon and the Closely Related Genera Cutaneotrichosporon and Apiotrichum

2017 ◽  
Vol 55 (8) ◽  
pp. 2439-2444 ◽  
Author(s):  
João N. de Almeida ◽  
Viviane M. Favero Gimenes ◽  
Elaine C. Francisco ◽  
Lumena P. Machado Siqueira ◽  
Renato K. Gonçalves de Almeida ◽  
...  
Keyword(s):  
Species Identification ◽  
Large Set ◽  
Spectral Profile ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Microorganism Identification ◽  
Vitek Ms ◽  
Tof Ms

ABSTRACT Trichosporon species are relevant etiologic agents of hospital-acquired infections. High mortality rates are attributed to Trichosporon deep-seated infections in immunocompromised individuals, making fast and accurate species identification relevant for hastening the discovery of best-targeted therapy. Recently, Trichosporon taxonomy has been reassessed, and three genera have been proposed for the pathogenic species: Trichosporon , Cutaneotrichosporon , and Apiotrichum . Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has replaced old phenotypic methods for microorganism identification in clinical laboratories, but spectral profile databases have to be evaluated and improved for optimal species identification performance. Vitek MS (bioMérieux) is one of the commercially available MALDI-TOF MS platforms for pathogen identification, and its spectral profile databases remain poorly evaluated for Trichosporon , Cutaneotrichosporon , and Apiotrichum species identification. We herein evaluated and improved Vitek MS for the identification of the main clinical relevant species of Trichosporon , Cutaneotrichosporon , and Apiotrichum using a large set of strains and isolates belonging to different yeast collections in Brazil and France.

scholarly journals Evaluation of Vitek MS for Differentiation of Cryptococcus neoformans and Cryptococcus gattii Genotypes

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Lumena P. Machado Siqueira ◽  
Viviane M. Favero Gimenes ◽  
Roseli Santos de Freitas ◽  
Márcia de Souza Carvalho Melhem ◽  
Lucas Xavier Bonfietti ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Cryptococcus Gattii ◽  
Correct Identification ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Mass Spectral ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Tof Ms

ABSTRACT Cryptococcus neoformans and Cryptococcus gattii are the main pathogenic species of invasive cryptococcosis among the Cryptococcus species. Taxonomic studies have shown that these two taxa have different genotypes or molecular types with biological and ecoepidemiological peculiarities. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been proposed as an alternative method for labor-intensive methods for C. neoformans and C. gattii genotype differentiation. However, Vitek MS, one of the commercial MALDI-TOF MS instruments, has not been yet been evaluated for this purpose. Thus, we constructed an in-house database with reference strains belonging to the different C. neoformans (VNI, VNII, VNIII, and VNIV) and C. gattii (VGI, VGII, VGIII, and VGIV) major molecular types by using the software Saramis Premium (bioMérieux, Marcy-l’Etoile, France). Then, this new database was evaluated for discrimination of the different genotypes. Our in-house database provided correct identification for all C. neoformans and C. gattii genotypes; however, due to the intergenotypic mass spectral similarities, a careful postanalytic evaluation is necessary to provide correct genotype identification.

scholarly journals Drug Resistance-Associated Mutations in ERG11 of Multidrug-Resistant Candida auris in a Tertiary Care Hospital of Eastern Saudi Arabia

2020 ◽  
Vol 7 (1) ◽  
pp. 18
Author(s):  
Reem AlJindan ◽  
Doaa M. AlEraky ◽  
Nehal Mahmoud ◽  
Baha Abdalhamid ◽  
Mashael Almustafa ◽  
...  
Keyword(s):  
Drug Resistance ◽  
18S Rrna ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Candida Auris ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Candida auris is an emerging multi-drug resistant pathogen with high mortality rate; nosocomial infections have been reported worldwide, causing a major challenge for clinicians and microbiological laboratories. The study aims to describe new cases of C. auris and detect drug resistance-associated mutations of C. auris by the sequencing of ERG11 and FKS1 genes. A total of six specimens were collected from blood, urine, ear swab, and groin screening samples. Isolates were incubated for 48 h on Sabouraud Dextrose agar (SDA) at 42 °C, then confirmed by MALDI-TOF MS. Furthermore, antifungal susceptibility testing was performed using the Vitek 2 system to detect Minimum Inhibitory Concentrations (MICs) of six antifungals. Sequences of 18S rRNA gene and ITS regions from isolates and phylogenetic analysis were performed. Gene sequencing was analysed to detect drug resistance-associated mutations by FKS1 and ERG11 genes sequencing. All C. auris isolates were confirmed by MALDI-TOF MS, and evolutionary analyses using sequences of 18S rRNA gene and ITS region. Antifungal susceptibility testing showed that all isolates were resistant to fluconazole. Sequencing of ERG11 and FKS1 genes from the isolates revealed the presence of two (F132Y and K143R) drug resistance-associated mutations in ERG11, however, FKS1 gene was devoid of mutations. The study sheds light on a public health threat of an emerging pathogen, and the hospital implemented strict contact screening and infection control precautions to prevent C. auris infection. Finally, there is a critical need to monitor the antifungal resistance in different geographical areas and implementation of efficient guidelines for treatment.

scholarly journals Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Clinically Relevant Filamentous Fungi

2016 ◽  
Vol 54 (8) ◽  
pp. 2068-2073 ◽  
Author(s):  
Allison R. McMullen ◽  
Meghan A. Wallace ◽  
David H. Pincus ◽  
Kathy Wilkey ◽  
Carey-Ann D. Burnham
Keyword(s):  
Filamentous Fungi ◽  
Species Level ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Tof Ms

Invasive fungal infections have a high rate of morbidity and mortality, and accurate identification is necessary to guide appropriate antifungal therapy. With the increasing incidence of invasive disease attributed to filamentous fungi, rapid and accurate species-level identification of these pathogens is necessary. Traditional methods for identification of filamentous fungi can be slow and may lack resolution. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid and accurate method for identification of bacteria and yeasts, but a paucity of data exists on the performance characteristics of this method for identification of filamentous fungi. The objective of our study was to evaluate the accuracy of the Vitek MS for mold identification. A total of 319 mold isolates representing 43 genera recovered from clinical specimens were evaluated. Of these isolates, 213 (66.8%) were correctly identified using the Vitek MS Knowledge Base, version 3.0 database. When a modified SARAMIS (Spectral Archive and Microbial Identification System) database was used to augment the version 3.0 Knowledge Base, 245 (76.8%) isolates were correctly identified. Unidentified isolates were subcultured for repeat testing; 71/319 (22.3%) remained unidentified. Of the unidentified isolates, 69 were not in the database. Only 3 (0.9%) isolates were misidentified by MALDI-TOF MS (includingAspergillus amoenus[n= 2] andAspergillus calidoustus[n= 1]) although 10 (3.1%) of the original phenotypic identifications were not correct. In addition, this methodology was able to accurately identify 133/144 (93.6%)Aspergillussp. isolates to the species level. MALDI-TOF MS has the potential to expedite mold identification, and misidentifications are rare.

scholarly journals Identification and Antifungal Susceptibility Profiles of Candida haemulonii Species Complex Clinical Isolates from a Multicenter Study in China

2016 ◽  
Vol 54 (11) ◽  
pp. 2676-2680 ◽  
Author(s):  
Xin Hou ◽  
Meng Xiao ◽  
Sharon C.-A. Chen ◽  
He Wang ◽  
Jing-Wei Cheng ◽  
...  
Keyword(s):  
Species Identification ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Its Sequencing ◽  
Species Classification ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Candida Haemulonii ◽  
Tof Ms

Candida haemulonii complex ( Candida haemulonii , Candida haemulonii var. vulnera , and Candida duobushaemulonii ) consists of emerging pathogens. Thirty-one isolates from 14 hospitals in China were studied for their species classification and antifungal susceptibilities. Performances of molecular (i.e., ribosomal DNA [rDNA] internal transcribed spacer [ITS] sequencing, D1/D2 sequencing, and ITS sequencer-based capillary gel electrophoresis [SCGE]) and phenotypic identification methods in species identification were compared. Twenty-six (83.9%) of 31 isolates were identified as C. haemulonii and 5 isolates were identified as C. duobushaemulonii by ITS sequencing as the reference method; results obtained by D1/D2 sequencing and ITS SCGE were concordant with those obtained by ITS sequencing for all (100%) of the isolates. All 31 isolates were identified as C. haemulonii by the Vitek matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system (bioMérieux, France), whereas the Bruker MS system (Bruker Daltoniks, Germany) correctly provided species identification for 77.4% and 100% of isolates using cutoff scores for species of ≥2.0 and ≥1.70, respectively. The Vitek 2 compact (bioMérieux) only identified 9 (29%) of 31 isolates. All isolates showed high MICs for amphotericin B (range, 2 to >8 μg/ml) and fluconazole (≥128 μg/ml) but low MICs (≤0.5 μg/ml) for the echinocandins. Our results reinforce the need for MALDI-TOF MS and/or molecular differentiation of species within the C. haemulonii complex. The multiresistant antifungal susceptibility profile of these isolates represents a challenge to therapy.

scholarly journals Resistance and Heteroresistance to Colistin in Pseudomonas aeruginosa Isolates from Wenzhou, China

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Jie Lin ◽  
Chunquan Xu ◽  
Renchi Fang ◽  
Jianming Cao ◽  
Xiucai Zhang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Population Analysis ◽  
Colistin Resistance ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Expression Levels ◽  
Maldi Tof ◽  
Broth Microdilution Method ◽  
Tof Ms

ABSTRACT The goal was to investigate the mechanisms of colistin resistance and heteroresistance in Pseudomonas aeruginosa clinical isolates. Colistin resistance was determined by the broth microdilution method. Colistin heteroresistance was evaluated by population analysis profiling. Time-kill assays were also conducted. PCR sequencing was performed to detect the resistance genes among (hetero)resistant isolates, and quantitative real-time PCR assays were performed to determine their expression levels. Pulsed-field gel electrophoresis and multilocus sequence typing were performed. Lipid A characteristics were determined via matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS). Two resistant isolates and 9 heteroresistant isolates were selected in this study. Substitutions in PmrB were detected in 2 resistant isolates. Among heteroresistant isolates, 8 of 9 heteroresistant isolates had nonsynonymous PmrB substitutions, and 2 isolates, including 1 with a PmrB substitution, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were upregulated in PmrB- or PhoQ-substituted isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of the pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-l-arabinose (l-Ara4N) moieties in lipid A profiles in (hetero)resistant isolates. In conclusion, both colistin resistance and heteroresistance in P. aeruginosa in this study mainly involved alterations of the PmrAB regulatory system. There were strong associations between mutations in specific genetic loci for lipid A synthesis and regulation of modifications to lipid A. The transition of colistin heteroresistance to resistance should be addressed in future clinical surveillance.

Sign in / Sign up

Export Citation Format

Share Document