MALDI-TOF MS for the Diagnosis of Infectious Diseases

Patel, Robin

doi:10.1373/clinchem.2014.221770

Cited by 415 publications

(308 citation statements)

References 79 publications

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“…Diagnoses of clinical brucellosis are made initially using serological tests and are confirmed by isolation of the agent (6,7). The recent introduction of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of bacteria and yeasts (8,9). However, the procedures recommended by the manufacturers for non-biosafety level 3 (BSL3) organisms are not adequate for the manipulation of Brucella strains, which are classified as BSL3 (potential bioterrorism pathogens) and represent potential health hazards for laboratory workers (1,10).…”

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confidence: 99%

A Simple and Safe Protocol for Preparing Brucella Samples for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

et al. 2016

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dWe describe a simple protocol to inactivate the biosafety level 3 (BSL3) pathogens Brucella prior to their analysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. This method is also effective for several other bacterial pathogens and allows storage, and eventually shipping, of inactivated samples; therefore, it might be routinely applied to unidentified bacteria, for the safety of laboratory workers. Brucellosis is a zoonosis caused by bacteria of the genus Brucella, which are transmitted to humans through direct contact, ingestion of contaminated animal products, or aerosolization (1, 2). Brucellosis is endemic in several regions of the world, with more than 500,000 new cases each year (2-5). To date, 10 recognized species of Brucella have been described, with the most pathogenic for humans being Brucella melitensis (2). Diagnoses of clinical brucellosis are made initially using serological tests and are confirmed by isolation of the agent (6, 7). The recent introduction of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of bacteria and yeasts (8, 9). However, the procedures recommended by the manufacturers for non-biosafety level 3 (BSL3) organisms are not adequate for the manipulation of Brucella strains, which are classified as BSL3 (potential bioterrorism pathogens) and represent potential health hazards for laboratory workers (1, 10). Any inactivation procedure must allow safe sample handling outside the BSL3 environment and must avoid destruction of the biomarkers used for identification. Therefore, we developed a simple, safe, and efficient sample preparation method for Brucella isolates that is compatible with their analysis by the current MALDI-TOF MS platforms.Solvent inactivation of Brucella. We first applied the direct transfer procedure recommended by the manufacturer to a panel of Brucella strains, working in class II microbiological safety cabinets in a BSL3 laboratory (Table 1). The target plate (Vitek MS DS slide; bioMérieux) was inoculated by picking a portion of a colony from a plate with a 1-l disposable loop (Sarsted), and the deposit was overlaid with 1 l of ␣-cyano-4-hydroxycinnamic acid (CHCA) matrix solution (saturated solution of CHCA in a solvent mixture composed of 33% acetonitrile, 33% absolute ethanol, 3% trifluoroacetic acid, and 31% water) and then air dried for 2 min at room temperature. The dried material was recovered with a sterile swab and spread on culture plates, which were then incubated for up to 3 weeks under the optimal growth conditions for the corresponding bacteria indicated in Table 1. Viable bacteria were recovered for most strains, showing that this protocol does not kill all Brucella strains, possibly because the bacterial deposit was not completely covered with the matrix solution. This risk is not acceptable for BSL3 pathogens. To overcome this problem, different liquid-phase inactivation protocols were tested in 1.5-ml Eppendorf tubes (see F...

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A Simple and Safe Protocol for Preparing Brucella Samples for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

et al. 2016

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“…Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a rapid, accurate, sensitive, and cost-effective method that offers an adequate alternative to genome-based approaches and that has been widely used for identification and typing of microorganisms in a clinical routine setup (12)(13)(14)(15)(16)(17)(18)(19), as well as for HPB (20)(21)(22)(23)(24)(25)(26)(27). This method does not depend on exclusive consumables and has revealed high levels of reproducibility in both intralaboratory and interlaboratory studies (28,29).…”

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Identification of Highly Pathogenic Microorganisms by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: Results of an Interlaboratory Ring Trial

et al. 2015

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mIn the case of a release of highly pathogenic bacteria (HPB), there is an urgent need for rapid, accurate, and reliable diagnostics. MALDI-TOF mass spectrometry is a rapid, accurate, and relatively inexpensive technique that is becoming increasingly important in microbiological diagnostics to complement classical microbiology, PCR, and genotyping of HPB. In the present study, the results of a joint exercise with 11 partner institutions from nine European countries are presented. In this exercise, 10 distinct microbial samples, among them five HPB, Bacillus anthracis, Brucella canis, Burkholderia mallei, Burkholderia pseudomallei, and Yersinia pestis, were characterized under blinded conditions. Microbial strains were inactivated by high-dose gamma irradiation before shipment. Preparatory investigations ensured that this type of inactivation induced only subtle spectral changes with negligible influence on the quality of the diagnosis. Furthermore, pilot tests on nonpathogenic strains were systematically conducted to ensure the suitability of sample preparation and to optimize and standardize the workflow for microbial identification. The analysis of the microbial mass spectra was carried out by the individual laboratories on the basis of spectral libraries available on site. All mass spectra were also tested against an in-house HPB library at the Robert Koch Institute (RKI). The averaged identification accuracy was 77% in the first case and improved to >93% when the spectral diagnoses were obtained on the basis of the RKI library. The compilation of complete and comprehensive databases with spectra from a broad strain collection is therefore considered of paramount importance for accurate microbial identification. Highly pathogenic bacteria (HPB) are risk group 3 bacteria, which are defined as biological agents that can cause severe human disease and present a serious hazard to health care workers. This may present a risk of spreading to the community, but there is usually effective prophylaxis or treatment available (1). To this group belong bacteria such as Bacillus anthracis, Francisella tularensis subsp. tularensis (type A), Yersinia pestis, species of the Brucella melitensis group, Burkholderia mallei, and Burkholderia pseudomallei. HPB have the potential to be used in bioterrorist attacks (2, 3). The Centers for Disease Control and Prevention (CDC, Atlanta, GA) have classified B. anthracis, F. tularensis, and Y. pestis as category A and Brucella species, B. mallei, B. pseudomallei, and Coxiella burnetii as category B, comprising the main pathogens of concern for use in bioterrorist attacks (4). These pathogens may cause anthrax, tularemia, plague, brucellosis, glanders, melioidosis, and Q fever, respectively. In most parts of the world, the natural prevalence of these agents is low, even though some of these agents cause outbreaks in human and animal populations from time to time (5-8). The intentional release of these agents, however, can result in severe public health consequences, as was shown in the U...

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“…For example, the Mayo Clinic has built a custom MALDI-TOF library that contains 1599 spectral images not covered by available databases (14 ). However, MALDI-TOF may not be the best technology for all identifications because other technologies, like 16S rRNA gene sequencing, may be better at rapidly identifying tiny or mucoid colonies (14 ).…”

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confidence: 99%

“…The commercialization of MALDI-TOF continues for clinical microbiology and systems consisting of the MS, software, and databases of microorganisms by some manufacturers (bioMerieux Inc. and Bruker Daltonics Inc.) have been FDA cleared. Although the FDAcleared list of organisms is not exhaustive and is primarily limited to gram-negative and gram-positive bacteria and yeast, research use-only libraries are also available (14 ). Effective Use of MS in the Clinical Lab…”

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Effective Use of Mass Spectrometry in the Clinical Laboratory

2016

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BACKGROUND:Historically the success of mass spectrometry in the clinical laboratory has focused on drugs of abuse confirmations, newborn screening, and steroid analysis. Clinical applications of mass spectrometry continue to expand, and mass spectrometry is now being used in almost all areas of laboratory medicine.CONTENT: A brief background of the evolution of mass spectrometry in the clinical laboratory is provided with a discussion of future applications. Prominent examples of mass spectrometry are covered to illustrate how it has improved the practice of medicine and enabled physicians to provide better patient care. With increasing economic pressures and decreasing laboratory test reimbursement, mass spectrometry testing has been shown to provide cost-effective solutions. In addition to pointing out the numerous benefits, the challenges of implementing mass spectrometry in the clinical laboratory are also covered.

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MALDI-TOF MS for the Diagnosis of Infectious Diseases

Cited by 415 publications

References 79 publications

A Simple and Safe Protocol for Preparing Brucella Samples for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

A Simple and Safe Protocol for Preparing Brucella Samples for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Analysis

Identification of Highly Pathogenic Microorganisms by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: Results of an Interlaboratory Ring Trial

Effective Use of Mass Spectrometry in the Clinical Laboratory

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