Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Nontuberculous Mycobacteria from Clinical Isolates

Rodríguez‐Sánchez, Belén; Ruiz‐Serrano, María Jesús; Marı́n, Mercedes; Roa, Paula López; Rodríguez‐Créixems, Marta; Bouza, Emilio

doi:10.1128/jcm.01380-15

Cited by 39 publications

(23 citation statements)

References 15 publications

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“…Identification of mycobacteria has not reached an optimal level of routine testing yet and published studies showed discrepant performances, depending on spectrometer, extraction method, algorithm, library, media, and biomass used for the assays (15)(16)(17)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32). In this study, we compared two distinct databases of Vitek-MS, the Saramis v4.12 open database and the new IVD v3.0 closed database.…”

Section: Discussionmentioning

confidence: 99%

“…It was initially evaluated with mycobacterial intact cells (9)(10)(11)(12), but several investigators worked on improving inactivation and protein extraction (13)(14)(15)(16)(17)(18)(19)(20). Most published studies assessed the performance of MALDI-TOF BioTyper (Bruker Daltonics, Bremen, Germany) (15,17,(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Few of them evaluated Vitek MS (bioMérieux, Marcy l'Etoile, France) (16,17,20,24,25,32).…”

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confidence: 99%

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Comparison of Saramis 4.12 and IVD 3.0 Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Mycobacteria from Solid and Liquid Culture Media

et al. 2017

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During the last decade, many investigators have studied matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identification of mycobacteria. Diverse and contradictory results indicated that optimal level for routine testing has not been reached yet. This work aimed to assess Vitek MS through two distinct versions, Saramis v4.12 RUO and the IVD v3.0, under conditions close to routine laboratory practice. Overall, 111 mycobacterial isolates were subjected to protein extraction and same spectra were matched against both databases. The IVD v3.0 database proved to be superior to Saramis v4.12 and its identification rates remarkably increased, from 67% to 94% for isolates grown on Middlebrook 7H10 solid medium and from 62% to 91% for isolates grown on mycobacterial growth indicator tube (MGIT) liquid medium. With this new version, IVD v3.0, MALDI-TOF MS might be integrated into routine clinical diagnostics, although molecular techniques remain mandatory in some cases.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Comparison of Saramis 4.12 and IVD 3.0 Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Mycobacteria from Solid and Liquid Culture Media

et al. 2017

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“…Differences were mainly due to the increased number of M. avium, M. gordonae, M. kansasii, and M. xenopi isolates correctly identified at a high-confidence level. Previous studies have already shown that the identification of M. avium and M. gordonae with a log(score) value of Ն1.8 was sometimes difficult to reach using older databases (3)(4)(5). However, the In conclusion, the use of the improved Mycobacteria Library v3.0 has increased the number of NTM isolates that attain a highconfidence identification level.…”

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confidence: 94%

“…The Mycobacteria Library database (Bruker Daltonik GmbH, Bremen, Germany) available so far (v2.0) provided low scores, particularly for NTM belonging to the slow-growing groups (3)(4)(5). In the present study, we assessed the power of a new database to identify NTM (i.e., Mycobacteria Library v3.0) using 109 isolates from 26 NTM species (Table 1) and compared the identification scores of version v2.0 and version v3.0.…”

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confidence: 99%

Evaluation of MALDI Biotyper Mycobacteria Library v3.0 for Identification of Nontuberculous Mycobacteria

et al. 2016

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e Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has demonstrated its ability to promptly identify nontuberculous mycobacteria using the Mycobacteria Library v2.0. However, some species are particularly difficult to identify reliably using this database, providing a low log(score). In this study, the identification power of an updated Mycobacteria Library (v3.0) has been evaluated. Overall, 109 NTM isolates were analyzed with both databases. The v3.0 database allowed a high-level confidence in the identification [log(score) value, >1.8] of 91.7% of the isolates versus 83.5% with the v2.0 version (P < 0.01). Rapid identification of nontuberculous mycobacteria (NTM) with matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS) has outperformed molecular techniques, such as GenoType (Hain Lifescience GmbH, Nehren, Germany), and provides accurate identification that correlates well with 16S rRNA gene sequencing when applied to the most common species of NTM (1-3). The Mycobacteria Library database (Bruker Daltonik GmbH, Bremen, Germany) available so far (v2.0) provided low scores, particularly for NTM belonging to the slow-growing groups (3-5). In the present study, we assessed the power of a new database to identify NTM (i.e., Mycobacteria Library v3.0) using 109 isolates from 26 NTM species (Table 1) and compared the identification scores of version v2.0 and version v3.0.Ninety-nine nonselected NTM isolates from clinical samples and 10 reference strains (Table 1) were collected in the clinical microbiology laboratory from the Hospital Gregorio Marañón (Madrid, Spain) between January 2011 and May 2015. These isolates were routinely identified by 16S rRNA hsp65 sequencing and, in parallel, by MALDI-TOF MS using a Microflex LT benchtop mass spectrometer (Bruker Daltonik) and the Mycobacteria Library v2.0, containing 313 Mycobacterium isolates from 131 species (Bruker Daltonik) (4). Sample preparation was described elsewhere (6). Briefly, colonies of NTM isolates grown on Lowenstein-Jensen medium were harvested into a 1.5-ml Eppendorf tube with 300 l of deionized water and inactivated for 30 min at 95°C under biosafety level 3 conditions. Then, they were centrifuged at maximal speed and subsequently resuspended in 300 l of water and 900 l of absolute ethanol and centrifuged again at 13,000 rpm. The supernatant was discarded, and the pellet was taken to biosafety level 2 conditions in order to disrupt the mycobacteria cell aggregates with silica bead vortexing and extract the bacterial proteins using formic acid and acetonitrile. In the end, 1 l of supernatant was placed onto a steel plate for MALDI-TOF MS analysis. Samples were analyzed in duplicates; the species identification, using the Mycobacteria Library v2.0, and the higher log(score) value result were recorded. For comparison reasons, all of the protein spectra from the 109 NTM isolates were reanalyzed using the new Mycobacteria Library v3.0, containing 853 references from 149 Mycob...

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“…Previous studies of the identification of mycobacteria by MALDI-TOF MS used laboratory strain collections, i.e., pure cultures from frozen stocks, or worked only from solid media (4,7,8). In that setting, MALDI-TOF MS performs much better, but that is not informative for clinical laboratories, where identification of primary cultures is required to guide diagnosis and treatment.…”

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confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Fails To Identify Nontuberculous Mycobacteria from Primary Cultures of Respiratory Samples

et al. 2016

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We have assessed matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification (Bruker) of nontuberculous mycobacteria from newly positive liquid cultures of respiratory samples. Twelve (22%) of 54 isolates were identified directly from liquid medium. After subculture and with manual laser operation, this rose to 49/54 isolates (91%). MALDI-TOF MS is less promising than previously suggested. N ontuberculous mycobacteria (NTM) are increasingly recognized as mostly opportunistic pathogens of humans. The most frequent disease manifestation is a chronic pulmonary infection (1). Since NTM are environmental microorganisms, their presence in pulmonary samples need not indicate disease per se. The clinical relevance of NTM isolation differs strongly by species (2). Hence, correct identification is of paramount importance (3).Identification of NTM is done mostly by using molecular tools. While accurate, these require a good laboratory infrastructure and trained personnel and are costly. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized identification in general bacteriology and has also been tried for NTM (3). Most studies of MALDI-TOF MS identification of NTM have applied it to pure cultures from strain collections (4) rather than new positive cultures from clinical samples from nonsterile sites.We assessed MALDI-TOF MS identification of NTM directly from new positive liquid cultures of respiratory samples in a mycobacterial disease reference clinic.Primary cultures of respiratory samples were performed with the Mycobacterium Growth Indicator Tube (MGIT) system (BD Bioscience, Erembodegem, Belgium), as well as on Löwenstein-Jensen slants, both at 37°C, after decontamination by the 1% Nacetyl-L-cysteine-sodium hydroxide method (3).All of the positive cultures that we obtained during the MarchApril 2014 and January-February 2015 periods that tested negative in the TBc-ID immunochromatography assay (BD Bioscience) were studied.We performed MALDI-TOF MS identification with the MALDI Biotyper (Bruker Daltonics, Bremen, Germany) platform. Protein extraction from liquid MGIT medium for MALDI-TOF MS analysis was performed by the manufacturer's MycoEx protocol. In short, we collected biomass by aspirating 1.2 ml of liquid medium from the bottom of the MGIT tube and transferring it to a reaction tube, which was then centrifuged for 2 min at 13,000 rpm (8,124 ϫ g; 43-mm rotor radius); the supernatant was pipetted off, the pellet was resuspended in 300 l of high-performance liquid chromatography grade water, and cells were then inactivated by boiling for 30 min. A 900-l volume of pure cold ethanol was then added, and the tube was vortexed and centrifuged for 2 min at 13,000 rpm. The supernatant was pipetted off. The last two steps were repeated once. The pellet was dried at room temperature before the addition of zirconium beads and 10 to 50 l of pure acetonitrile, depending on the pellet size. After 1 min of vortexing, we adde...

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Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Nontuberculous Mycobacteria from Clinical Isolates

Cited by 39 publications

References 15 publications

Comparison of Saramis 4.12 and IVD 3.0 Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Mycobacteria from Solid and Liquid Culture Media

Comparison of Saramis 4.12 and IVD 3.0 Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Mycobacteria from Solid and Liquid Culture Media

Evaluation of MALDI Biotyper Mycobacteria Library v3.0 for Identification of Nontuberculous Mycobacteria

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Fails To Identify Nontuberculous Mycobacteria from Primary Cultures of Respiratory Samples

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