scholarly journals Investigation of Fluconazole Susceptibility to Candida Albicans by MALDI-TOF MS and Real-Time PCR for CDR1, CDR2, MDR1 and ERG11

2021 ◽  
Author(s):  
Chanika Maenchantrarath ◽  
Pradchama Khumdee ◽  
Seksun Samosornsuk ◽  
Narissara Mungkornkaew ◽  
Worada Samosornsuk
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Spectral Intensity ◽  
Spontaneous Mutant ◽  
Major Peak ◽  
Maldi Tof Ms ◽  
Clinical Strains ◽  
Mass Spectral ◽  
Maldi Tof ◽  
Tof Ms

Abstract Background C. albicans is the most important yeast that caused the infection in humans; the trend of resistance to fluconazole (FLC) was also increased, while the FLC susceptibility by conventional method takes time causing the treatment failure. To investigate FLC susceptibility to C. albicans using MALDI-TOF MS and Real-time PCR for CDR1, CDR2, MDR1 and ERG11, overall, 32 C. albicans strains included 4 reference strains (3 FLC susceptible (S) and 1 FLC resistant (R), 1 spontaneous mutant strain (FLC susceptible-dose dependent, SDD) and 27 clinical strains obtained from 2 Thai University Hospitals were performed FLC susceptibility testing by Sensititre YeastOne and broth microdilution method, FLC resistant expression mechanism by Real-time PCR and the major peak determination by MALDI-TOF MS.Results The change of CDR1 and CDR2 mRNA expression were only significantly observed in SDD and R strains. Using MALDI-TOF MS, the change of mass spectral intensity at range 3376-3382 m/z (major peak) was significantly related to FLC susceptibility as SDD (decreased at 4 µg/ml and increase at 8 µg/ml), S (all increased), and R (all slightly decreased or no change) after incubation for 6 h. All 27 clinical strains showed FLC MIC susceptible (MIC range 0.25-2 µg/ml), no change in CDR1 and CDR2 expression and S major peak type. The FLC resistance C. albicans with CDR1 and CDR2 expression may possibly effect the change of mass spectral intensity at range 3376-3382 m/z. Conclusions The MALDI-TOF MS may be used to simultaneously classify and predict FLC resistant C. albicans strains associated with CDR1 and CDR2 expression. Further studies are essential to clarify the methodology and improve the reliability of this assay for routine diagnosis.

Effects of inactivation methods on the analysis ofBacillus atrophaeusendospores using real-time PCR and MALDI-TOF-MS

2010 ◽  
pp. NA-NA ◽  
Author(s):  
Steven R. Talbot ◽  
Heiko Russmann ◽  
Stefan Köhne ◽  
Bärbel Niederwöhrmeier ◽  
Gudrun Grote ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

scholarly journals Simultaneous Detection of Seven Human Coronaviruses by Multiplex PCR and MALDI-TOF MS

COVID ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 5-17
Author(s):  
Tingting Liu ◽  
Lin Kang ◽  
Yanwei Li ◽  
Jing Huang ◽  
Zishuo Guo ◽  
...  
Keyword(s):  
Multiplex Pcr ◽  
Real Time ◽  
Real Time Pcr ◽  
Simultaneous Detection ◽  
Detection Sensitivity ◽  
Clinical Samples ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Human Coronaviruses ◽  
Tof Ms

Human coronaviruses (HCoVs) are associated with a range of respiratory symptoms. The discovery of severe acute respiratory syndrome (SARS)-CoV, Middle East respiratory syndrome, and SARS-CoV-2 pose a significant threat to human health. In this study, we developed a method (HCoV-MS) that combines multiplex PCR with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), to detect and differentiate seven HCoVs simultaneously. The HCoV-MS method had high specificity and sensitivity, with a 1–5 copies/reaction detection limit. To validate the HCoV-MS method, we tested 163 clinical samples, and the results showed good concordance with real-time PCR. Additionally, the detection sensitivity of HCoV-MS and real-time PCR was comparable. The HCoV-MS method is a sensitive assay, requiring only 1 μL of a sample. Moreover, it is a high-throughput method, allowing 384 samples to be processed simultaneously in 30 min. We propose that this method be used to complement real-time PCR for large-scale screening studies.

scholarly journals A dual approach employing MALDI-TOF MS and real-time PCR for fast species identification within the Enterobacter cloacae complex

2012 ◽  
Vol 328 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Melanie Pavlovic ◽  
Regina Konrad ◽  
Azuka N. Iwobi ◽  
Andreas Sing ◽  
Ulrich Busch ◽  
...  
Keyword(s):  
Real Time ◽  
Species Identification ◽  
Real Time Pcr ◽  
Enterobacter Cloacae ◽  
Dual Approach ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Enterobacter Cloacae Complex ◽  
Tof Ms

scholarly journals Rapid Identification of Mycoplasma bovis Strains from Bovine Bronchoalveolar Lavage Fluid with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry after Enrichment Procedure

2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Jade Bokma ◽  
Laura Van Driessche ◽  
Piet Deprez ◽  
Freddy Haesebrouck ◽  
Marianne Vahl ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Lavage Fluid ◽  
Rapid Identification ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

ABSTRACT Mycoplasma bovis is a leading cause of pneumonia in modern calf rearing. Fast identification is essential to ensure appropriate antimicrobial therapy. Therefore, the objective of this study was to develop a protocol to identify M. bovis from bronchoalveolar lavage fluid (BALf) with matrix-assisted laser desorption ionization–time of flight mass spectrometry MALDI-TOF MS and to determine the diagnostic accuracy in comparison with other techniques. BALf was obtained from 104 cattle, and the presence of M. bovis was determined in the following three ways: (i) rapid identification of M. bovis with MALDI-TOF MS (RIMM) (BALf was enriched and after 24, 48, and 72 h of incubation and was analyzed using MALDI-TOF MS), (ii) triplex real-time PCR for M. bovis, Mycoplasma bovirhinis, and Mycoplasma dispar, and (iii) 10-day incubation on selective-indicative agar. The diagnostic accuracy of the three tests was determined with Bayesian latent class modeling (BLCM). After 24 h of enrichment, M. bovis was identified with MALDI-TOF MS in 3 out of 104 BALf samples. After 48 and 72 h of enrichment, 32/104 and 38/100 samples, respectively, were M. bovis positive. Lipase-positive Mycoplasma-like colonies were seen in 28 of 104 samples. Real-time PCR resulted in 28/104 positive and 12/104 doubtful results for M. bovis. The BLCM showed a sensitivity (Se) and specificity (Sp) of 86.6% (95% credible interval [CI], 69.4% to 97.6%) and 86.4% (CI, 76.1 to 93.8) for RIMM. For real-time PCR, Se was 94.8% (CI, 89.9 to 97.9) and Sp was 88.9% (CI, 78.0 to 97.4). For selective-indicative agar, Se and Sp were 70.5% (CI, 52.1 to 87.1) and 93.9% (CI, 85.9 to 98.4), respectively. These results suggest that rapid identification of M. bovis with MALDI-TOF MS after an enrichment procedure is a promising test for routine diagnostics in veterinary laboratories.

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 Development and Validation of an in-House Library of Colombian Candida auris Strains with MALDI-TOF MS to Improve Yeast Identification

2020 ◽  
Vol 6 (2) ◽  
pp. 72 ◽  
Author(s):  
Andrés Ceballos-Garzon ◽  
Daniela Amado ◽  
Norida Vélez ◽  
María José Jiménez-A ◽  
Crescencio Rodríguez ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Candida Auris ◽  
Yeast Identification ◽  
Great Opportunity ◽  
Maldi Tof Ms ◽  
Identification Process ◽  
Clinical Strains ◽  
Maldi Tof ◽  
Development And Validation ◽  
Tof Ms

Background: Candida auris is characterized for having a high genetic variability among species. MALDI-TOF MS library contains spectra from only three strains of C. auris, which makes difficult the identification process and gives low scores at the species level. Our aim was to construct and validate an internal library to improve C. auris identification with Colombian clinical strains. Methods: From 30 clinical strains, 770 mass spectra were obtained for the construction of the database. The validation was performed with 300 strains to compare the identification results in the BDAL and C. auris Colombia libraries. Results: Our library allowed a complete, 100% identification of the evaluated strains and a significant improvement in the scores obtained, showing a better performance compared to the Bruker BDAL library. Conclusions: The strengthening of the database is a great opportunity to improve the scoring and C. auris identification. Library data are available via ProteomeXchange with identifier PXD016387.

scholarly journals Factors Associated With MALDI-TOF Mass Spectral Quality of Species Identification in Clinical Routine Diagnostics

2021 ◽  
Vol 11 ◽  
Author(s):  
Aline Cuénod ◽  
Frédéric Foucault ◽  
Valentin Pflüger ◽  
Adrian Egli
Keyword(s):  
Species Identification ◽  
Burkholderia Cepacia ◽  
Bacterial Species ◽  
Clinical Diagnostics ◽  
Spectral Quality ◽  
Bacterial Colony ◽  
Maldi Tof Ms ◽  
Mass Spectral ◽  
Maldi Tof ◽  
Tof Ms

BackgroundAn accurate and timely identification of bacterial species is critical in clinical diagnostics. Species identification allows a potential first adaptation of empiric antibiotic treatments before the resistance profile is available. Matrix assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS) is a widely used method for bacterial species identification. However, important challenges in species identification remain. These arise from (i) incomplete databases, (ii) close relatedness of species of interest, and (iii) spectral quality, which is currently vaguely defined.MethodsWe selected 47 clinically relevant bacterial isolates from 39 species, which can be challenging to identify by MALDI-TOF MS. We measured these isolates under various analytical conditions on two MALDI-TOF MS systems. First, we identified spectral features, which were associated with correct species identification in three different databases. Considering these features, we then systematically compared spectra produced with three different sample preparation protocols. In addition, we varied quantities of bacterial colony material applied and bacterial colony age.ResultsWe identified (i) the number of ribosomal marker peaks detected, (ii) the median relative intensity of ribosomal marker peaks, (iii) the sum of the intensity of all detected peaks, (iv) a high measurement precision, and (v) reproducibility of peaks to act as good proxies of spectral quality. We found that using formic acid, measuring bacterial colonies at a young age, and frequently calibrating the MALDI-TOF MS device increase mass spectral quality. We further observed significant differences in spectral quality between different bacterial taxa and optimal measurement conditions vary per taxon.ConclusionWe identified and applied quality measures for MALDI-TOF MS and optimized spectral quality in routine settings. Phylogenetic marker peaks can be reproducibly detected and provide an increased resolution and the ability to distinguish between challenging species such as those within the Enterobacter cloacae complex, Burkholderia cepacia complex, or viridans streptococci.

scholarly journals Evaluation of Vitek MS for Differentiation of Cryptococcus neoformans and Cryptococcus gattii Genotypes

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Lumena P. Machado Siqueira ◽  
Viviane M. Favero Gimenes ◽  
Roseli Santos de Freitas ◽  
Márcia de Souza Carvalho Melhem ◽  
Lucas Xavier Bonfietti ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Cryptococcus Gattii ◽  
Correct Identification ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Mass Spectral ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Tof Ms

ABSTRACT Cryptococcus neoformans and Cryptococcus gattii are the main pathogenic species of invasive cryptococcosis among the Cryptococcus species. Taxonomic studies have shown that these two taxa have different genotypes or molecular types with biological and ecoepidemiological peculiarities. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been proposed as an alternative method for labor-intensive methods for C. neoformans and C. gattii genotype differentiation. However, Vitek MS, one of the commercial MALDI-TOF MS instruments, has not been yet been evaluated for this purpose. Thus, we constructed an in-house database with reference strains belonging to the different C. neoformans (VNI, VNII, VNIII, and VNIV) and C. gattii (VGI, VGII, VGIII, and VGIV) major molecular types by using the software Saramis Premium (bioMérieux, Marcy-l’Etoile, France). Then, this new database was evaluated for discrimination of the different genotypes. Our in-house database provided correct identification for all C. neoformans and C. gattii genotypes; however, due to the intergenotypic mass spectral similarities, a careful postanalytic evaluation is necessary to provide correct genotype identification.

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