scholarly journals Evaluation of the Vitek MS v3.0 Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification ofMycobacteriumandNocardiaSpecies

2018 ◽  
Vol 56 (6) ◽  
pp. e00237-18 ◽  
Author(s):  
Barbara A. Body ◽  
Melodie A. Beard ◽  
E. Susan Slechta ◽  
Kimberly E. Hanson ◽  
Adam P. Barker ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Species Level ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Repeat Testing ◽  
Mass Spectrometry System ◽  
Vitek Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTThis multicenter study was designed to assess the accuracy and reproducibility of the Vitek MS v3.0 matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry system for identification ofMycobacteriumandNocardiaspecies compared to DNA sequencing. A total of 963 clinical isolates representing 51 taxa were evaluated. In all, 663 isolates were correctly identified to the species level (69%), with another 231 (24%) correctly identified to the complex or group level. Fifty-five isolates (6%) could not be identified despite repeat testing. All of the tuberculous mycobacteria (45/45; 100%) and most of the nontuberculous mycobacteria (569/606; 94%) were correctly identified at least to the group or complex level. However, not all species or subspecies within theM. tuberculosis,M. abscessus, andM. aviumcomplexes and within theM. fortuitumandM. mucogenicumgroups could be differentiated. Among the 312Nocardiaisolates tested, 236 (76%) were correctly identified to the species level, with an additional 44 (14%) correctly identified to the complex level. Species within theN. novaandN. transvalensiscomplexes could not always be differentiated. Eleven percent of the isolates (103/963) underwent repeat testing in order to get a final result. Identification of a representative set ofMycobacteriumandNocardiaspecies was highly reproducible, with 297 of 300 (99%) replicates correctly identified using multiple kit lots, instruments, analysts, and sites. These findings demonstrate that the system is robust and has utility for the routine identification of mycobacteria andNocardiain clinical practice.

scholarly journals Comparison of the Vitek MS and Bruker Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Systems for Identification of Rhodococcus equi and Dietzia spp.

2017 ◽  
Vol 55 (7) ◽  
pp. 2255-2260 ◽  
Author(s):  
Carlos Ruiz de Alegría Puig ◽  
Lilian Pilares ◽  
Francesc Marco ◽  
Jordi Vila ◽  
Luis Martínez-Martínez ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Species Level ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTRhodococcus equicauses pyogranulomatous pneumonia in domesticated animals and immunocompromised humans.Dietziaspp. are environmental bacteria that have rarely been associated with human infections.R. equiandDietziaspp. are closely related actinomycetes. Phenotypic discrimination betweenR. equiandDietziaon the basis of their Gram stain morphology and colony appearance is problematic. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a fast, reliable, and cost-effective method for identification of a wide variety of microorganisms. We have evaluated the performance of Bruker Biotyper versus that of Vitek MS for identification of a collection of 154 isolates identified at the source asR. equithat includes isolates belonging to the genusDietzia. PCR amplification of thechoEgene, encoding a cholesterol oxidase, and 16S rRNA sequencing were considered the reference methods forR. equiidentification. Biotyper identified 131 (85.1%) of the 154 isolates at the species level, and this figure increased to 152 (98.7%) when the species cutoff was reduced from a score of ≥2.000 to ≥1.750. Vitek MS correctly identified at the species level 130 (84.4%) isolates as long as bacteria were extracted with ethanol but only 35 (22.7%) isolates when samples were prepared by direct extraction from colonies. The two systems allowed differentiation betweenR. equiandDietziaspp., but identification of allDietziasp. isolates at the species level needed sequencing of the 16S rRNA gene.

scholarly journals Evaluation of Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry for Identification of Mycobacterium abscessus Subspecies According to Whole-Genome Sequencing

2016 ◽  
Vol 54 (12) ◽  
pp. 2982-2989 ◽  
Author(s):  
Liulin Luo ◽  
Weijia Liu ◽  
Bing Li ◽  
Mengling Li ◽  
Dongdong Huang ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Mycobacterium Abscessus ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

This study was undertaken to evaluate the utility of matrix-assisted laser desorption ionization–time of flight mass spectrometry with the Vitek MS Plus system for identifying Mycobacterium abscessus subspecies in order to facilitate more rapid and appropriate therapy. A total of 175 clinical M. abscessus strains were identified by whole-genome sequencing analysis: 139 Mycobacterium abscessus subsp. abscessus and 36 Mycobacterium abscessus subsp. massiliense . The research-use-only (RUO) Saramis Knowledge Base database v.4.12 was modified accordingly by adding 40 M. abscessus subsp. abscessus and 19 M. abscessus subsp. massiliense reference spectra to construct subspecies SuperSpectra. A blind test, used to validate the remaining 116 isolates, yielded 99.1% ( n = 115) reliability and only 0.9% ( n = 1) error for subspecies identification. Among the two subspecies SuperSpectra, two specific peaks were found for M. abscessus subsp. abscessus and four specific peaks were found for M. abscessus subsp. massiliense . Our study is the first to report differential peaks 3,354.4 m / z and 6,711.1 m / z , which were specific for M. abscessus subsp. massiliense . Our research demonstrates the capacity of the Vitek MS RUO Saramis Knowledge Base database to identify M. abscessus at the subspecies level. Moreover, it validates the potential ease and accuracy with which it can be incorporated into the IVD system for the identification of M. abscessus subspecies.

scholarly journals A Comprehensive Evaluation of the Bruker Biotyper MS and Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Systems for Identification of Yeasts, Part of the National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) Study, 2012 to 2013

2016 ◽  
Vol 54 (5) ◽  
pp. 1376-1380 ◽  
Author(s):  
He Wang ◽  
Yan-Yan Fan ◽  
Timothy Kudinha ◽  
Zhi-Peng Xu ◽  
Meng Xiao ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Among the 2,683 yeast isolates representing 41 different species (25CandidaandCandida-related species and 16 non-Candidayeast species) collected in the National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) program (2012 to 2013), the Bruker Biotyper MS matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system exhibited significantly higher accuracy rates than the Vitek MS system for identification of all yeast isolates (98.8% versus 95.4%,P<0.001 by Pearson's chi-square test) and for allCandidaandCandida-related species isolates (99.4% versus 95.5%,P< 0.001).

scholarly journals Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Combined Species Identification and Drug Sensitivity Testing in Mycobacteria

2016 ◽  
Vol 55 (2) ◽  
pp. 624-634 ◽  
Author(s):  
Pieter-Jan Ceyssens ◽  
Karine Soetaert ◽  
Markus Timke ◽  
An Van den Bossche ◽  
Katrin Sparbier ◽  
...  
Keyword(s):  
Species Identification ◽  
Laser Desorption ◽  
Drug Susceptibility ◽  
Species Level ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTSpecies identification and drug susceptibility testing (DST) of mycobacteria are important yet complex processes traditionally reserved for reference laboratories. Recent technical improvements in matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has started to facilitate routine mycobacterial identifications in clinical laboratories. In this paper, we investigate the possibility of performing phenotypic MALDI-based DST in mycobacteriology using the recently described MALDI Biotyper antibiotic susceptibility test rapid assay (MBT-ASTRA). We randomly selected 72 clinicalMycobacterium tuberculosisand nontuberculous mycobacterial (NTM) strains, subjected them to MBT-ASTRA methodology, and compared its results to current gold-standard methods. Drug susceptibility was tested for rifampin, isoniazid, linezolid, and ethambutol (M. tuberculosis,n= 39), and clarithromycin and rifabutin (NTM,n= 33). Combined species identification was performed using the Biotyper Mycobacteria Library 4.0.Mycobacterium-specific MBT-ASTRA parameters were derived (calculation window,m/z5,000 to 13,000, area under the curve [AUC] of >0.015, relative growth [RG] of <0.5; see the text for details). Using these settings, MBT-ASTRA analyses returned 175/177M. tuberculosisand 65/66 NTM drug resistance profiles which corresponded to standard testing results. Turnaround times were not significantly different inM. tuberculosistesting, but the MBT-ASTRA method delivered on average a week faster than routine DST in NTM. Databases searches returned 90.4% correct species-level identifications, which increased to 98.6% when score thresholds were lowered to 1.65. In conclusion, the MBT-ASTRA technology holds promise to facilitate and fasten mycobacterial DST and to combine it directly with high-confidence species-level identifications. Given the ease of interpretation, its application in NTM typing might be the first in finding its way to current diagnostic workflows. However, further validations and automation are required before routine implementation can be envisioned.

scholarly journals Performance of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identifying Clinical Malassezia Isolates

2016 ◽  
Vol 55 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Julie Denis ◽  
Marie Machouart ◽  
Florent Morio ◽  
Marcela Sabou ◽  
Catherine Kauffmann-LaCroix ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT The genus Malassezia comprises commensal yeasts on human skin. These yeasts are involved in superficial infections but are also isolated in deeper infections, such as fungemia, particularly in certain at-risk patients, such as neonates or patients with parenteral nutrition catheters. Very little is known about Malassezia epidemiology and virulence. This is due mainly to the difficulty of distinguishing species. Currently, species identification is based on morphological and biochemical characteristics. Only molecular biology techniques identify species with certainty, but they are time-consuming and expensive. The aim of this study was to develop and evaluate a matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) database for identifying Malassezia species by mass spectrometry. Eighty-five Malassezia isolates from patients in three French university hospitals were investigated. Each strain was identified by internal transcribed spacer sequencing. Forty-five strains of the six species Malassezia furfur , M. sympodialis , M. slooffiae , M. globosa , M. restricta , and M. pachydermatis allowed the creation of a MALDI-TOF database. Forty other strains were used to test this database. All strains were identified by our Malassezia database with log scores of >2.0, according to the manufacturer's criteria. Repeatability and reproducibility tests showed a coefficient of variation of the log score values of <10%. In conclusion, our new Malassezia database allows easy, fast, and reliable identification of Malassezia species. Implementation of this database will contribute to a better, more rapid identification of Malassezia species and will be helpful in gaining a better understanding of their epidemiology.

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