Novel, Improved Sample Preparation for Rapid, Direct Identification from Positive Blood Cultures Using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

Schubert, Sören; Weinert, Kirsten; Wagner, Chris; Gunzl, Beatrix; Wieser, Andreas; Maier, Τ.; Kostrzewa, Markus

doi:10.1016/j.jmoldx.2011.07.004

Cited by 143 publications

(138 citation statements)

References 22 publications

(28 reference statements)

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“…Other rapid methods for detection of pathogens in positive blood cultures such as MALDI-TOF analysis perform better with Gram-negative than Gram-positive isolates; they show significant variability in performance, with percentages of isolates accurately detected and identified ranging from 37% to 86.3% depending on the protocol (16)(17)(18). Similar issues have been associated with DNA probe-based assays that target multiple pathogens, with discordant results ranging from 11% to 21% for Gram-positive cocci (22,23).…”

Section: Discussionmentioning

confidence: 92%

“…Other approaches included molecular amplification methods coupled with probebased detection (10,13,14). Matrix-associated laser desorption ionization-time of flight (MALDI-TOF) analysis for identification of bacterial isolates from positive blood cultures is another recent development (15)(16)(17)(18). Each methodology has limitations, for example, the inability to detect resistance markers (PNA-FISH and MALDI-TOF) or problems with detecting polymicrobial infections (MALDI-TOF) (16,17).…”

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confidence: 99%

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Evaluation of a Microarray-Based Assay for Rapid Identification of Gram-Positive Organisms and Resistance Markers in Positive Blood Cultures

et al. 2013

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Rapid identification of pathogens directly from positive blood cultures can play a major role in reducing patient mortality rates. We evaluated the performance of the Verigene Gram-Positive Blood Culture (BC-GP) assay (Nanosphere Inc., Northbrook, IL) for detection of commonly isolated Gram-positive organisms as well as associated resistance markers from positive blood cultures. Positive blood cultures (VersaTREK; Trek Diagnostic Systems, Independence, OH) from 203 patients with Gram-positive organism infections were analyzed using the BC-GP assay within 12 h for the detection of 12 different organisms, including staphylococci, streptococci, and enterococci, as well as for the presence of 3 resistance markers (mecA, vanA, and vanB). Results were compared to those of routine laboratory methods for identification and susceptibility testing. For identification of organisms and detection of resistance markers in 178 monomicrobial positive blood cultures, the BC-GP assay showed 94% and 97% concordance, respectively, with routine methods. After 25 polymicrobial cultures were included, the results showed 92% and 96% agreement for identification and resistance markers, respectively, for a total of 203 positive cultures. In 6/25 polymicrobial cultures, at least 1 isolate was not detected. Concordance levels for detection of major pathogens such Staphylococcus aureus (n ‫؍‬ 45) and enterococci (n ‫؍‬ 19) were 98% and 95%, respectively. Agreement levels for detection of resistance markers such as mecA and vanA/B were 92% and 100%, respectively. The BC-GP assay is capable of providing rapid identification of Gram-positive cocci as well as detection of resistance markers directly from positive blood cultures at least 24 to 48 h earlier than conventional methods.

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Section: Discussionmentioning

confidence: 92%

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Evaluation of a Microarray-Based Assay for Rapid Identification of Gram-Positive Organisms and Resistance Markers in Positive Blood Cultures

et al. 2013

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“…Especially, for positive blood cultures it is very important to quickly identify the microorganisms and to get information about possible resistances. MALDI-TOF MS provides quick identification (12,(15)(16)(17), and the MALDI-TOF MS-based resistance assay facilitates the rapid detection of ␤-lactamase-mediated resistance. Using the respective antibiotics/inhibitor combinations, differentiation and confirmation of the underlying ␤-lactamase also are possible.…”

Section: Discussionmentioning

confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Functional Assay for Rapid Detection of Resistance against β-Lactam Antibiotics

Schubert²,

et al. 2012

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Resistance against ␤-lactam antibiotics is a growing challenge for managing severe bacterial infections. The rapid and costefficient determination of ␤-lactam resistance is an important prerequisite for the choice of an adequate antibiotic therapy. ␤-Lactam resistance is based mainly on the expression/overexpression of ␤-lactamases, which destroy the central ␤-lactam ring of these drugs by hydrolysis. Hydrolysis corresponds to a mass shift of ؉18 Da, which can be easily detected by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Therefore, a MALDI-TOF MS-based assay was set up to investigate different enterobacteria for resistance against different ␤-lactam antibiotics: ampicillin, piperacillin, cefotaxime, ceftazidime, ertapenem, imipenem, and meropenem. ␤-Lactamases are enzymes that have a high turnover rate. Therefore, hydrolysis can be detected by MALDI-TOF MS already after a few hours of incubation of the bacteria to be tested with the given antibiotic. The comparison of the MS-derived data with the data from the routine procedure revealed identical classification of the bacteria according to sensitivity and resistance. The MALDI-TOF MS-based assay delivers the results on the same day. The approved routine procedures require at least an additional overnight incubation.

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“…Details on MALDI-TOF MS have been provided by Schubert et al, 29 where pathogens were identified from an agar plate. Recently, however, Sepsityper (Bruker, Billerica, MA, USA), a preparation method prior to MALDI-TOF MS, has been developed, allowing MALDI-TOF MS to be used directly on a positive blood culture bottles without the need for growing pathogens on an agar plate.…”

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Sepsis: the LightCycler SeptiFast Test MGRADE®, SepsiTest™ and IRIDICA BAC BSI assay for rapidly identifying bloodstream bacteria and fungi – a systematic review and economic evaluation

Stevenson

Pandor

James

et al. 2016

Health Technol Assess

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BackgroundSepsis can lead to multiple organ failure and death. Timely and appropriate treatment can reduce in-hospital mortality and morbidity.ObjectivesTo determine the clinical effectiveness and cost-effectiveness of three tests [LightCycler SeptiFast Test MGRADE®(Roche Diagnostics, Risch-Rotkreuz, Switzerland); SepsiTestTM(Molzym Molecular Diagnostics, Bremen, Germany); and the IRIDICA BAC BSI assay (Abbott Diagnostics, Lake Forest, IL, USA)] for the rapid identification of bloodstream bacteria and fungi in patients with suspected sepsis compared with standard practice (blood culture with or without matrix-absorbed laser desorption/ionisation time-of-flight mass spectrometry).Data sourcesThirteen electronic databases (including MEDLINE, EMBASE and The Cochrane Library) were searched from January 2006 to May 2015 and supplemented by hand-searching relevant articles.Review methodsA systematic review and meta-analysis of effectiveness studies were conducted. A review of published economic analyses was undertaken and a de novo health economic model was constructed. A decision tree was used to estimate the costs and quality-adjusted life-years (QALYs) associated with each test; all other parameters were estimated from published sources. The model was populated with evidence from the systematic review or individual studies, if this was considered more appropriate (base case 1). In a secondary analysis, estimates (based on experience and opinion) from seven clinicians regarding the benefits of earlier test results were sought (base case 2). A NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Scenario analyses were used to assess uncertainty.ResultsFor the review of diagnostic test accuracy, 62 studies of varying methodological quality were included. A meta-analysis of 54 studies comparing SeptiFast with blood culture found that SeptiFast had an estimated summary specificity of 0.86 [95% credible interval (CrI) 0.84 to 0.89] and sensitivity of 0.65 (95% CrI 0.60 to 0.71). Four studies comparing SepsiTest with blood culture found that SepsiTest had an estimated summary specificity of 0.86 (95% CrI 0.78 to 0.92) and sensitivity of 0.48 (95% CrI 0.21 to 0.74), and four studies comparing IRIDICA with blood culture found that IRIDICA had an estimated summary specificity of 0.84 (95% CrI 0.71 to 0.92) and sensitivity of 0.81 (95% CrI 0.69 to 0.90). Owing to the deficiencies in study quality for all interventions, diagnostic accuracy data should be treated with caution. No randomised clinical trial evidence was identified that indicated that any of the tests significantly improved key patient outcomes, such as mortality or duration in an intensive care unit or hospital. Base case 1 estimated that none of the three tests provided a benefit to patients compared with standard practice and thus all tests were dominated. In contrast, in base case 2 it was estimated that all cost per QALY-gained values were below £20,000; the IRIDICA BAC BSI assay had the highest estimated incremental net benefit, but results from base case 2 should be treated with caution as these are not evidence based.LimitationsRobust data to accurately assess the clinical effectiveness and cost-effectiveness of the interventions are currently unavailable.ConclusionsThe clinical effectiveness and cost-effectiveness of the interventions cannot be reliably determined with the current evidence base. Appropriate studies, which allow information from the tests to be implemented in clinical practice, are required.Study registrationThis study is registered as PROSPERO CRD42015016724.FundingThe National Institute for Health Research Health Technology Assessment programme.

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Novel, Improved Sample Preparation for Rapid, Direct Identification from Positive Blood Cultures Using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

Abstract: Matrix-assisted laser desorption ionization time-offlight mass spectrometry (MALDI-TOF MS) is widely

Cited by 143 publications

References 22 publications

Evaluation of a Microarray-Based Assay for Rapid Identification of Gram-Positive Organisms and Resistance Markers in Positive Blood Cultures

Evaluation of a Microarray-Based Assay for Rapid Identification of Gram-Positive Organisms and Resistance Markers in Positive Blood Cultures

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Functional Assay for Rapid Detection of Resistance against β-Lactam Antibiotics

Sepsis: the LightCycler SeptiFast Test MGRADE®, SepsiTest™ and IRIDICA BAC BSI assay for rapidly identifying bloodstream bacteria and fungi – a systematic review and economic evaluation

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