Multicenter validation of the VITEK MS v2.0 MALDI-TOF mass spectrometry system for the identification of fastidious gram-negative bacteria

Branda, John A.; Rychert, Jenna; Burnham, Carey‐Ann D.; Bythrow, Maureen; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra; Sercia, Linda; Westblade, Lars F.; Ferraro, Mary Jane

doi:10.1016/j.diagmicrobio.2013.08.013

Cited by 39 publications

(14 citation statements)

References 15 publications

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“…It is possible that use-dependent wear of integral instrument parts (e.g., lasers and turbo pumps) over time may not have significant consequences for routine bacterial and yeast identification, where many redundant spectral features are calculated into the overall identification algorithm. Reproducibility of MALDI-TOF MS for bacterial and yeast identification has been well demonstrated (17)(18)(19), leading to recent FDA approval of bacterial and yeast databases for the Bruker BioTyper and Vitek MS (bioMérieux, Durham, NC). In our case, declining instrument performance was not obvious from our routine bacterial runs; rather, instrument compromise was suspected when identification scores from our routine clinical mold and mycobacterial runs decreased over time.…”

Section: Discussionmentioning

confidence: 99%

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids

et al. 2016

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Rapid detection of bla KPC -containing organisms can significantly impact infection control and clinical practices, as well as therapeutic choices. Current molecular and phenotypic methods to detect these organisms, however, require additional testing beyond routine organism identification. In this study, we evaluated the clinical performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to detect pKpQIL_p019 (p019)-an ϳ11,109-Da protein associated with certain bla KPC -containing plasmids that was previously shown to successfully track a clonal outbreak of bla KPC -pKpQILKlebsiella pneumoniae in a proof-of-principle study (A. . PCR for the p019 gene was used as the reference method. Here, blind analysis of 140 characterized Enterobacteriaceae isolates using two protein extraction methods (plate extraction and tube extraction) and two peak detection methods (manual and automated) showed sensitivities and specificities ranging from 96% to 100% and from 95% to 100%, respectively (2,520 spectra analyzed). Feasible laboratory implementation methods (plate extraction and automated analysis) demonstrated 96% sensitivity and 99% specificity. All p019-positive isolates (n ‫؍‬ 26) contained bla KPC and were carbapenem resistant. Retrospective analysis of an additional 720 clinical Enterobacteriaceae spectra found an ϳ11,109-Da signal in nine spectra (1.3%), including seven from p019-containing, carbapenem-resistant isolates (positive predictive value [PPV], 78%). Instrument tuning had a significant effect on assay sensitivity, highlighting important factors that must be considered as MALDI-TOF MS moves into applications beyond microbial identification. Using a large blind clinical data set, we have shown that spectra acquired for routine organism identification can also be analyzed automatically in real time at high throughput, at no additional expense to the laboratory, to enable rapid detection of potentially bla KPC -containing carbapenemresistant isolates, providing early and clinically actionable results. The spread of carbapenemase-producing organisms represents an urgent global public health threat in an era of increased international travel and limited effective antimicrobial options. The genes encoding carbapenemases are commonly carried on plasmids, and it has been hypothesized that an important factor contributing to their spread is the diversity of the plasmid contexts in which they are found. In particular, the bla KPC gene encoding the Klebsiella pneumoniae carbapenemase (KPC) has been identified in a variety of plasmid backbones in association with a mobile Tn4401 transposable element. This association may have contributed to the global dissemination of the bla KPC gene in a variety of genera and species of bacteria (1). Rapid methods to detect bla KPC -carrying plasmids in the clinical microbiology laboratory would be of great clinical and epidemiologic value. Various techniques such as the Carba NP test (2), modified Hodge test (3), and molecular assays (4...

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Section: Discussionmentioning

confidence: 99%

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids

et al. 2016

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“…These studies showed 88.7% (27) and 96% correct identification rates with a score of Ͼ1.7 (21), compared to 97.4% (29) and 97.9% (30) with a score of Ͼ1.8. The Bruker MALDI Biotyper system did not generate erroneous fungal identifications (10,31).…”

Section: Discussionmentioning

confidence: 99%

Interlaboratory Comparison of Sample Preparation Methods, Database Expansions, and Cutoff Values for Identification of Yeasts by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Using a Yeast Test Panel

et al. 2014

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An interlaboratory study using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to determine the identification of clinically important yeasts (n ‫؍‬ 35) was performed at 11 clinical centers, one company, and one reference center using the Bruker Daltonics MALDI Biotyper system. The optimal cutoff for the MALDI-TOF MS score was investigated using receiver operating characteristic (ROC) curve analyses. The percentages of correct identifications were compared for different sample preparation methods and different databases.

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“…Recent studies have evaluated the identification of fastidious GNR using the Vitek MS system (bioMérieux, Marcy l'Etoile, France) and show reliable identification of HACEK organisms and other fastidious Gram-negative bacteria (31,32). The aim of this study was to evaluate the capability of the MALDI Biotyper system (Bruker Daltonics) to correctly identify fastidious GNR.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the Bruker MALDI Biotyper for Identification of Fastidious Gram-Negative Rods

et al. 2016

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Matrix-assisted laser desorption ionization؊time of flight mass spectrometry (MALDI-TOF MS) has entered clinical laboratories, facilitating identification of bacteria. Here, we evaluated the MALDI Biotyper (Bruker Daltonics) for the identification of fastidious Gram-negative rods (GNR). Three sample preparation methods, direct colony transfer, direct transfer plus on-target formic acid preparation, and ethanol-formic acid extraction, were analyzed for 151 clinical isolates. Direct colony transfer applied with the manufacturer's interpretation criteria resulted in overall species and genus identification rates of 43.0% and 32.5%, respectively; 23.2% of the isolates were not identified, and two misidentifications (1.3%) were observed. The species identification rates increased to 46.4% and 53.7% for direct transfer plus formic acid preparation and ethanol-formic acid extraction, respectively. In addition, we evaluated score value cutoff alterations. The identification rates hardly increased by reducing the genus cutoff, while reducing the 2.0 species cutoff to 1.9 and to 1.8 increased the identification rates to up to 66.2% without increasing the rate of misidentifications. This study shows that fastidious GNR can reliably be identified using the MALDI Biotyper. However, the identification rates do not reach those of nonfastidious GNR such as the Enterobacteriaceae. In addition, two approaches optimizing the identification of fastidious GNR by the MALDI Biotyper were demonstrated: formic acid-based ontarget sample treatment and reductions in cutoff scores to increase the species identification rates. Fastidious Gram-negative rods (GNR) are slow-growing bacteria that belong to different genera, such as Neisseria, Pasteurella, and the HACEK organisms (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella). Many of these species are commensal organisms of the human or animal oral cavity. They are isolated from wound infections, e.g., after a human or animal bite, but are also associated with endocarditis, septicemia, and abscesses, particularly in immunocompromised and elderly patients (1-4).Traditionally, identification of fastidious GNR in diagnostic laboratories is based on morphological and biochemical criteria. Identification is particularly challenging and time-consuming as these bacteria usually do not grow on standard media and require supplemental nutrients and/or a CO 2 -enriched atmosphere for growth (1-3). 16S rRNA gene sequencing is widely used in addition to conventional identification methods (5-7). Matrix-assisted laser desorption ionizationϪtime of flight mass spectrometry (MALDI-TOF MS) has been suggested as an alternative to molecular methods for the identification of fastidious GNR and other bacteria that are difficult to culture (8-10).Numerous studies have compared MALDI-TOF MS-based bacterial identification with molecular or biochemical identification methods (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Most of these studies included only limited numbers of fastidious GNR ...

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Multicenter validation of the VITEK MS v2.0 MALDI-TOF mass spectrometry system for the identification of fastidious gram-negative bacteria

Cited by 39 publications

References 15 publications

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids

Interlaboratory Comparison of Sample Preparation Methods, Database Expansions, and Cutoff Values for Identification of Yeasts by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Using a Yeast Test Panel

Evaluation of the Bruker MALDI Biotyper for Identification of Fastidious Gram-Negative Rods

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Multicenter validation of the VITEK MS v2.0 MALDI-TOF mass spectrometry system for the identification of fastidious gram-negative bacteria

Cited by 39 publications

References 15 publications

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla KPC -Containing Plasmids

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla KPC -Containing Plasmids

Interlaboratory Comparison of Sample Preparation Methods, Database Expansions, and Cutoff Values for Identification of Yeasts by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Using a Yeast Test Panel

Evaluation of the Bruker MALDI Biotyper for Identification of Fastidious Gram-Negative Rods

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Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids

Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain bla _KPC -Containing Plasmids