scholarly journals Effect of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS) Alone versus MALDI-TOF MS Combined with Real-Time Antimicrobial Stewardship Interventions on Time to Optimal Antimicrobial Therapy in Patients with Positive Blood Cultures

2017 ◽  
Vol 55 (5) ◽  
pp. 1437-1445 ◽  
Author(s):  
Maya Beganovic ◽  
Michael Costello ◽  
Sarah M. Wieczorkiewicz
Keyword(s):  
Real Time ◽  
Laser Desorption ◽  
Blood Cultures ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

ABSTRACT Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) decreases the time to organism identification and improves clinical and financial outcomes. The purpose of this study was to evaluate the impact of MALDI-TOF MS alone versus MALDI-TOF MS combined with real-time, pharmacist-driven, antimicrobial stewardship (AMS) intervention on patient outcomes. This single-center, pre-post, quasiexperimental study evaluated hospitalized patients with positive blood cultures identified via MALDI-TOF MS combined with prospective AMS intervention compared to a control cohort with MALDI-TOF MS identification without AMS intervention. AMS intervention included: real-time MALDI-TOF MS pharmacist notification and prospective AMS provider feedback. The primary outcome was the time to optimal therapy (TTOT). A total of 252 blood cultures, 126 in each group, were included in the final analysis. MALDI-TOF MS plus AMS intervention significantly reduced the overall TTOT (75.17 versus 43.06 h; P < 0.001), the Gram-positive contaminant TTOT (48.21 versus 11.75 h; P < 0.001), the Gram-negative infection (GNI) TTOT (71.83 versus 35.98 h; P < 0.001), and the overall hospital length of stay (LOS; 15.03 versus 9.02 days; P = 0.021). The TTOT for Gram-positive infection (GPI) was improved (64.04 versus 41.61 h; P = 0.082). For GPI, the hospital LOS (14.64 versus 10.31 days; P = 0.002) and length of antimicrobial therapy 24.30 versus 18.97 days; P = 0.018) were reduced. For GNI, the time to microbiologic clearance (51.13 versus 34.51 h; P < 0.001), the hospital LOS (15.40 versus 7.90 days; P = 0.027), and the intensive care unit LOS (5.55 versus 1.19 days; P = 0.035) were reduced. To achieve optimal outcomes, rapid identification with MALDI-TOF MS combined with real-time AMS intervention is more impactful than MALDI-TOF MS alone.

scholarly journals Evaluation of a Rapid and Simplified Protocol for Direct Identification of Microorganisms From Positive Blood Cultures by Using Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

2021 ◽  
Vol 11 ◽  
Author(s):  
Yufeng Dai ◽  
Xinyi Xu ◽  
Xue Yan ◽  
Daming Li ◽  
Wei Cao ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Blood Cultures ◽  
Laser Desorption Ionization ◽  
Direct Identification ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Early and rapid identification of microorganisms is critical for reducing the mortality rate caused by bloodstream infections (BSIs). The accuracy and feasibility of directly identifying pathogens in positive blood cultures by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been intensely confirmed. In this study, we combined density centrifugation and extra chemical lysis-extraction to develop an optimized method in the blood culture process, which significantly improved the effectiveness of direct identification by MALDI-TOF MS. The accuracy was evaluated by 2,032 positive blood culture samples (115 species of microorganism). The overall MALDI-TOF MS based identification rate with scores ≥ 1.700 was 87.60%. 94.06% of gram-negative bacteria were identified consistently to the genus level, followed by anaerobes (93.33%), gram-positive bacteria (84.46%), and fungi (60.87%). This protocol could obtain results within 10–20 min at a cost of less than $0.1 per sample, which saved up to 24 h in identifying 87.60% of the microorganism from positive blood cultures. This rapid and simplified protocol facilitates the direct identification of microorganism in positive blood cultures, and exhibits the advantages of cost-effective, time-saving, and easy-to-use. It could provide the causative organism of the patient to clinicians in time for targeted treatment and reduce mortality.

scholarly journals Lineage and serotype identification of Listeria monocytogenes by matrix-assisted laser desorption ionization-time of flight mass spectrometry

2019 ◽  
Vol 36 (No. 6) ◽  
pp. 452-458 ◽  
Author(s):  
Štěpán Koudelka ◽  
Tereza Gelbíčová ◽  
Markéta Procházková ◽  
Renáta Karpíšková
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Serotype Identification ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

The identification of Listeria species, lineages and serotypes remains a crucial issue not only in epidemic surveys, but also in monitoring of the diversity of bacteria in the food chain. The aim of this study was identification of L. monocytogenes strains at lineage and serotype level using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The performance of MALDI-TOF MS was tested to identify L. monocytogenes into two lineages (I and II) and four serotypes (1/2a, 1/2b, 1/2c and 4b) the most commonly found in humans and food. Total of 227 L. monocytogenes strains from different sources were subjected to the study. Some of strains (112) were used for main spectrum profile (MSP) library creation. Other strains of interest (115) were then correctly identified on the lineage level comparing with the library by MALDI-TOF MS analysis using Biotyper (90%) and ClinPro Tools (100%) software. The serotype identification with 55.7% (Biotyper) and 67.8% (ClinPro Tools) accuracy is rather a proof that under given conditions the method has not big potential to be used for serotyping. However, MALDI-TOF MS has a potential to identify lineages of L. monocytogenes of food and human origin.

scholarly journals Rapid Identification of Clinically Relevant Members of the Genus Exophiala by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Description of Two Novel Species, Exophiala campbellii and Exophiala lavatrina

2017 ◽  
Vol 55 (4) ◽  
pp. 1162-1176 ◽  
Author(s):  
Andrew M. Borman ◽  
Mark Fraser ◽  
Adrien Szekely ◽  
Daniel E. Larcombe ◽  
Elizabeth M. Johnson
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Exophiala is a ubiquitous pleomorphic genus comprising at least 40 species, many of which have been associated with superficial, visceral, or systemic infections in humans, other mammals, or cold-blooded animals. In this study, we investigated the potential of matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS) for the identification of Exophiala species. A total of 89 isolates (including 50 human and 4 animal clinical isolates) stored in the National Collection of Pathogenic Fungi were identified by PCR amplification and sequencing of internal transcribed spacer region 1. Eighty-three of the isolates corresponded to 16 known species within Exophiala/Rhinocladiella . The remaining six isolates are shown by phylogenetic analyses based on four loci to represent two novel Exophiala species. Four isolates from domestic bathrooms which form a sister species with Exophiala lecanii-corni are described here as Exophiala lavatrina sp. nov. The remaining two isolates, both from subcutaneous infections, are distantly related to Exophiala oligosperma and are described here as Exophiala campbellii sp. nov. The triazoles and terbinafine exhibited low MICs against all Exophiala isolates in vitro . MALDI-TOF MS successfully distinguished all 18 species and identified all isolates after appropriate reference spectra were created and added to commercial databases. Intraspecific mean log scores ranged from 1.786 to 2.584 and were consistently significantly higher than interspecific scores (1.193 to 1.624), with the exception of E. lecanii-corni and E. lavatrina , for which there was considerable log score overlap. In summary, MALDI-TOF MS allows the rapid and accurate identification of a wide range of clinically relevant Exophiala species.

scholarly journals Evaluation of Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry for Identification of Mycobacterium species, Nocardia species, and Other Aerobic Actinomycetes

2015 ◽  
Vol 54 (2) ◽  
pp. 376-384 ◽  
Author(s):  
S. P. Buckwalter ◽  
S. L. Olson ◽  
B. J. Connelly ◽  
B. C. Lucas ◽  
A. A. Rodning ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Aerobic Actinomycetes ◽  
Tof Ms ◽  
Matrix Assisted Laser

The value of matrix-assisted laser desorption ionization−time of flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria and yeasts is well documented in the literature. Its utility for the identification of mycobacteria andNocardiaspp. has also been reported in a limited scope. In this work, we report the specificity of MALDI-TOF MS for the identification of 162Mycobacteriumspecies and subspecies, 53Nocardiaspecies, and 13 genera (totaling 43 species) of other aerobic actinomycetes using both the MALDI-TOF MS manufacturer's supplied database(s) and a custom database generated in our laboratory. The performance of a simplified processing and extraction procedure was also evaluated, and, similar to the results in an earlier literature report, our viability studies confirmed the ability of this process to inactivateMycobacterium tuberculosisprior to analysis. Following library construction and the specificity study, the performance of MALDI-TOF MS was directly compared with that of 16S rRNA gene sequencing for the evaluation of 297 mycobacteria isolates, 148Nocardiaspecies isolates, and 61 other aerobic actinomycetes isolates under routine clinical laboratory working conditions over a 6-month period. MALDI-TOF MS is a valuable tool for the identification of these groups of organisms. Limitations in the databases and in the ability of MALDI-TOF MS to rapidly identify slowly growing mycobacteria are discussed.

scholarly journals Genotyping of Plasmodium falciparum Pyrimethamine Resistance by Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry

2004 ◽  
Vol 48 (2) ◽  
pp. 466-472 ◽  
Author(s):  
Florian Marks ◽  
Christian G. Meyer ◽  
Jürgen Sievertsen ◽  
Christian Timmann ◽  
Jennifer Evans ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Increasing resistance, recrudescences, and treatment failure have led to the replacement of chloroquine with the combination of pyrimethamine (PYR) and sulfadoxine (SDX) as the first-line antimalarial drugs for treatment of uncomplicated Plasmodium falciparum malaria in several areas where this disease is endemic. The development of resistance to PYR-SDX is favored by incomplete treatment courses or by subtherapeutic levels in plasma. PYR-SDX resistance has been associated with several single-nucleotide polymorphisms (SNPs) in the P. falciparum dihydrofolate reductase (pfdhfr) and the P. falciparum dihydropteroate synthetase (pfdhps) genes. We have established assays based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) that conveniently allow the identification of SNPs associated with PYR resistance. Variants occurring at codon positions 16, 51, 59, and 108 of the pfdhfr gene were analyzed by MALDI-TOF MS in synthetic oligonucleotides to determine the detection threshold. In addition, 63 blood samples from subjects with P. falciparum parasitemia of various degrees were analyzed. The results were compared to those obtained by DNA sequencing of the respective gene fragment. The results of MALDI-TOF MS and DNA sequencing were consistent in 40 samples. In 23 samples two or three pfdhfr variants were detected by MALDI-TOF assays, whereas DNA-sequencing revealed one variant only. Simultaneous detection of two different mutations by biplex assays was, in principle, feasible. As demonstrated by the example of PYR resistance, MALDI-TOF MS allows for rapid and automated high-throughput assessment of drug sensitivity in P. falciparum malaria.

scholarly journals Speciation of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

2005 ◽  
Vol 71 (10) ◽  
pp. 6292-6307 ◽  
Author(s):  
Robert E. Mandrell ◽  
Leslie A. Harden ◽  
Anna Bates ◽  
William G. Miller ◽  
William F. Haddon ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Campylobacter Coli ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Multiple strains of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis isolated from animal, clinical, or food samples have been analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Whole bacterial cells were harvested from colonies or confluent growth on agar and transferred directly into solvent and then to a spot of dried 3-methoxy-4-hydroxycinnamic acid (matrix). Multiple ions in the 5,000- to 15,000-Da mass range were evident in spectra for each strain; one or two ions in the 9,500- to 11,000-Da range were consistently high intensity. “Species-identifying” biomarker ions (SIBIs) were evident from analyses of multiple reference strains for each of the six species, including the genome strains C. jejuni NCTC 11168 and C. jejuni RM1221. Strains grown on nine different combinations of media and atmospheres yielded SIBI masses within ±5 Da with external instrument calibration. The highest-intensity C. jejuni SIBIs were cytosolic proteins, including GroES, HU/HCj, and RplL. Multiple intraspecies SIBIs, corresponding probably to nonsynonymous nucleotide polymorphisms, also provided some intraspecies strain differentiation. MALDI-TOF MS analysis of 75 additional Campylobacter strains isolated from humans, poultry, swine, dogs, and cats revealed (i) associations of SIBI type with source, (ii) strains previously speciated incorrectly, and (iii) “strains” composed of more than one species. MALDI-TOF MS provides an accurate, sensitive, and rapid method for identification of multiple Campylobacter species relevant to public health and food safety.

scholarly journals Application of Matrix-assisted Laser Desorption Ionization Time-of-flight Mass Spectrometry for Identification of Coagulase-negative Staphylococci Isolated from Milk of Cows with Subclinical Mastitis

2016 ◽  
Vol 19 (3) ◽  
pp. 627-632 ◽  
Author(s):  
T. Banach ◽  
M. Bochniarz ◽  
P. Łyp ◽  
Ł. Adaszek ◽  
W. Wawron ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Subclinical Mastitis ◽  
Laser Desorption Ionization ◽  
Coagulase Negative Staphylococci ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

AbstractThe aim of this study was to use matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of coagulase-negative staphylococci (CNS) isolated from the milk of cows with subclinical mastitis. The study material consisted of 33 isolates of CNS, identified by the results of API Staph tests, obtained from the milk of cows with subclinical mastitis. Based on the spectra analyses, MALDI-TOF MS tests of 33 bacterial samples allowed identification of the microorganisms in 27 cases (81.8%). The most frequent cause of subclinical mastitis was found to beStaphylococcussciuri (39%), whileS. vitulinuswas detected in 15% of the milk samples. The results obtained indicate that MALDI-TOF MS can be used for the identification of CNS isolated from bovine mastitis as a method supplementary to biochemical tests.

scholarly journals Current Status of Matrix-Assisted Laser Desorption/Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in Clinical Diagnostic Microbiology

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4775
Author(s):  
Sachio Tsuchida ◽  
Hiroshi Umemura ◽  
Tomohiro Nakayama
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Clinical Applications ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Mass spectrometry (MS), a core technology for proteomics and metabolomics, is currently being developed for clinical applications. The identification of microorganisms in clinical samples using matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS) is a representative MS-based proteomics application that is relevant to daily clinical practice. This technology has the advantages of convenience, speed, and accuracy when compared with conventional biochemical methods. MALDI-TOF MS can shorten the time used for microbial identification by about 1 day in routine workflows. Sample preparation from microbial colonies has been improved, increasing the accuracy and speed of identification. MALDI-TOF MS is also used for testing blood, cerebrospinal fluid, and urine, because it can directly identify the microorganisms in these liquid samples without prior culture or subculture. Thus, MALDI-TOF MS has the potential to improve patient prognosis and decrease the length of hospitalization and is therefore currently considered an essential tool in clinical microbiology. Furthermore, MALDI-TOF MS is currently being combined with other technologies, such as flow cytometry, to expand the scope of clinical applications.

scholarly journals Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry in Identification of Nontuberculous Mycobacteria

Chemotherapy ◽  
2016 ◽  
Vol 61 (4) ◽  
pp. 167-170 ◽  
Author(s):  
Ivana Mareković ◽  
Zrinka Bošnjak ◽  
Marko Jakopović ◽  
Zagorka Boras ◽  
Mateja Janković ◽  
...  
Keyword(s):  
Nontuberculous Mycobacteria ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Background/Aims: Species-level identification of nontuberculous mycobacteria (NTM) is important in making decisions about the necessity and choice of antimicrobial treatment. The reason is predictable clinical significance and the susceptibility profile of specific NTM species. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is recognized as a diagnostic tool for routine identification of bacteria and yeasts in the clinical laboratory based on protein fingerprint analysis. The aim of the study was to evaluate MALDI-TOF MS in the identification of NTM. Methods: A total of 25 NTM isolates from liquid cultures were identified with both polymerase chain reaction (PCR)-based hybridization assay and MALDI-TOF MS at the University Hospital Center Zagreb. Results: PCR-based hybridization assay identified 96% (24/25) and MALDI-TOF MS 80% (20/25) of tested NTM isolates. Five isolates with no reliable MALDI-TOF MS identification belonged to the Mycobacterium avium-intracellulare complex. Seventy percent (14/20) of NTM isolates successfully identified with MALDI-TOF MS had a score higher than 2.0, indicating reliable species identification. Conclusion: MALDI-TOF MS is a promising tool for the identification of NTM. With a further improvement of the protein extraction protocol, especially regarding the M. avium-intracellulare complex, MALDI-TOF MS could be an additional standard method for identification of NTM.

scholarly journals Bacterial Identification and Monitoring Around Two-Piece Dental Implants by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS)

2020 ◽  
Vol 12 (01) ◽  
pp. 49-55
Author(s):  
Sonali Saha ◽  
Ajita Meenawat ◽  
Chinmoy Sahu ◽  
Vivek Srivastava ◽  
Shivam Yadav ◽  
...  
Keyword(s):  
Dental Implants ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Abstract Context Early microbiological diagnosis and treatment of periodontal pathogens is important for successful retention of dental implants. Aims This study aimed to identify and monitor oral bacterial colonization after successful two-piece dental implants. Settings and Design In this study, 50 two-piece dental implant subjects were included and assessed clinically, radiographically, and microbiologically. Methods and Material All the parameters were recorded at various stages after prosthesis placement. In each stage, nonadherent (peri-implant sulcular fluid) and adherent (curetted inner threads) samples were collected. Semiquantitative anaerobic culture of the samples were done in Anoxomat system. Bacterial colonies were first identified by routine microbiological methods and then by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method. Statistical Analysis All the results were analyzed by appropriate statistical methods (Chi-square, one factor analysis of variance, etc.). Results All the bacterial isolates were identified in the MALDI-TOF MS system with no failure. After implant placement for the nonadherent samples, the frequency (%) of Fusobacterium nucleatum, Prevotella melaninogenica, and Propionibacterium acnes decreased whereas frequency (%) of Escherichia coli, Staphylococcus epidermidis, and Streptococcus mitis increased. For adherent samples, the frequency (%) of E. coli, Enterococcus faecalis, Porphyromonas gingivalis, P. melaninogenica, and Veillonella parvula decreased, whereas frequency (%) of S. mitis and Streptococcus mutans increased. The postimplant mean nonadherent and adherent bacterial load increased with time but not significantly over the periods (p = 0.302 and 0.123, respectively). Conclusion Combination of basic (semiquantitative culture method) and advanced microbiological method (MALDI-TOF MS) can be useful for accurate detection and monitoring of potential pathogens around two-piece dental implants.

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