eThe widespread use of antifungal agents, which is likely to expand with their enhanced availability, has promoted the emergence of drug-resistant strains. Antifungal susceptibility testing (AFST) is now an essential procedure for guiding appropriate antifungal therapy. Recently, we developed a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based method that enables the detection of fungal isolates with reduced echinocandin susceptibility, relying on the proteome changes that are detectable after a 15-h exposure of fungal cells to serial drug concentrations. Here, we describe a simplified version of this approach that facilitates discrimination of the susceptible and resistant isolates of Candida albicans after a 3-h incubation in the presence of "breakpoint" level drug concentrations of the echinocandin caspofungin (CSF). Spectra at concentrations of 0 (null), 0.03 (intermediate), and 32 (maximal) g/ml of CSF were used to create individual composite correlation index (CCI) matrices for 65 C. albicans isolates, including 13 fks1 mutants. Isolates are then classified as susceptible or resistant to CSF if the CCI values of spectra at 0.03 and 32 g/ml are higher or lower, respectively, than the CCI values of spectra at 0.03 and 0 g/ml. In this way, the drug resistance of C. albicans isolates to echinocandin antifungals can be quickly assessed. Furthermore, the isolate categorizations determined using MALDI-TOF MS-based AFST (ms-AFST) were consistent with the wild-type and mutant FKS1 genotypes and the AFST reference methodology. The ms-AFST approach may provide a rapid and reliable means of detecting emerging antifungal resistance and accelerating the initiation of appropriate antifungal treatment.
We report the first comparative evaluation between the Bruker Biotyper MS (BMS) and the Vitek MS (VMS) for the identification of yeasts. The rate of correct identifications at the species level was comparable using the commercial databases (89.8% versus 84.3%; P ؍ 0.712), but higher for BMS using an in-house-extended database (100% versus 84.3%; P ؍ 0.245). Importantly, the rate of misidentification was significantly higher for VMS (1% versus 12.1%; P < 0.0001), including the rate of major errors (0% versus 4.5%; P ؍ 0.0036). The introduction of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in the clinical microbiology laboratories is changing the approach to bacterial and fungal identification (1-4). In particular, several studies have already demonstrated the reliability of MALDI-TOF MS in the rapid identification of yeasts in different clinical settings (5-7), evidencing its cost-effectiveness in allowing the initiation of species-targeted antifungal therapy (7-9). To date, four MALDI-TOF MS systems are commercially available: the Microflex LT Biotyper (Bruker Daltonics, Bremen, Germany) (BMS), the Saramis system (bio-Mérieux, Marcy l'Etoile, France), the Vitek MS system (bioMérieux, Marcy l'Etoile, France) (VMS), and, very recently, the Andromas system (Andromas, Paris, France). Several comparative studies have already been performed using the most common systems (BMS and VMS), but, to the best of our knowledge, they have focused only on the identification of bacteria (10-13). Only very recently was a comparative study on yeasts performed using BMS and Saramis (bio-Mérieux, Marcy l'Etoile, France), the previously distributed version of VMS (14). In the present study, we evaluated the ability of BMS and VMS to identify a broad panel of yeasts of medical interest.One hundred ninety-seven isolates from different human samples, previously identified by conventional biochemical techniques or by sequencing the internal transcribed spacer 1 (ITS1) and ITS2 regions, were blindly identified using the two systems. In order to minimize the risk of misidentification related to the use of incomplete and error-filled public databases (15), the sequences obtained were compared to reference data available in two databases: GenBank, searched by using the nucleotide BLAST tool (blast.ncbi.nlm.nih.gov), and the CBS (Centraalbureau voor Schimmelcultures) yeast database (www.cbs.knaw.nl). The panel included 157 (79.7%) isolates belonging to 30 Candida or Candida-related species (Table 1), and 40 (20.3%) isolates belonging to 15 non-Candida species (Table 2). Before processing for MS identification, each isolate was cultured on Sabouraud dextrose (Kima, Padua, Italy) agar and incubated for 24 h at 35°C. For BMS, proteins were extracted as recommended by the manufacturer. Briefly, a loopful of yeasts was suspended in one volume of water and three volumes of absolute ethanol, and after centrifugation, the pellets were processed with an equal amount of formic acid and acetonitrile ...
Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful technique for identification of microorganisms, changing the workflow of well-established laboratories so that its impact on microbiological diagnostics has been unparalleled. In comparison with conventional identification methods that rely on biochemical tests and require long incubation procedures, MALDI-TOF MS has the advantage of identifying bacteria and fungi directly from colonies grown on culture plates in a few minutes and with simple procedures. Numerous studies on different systems available demonstrate the reliability and accuracy of the method, and new frontiers have been explored besides microbial species level identification, such as direct identification of pathogens from positive blood cultures, subtyping, and drug susceptibility detection.
In recent studies evaluating the usefulness of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based identification of yeasts for the routine diagnosis of fungal infections, preanalytical sample processing has emerged as a critical step for reliable MALDI-TOF MS outcomes, especially when the Bruker Daltonics Biotyper software was used. In addition, inadequate results often occurred due to discrepancies between the methods used for clinical testing and database construction. Therefore, we created an in-house MALDI-TOF MS library using the spectra from 156 reference and clinical yeast isolates (48 species in 11 genera), which were generated with a fast sample preparation procedure. After a retrospective validation study, our database was evaluated on 4,232 yeasts routinely isolated during a 6-month period and fast prepared for MALDI-TOF MS analysis. Thus, 4,209 (99.5%) of the isolates were successfully identified to the species level (with scores of >2.0), with 1,676 (39.6%) having scores of >2.3. For the remaining 23 (0.5%) isolates, no reliable identification (with scores of <1.7) was obtained. Interestingly, these isolates were almost always from species uniquely represented or not included in the database. As the MALDI-TOF MS results were, except for 23 isolates, validated without additional phenotypic or molecular tests, our proposed strategy can enhance the rapidity and accuracy of MALDI-TOF MS in identifying medically important yeast species. However, while continuous updating of our database will be necessary to enrich it with more strains/species of new and emerging yeasts, the present in-house MALDI-TOF MS library can be made publicly available for future multicenter studies.T o date, literature-based evidence has accumulated with respect to the reliability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of yeast isolates in diagnostic clinical microbiology laboratories (1-10). As already shown with bacteria, MALDI-TOF MS identifies yeasts with rapidity, accuracy, and superiority over conventional phenotypic methods (for review, see references 11-15).As an alternative to the ethanol/formic acid-based procedure, also referred to as complete tube extraction, recommended for use only with the Bruker MALDI Biotyper system (Bruker Daltonics, Bremen, Germany), the on-plate extraction or fast formic acid method (4, 16, 17), which consists of covering the smeared yeast colony with a formic acid solution, was proposed. Using the Bruker Biotyper 3.0 database and spectral scores of Ն1.7 as cutoffs for species-level identification, Theel et al. found that the formic acid-based direct on-plate method yielded identification percentages that were similar to those obtained with the more complex tube-based extraction method (18). Nonetheless, Van Herendael et al. showed that MALDI-TOF MS analysis using the short extraction method is suitable for the rapid identification of yeast isolates but that its use ...
The UV Index was established more than 20 years ago as a tool for sun protection and health care. Shortly after its introduction, UV Index monitoring started in several countries either by newly acquired instruments or by converting measurements from existing instruments into the UV Index. The number of stations and networks has increased over the years. Currently, 160 stations in 25 European countries deliver online values to the public via the Internet. In this paper an overview of these UV Index monitoring sites in Europe is given. The overview includes instruments as well as quality assurance and quality control procedures. Furthermore, some examples are given about how UV Index values are presented to the public. Through these efforts, 57% of the European population is supplied with high quality information, enabling them to adapt behaviour. Although health care, including skin cancer prevention, is cost-effective, a proportion of the European population still doesn't have access to UV Index information.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.