scholarly journals Peaks of Promise and Peril: Screening for Antibiotic Resistance by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2015 ◽  
Vol 54 (1) ◽  
pp. 5-6 ◽  
Author(s):  
Neil W. Anderson
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Mass Spectrometry ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

An article in this issue of theJournal of Clinical Microbiology(J.-H. Youn, S. K. Drake, R. A. Weingarten, K. M. Frank, J. P. Dekker, and A. F. Lau, J Clin Microbiol 53:35–42, 2015,http://dx.doi.org/10.1128/JCM.01643-15) describes the use of matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry for the detection of organisms carrying ablaKPC-containing plasmid. This powerful and promising application highlights the challenges of using MALDI-TOF mass spectrometry for purposes other than organism identification.

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.

Can Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) Enhance Antimicrobial Stewardship Efforts in the Acute Care Setting?

2013 ◽  
Vol 34 (9) ◽  
pp. 990-995 ◽  
Author(s):  
Pranita D. Tamma ◽  
Kennard Tan ◽  
Veronique R. Nussenblatt ◽  
Alison E. Turnbull ◽  
Karen C. Carroll ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

We evaluated 222 hospitalized patients whose clinical isolates were tested using standard methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). MALDI-TOF could have reduced time to appropriate therapy for 28.8% and 44.6% patients based on the treating physician's choices and stewardship team recommendations, respectively. Clinicians should be aware of scenarios in which MALDI-TOF can optimize antibiotic therapy.

scholarly journals Efficient Detection of Carbapenemase Activity in Enterobacteriaceae by Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry in Less Than 30 Minutes

2015 ◽  
Vol 53 (7) ◽  
pp. 2163-2171 ◽  
Author(s):  
Camille Lasserre ◽  
Luc De Saint Martin ◽  
Gaelle Cuzon ◽  
Pierre Bogaerts ◽  
Estelle Lamar ◽  
...  
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

The recognition of carbapenemase-producingEnterobacteriaceae(CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity inEnterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.

scholarly journals Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry of Lipopeptide Biosurfactants in Whole Cells and Culture Filtrates of Bacillus subtilis C-1 Isolated from Petroleum Sludge

2002 ◽  
Vol 68 (12) ◽  
pp. 6210-6219 ◽  
Author(s):  
Joachim Vater ◽  
Bärbel Kablitz ◽  
Christopher Wilde ◽  
Peter Franke ◽  
Neena Mehta ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Mass Spectrometry ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Lipopeptide Biosurfactants ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT An innovative method was developed for rapid sensitive detection and efficient structural characterization of lipopeptide biosurfactants by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry by using whole microbial cells and crude culture filtrates as targets in combination with surface tension measurements. This was done for a bacterial strain that was isolated from petroleum sludge and efficiently produces biosurfactants. This organism was identified by using biochemical, physiological, and genetic parameters as a Bacillus subtilis strain, designated B. subtilis C-1. This assignment was supported by a mass spectrometric investigation of the secondary metabolite spectrum determined by whole-cell MALDI-TOF mass spectrometry, which revealed three lipopeptide complexes, the surfactins, the iturins, and the fengycins, which are well-known biosurfactants produced by B. subtilis strains. These compounds were structurally characterized by in situ structure analysis by using postsource decay MALDI-TOF mass spectrometry. The isoforms were separated by miniaturized high-resolution reversed-phase high-performance liquid chromatography for mass spectrometric characterization. Iturin compounds which contain unusual fatty acid components were detected.

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