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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is a fast and inexpensive method for bacterial identification. The aim of this study was to analyze the performance of Vitek MS in identifying 160 nontuberculous mycobacterial isolates of 24 species from Lowenstein-Jensen solid medium and BACTEC MGIT 960 liquid medium using a bead-based method. The system correctly identified 76.9% of the isolates (123 of 160) cultivated on solid medium and 76.9% (123 of 160) of positive liquid cultures. None of the isolates included in the study was misidentified. Although the overall performance of Vitek MS with the SARAMIS 4.12 database was comparable in identifying mycobacterial species grown on solid medium and in liquid medium, the identification rate varied notably between the various species analyzed, which currently limits the utility for identification in routine diagnostics for some species., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Candidemia is an important cause of morbidity and mortality in immunosuppressed patients. Candida isolates must be cultivated, identified, and tested for susceptibility. We compared the performance of a new colorimetric broth microdilution panel (SensiQuattro Candida EU) for antifungal susceptibility testing to that of Liofilchem's MIC test strip and the EUCAST reference broth microdilution protocol. We tested 187 blood culture isolates of 5 Candida spp. (120 C. albicans, 38 C. glabrata, 10 C. parapsilosis, 12 C. tropicalis, and 7 C. krusei) against seven antifungal agents (amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin, and micafungin) and interpreted the MICs according to the EUCAST recommendations. If applicable, the overall essential agreement (EA) of the SensiQuattro panel with the reference broth microdilution was slightly higher for C. albicans (87%) than for other species (85.8%). We found that SensiQuattro performed best in testing amphotericin B (EA, 100%), voriconazole (EA, 93.7%), and posaconazole (EA, 94.8%) against C. albicans, but its error rate for this species was high (29.6%) because of mainly major errors (26.7%) in testing anidulafungin and micafungin. Compared to the SensiQuattro panel, the MIC test strip exhibited a higher level of agreement for most isolates. SensiQuattro assays are easy to perform, but they are currently not suitable for testing echinocandins against Candida spp., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Stenotrophomonas maltophilia is an opportunist multidrug-resistant pathogen that causes a wide range of nosocomial infections. Various cystic fibrosis (CF) centres have reported an increasing prevalence of S. maltophilia colonization/infection among patients with this disease. The purpose of this study was to assess specific fingerprints of S. maltophilia isolates from CF patients (n = 71) by investigating fatty acid methyl esters (FAMEs) through gas chromatography (GC) and highly abundant proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and to compare them with isolates obtained from intensive care unit (ICU) patients (n = 20) and the environment (n = 11). Principal component analysis (PCA) of GC-FAME patterns did not reveal a clustering corresponding to distinct CF, ICU or environmental types. Based on the peak area index, it was observed that S. maltophilia isolates from CF patients produced significantly higher amounts of fatty acids in comparison with ICU patients and the environmental isolates. Hierarchical cluster analysis (HCA) based on the MALDI-TOF MS peak profiles of S. maltophilia revealed the presence of five large clusters, suggesting a high phenotypic diversity. Although HCA of MALDI-TOF mass spectra did not result in distinct clusters predominantly composed of CF isolates, PCA revealed the presence of a distinct cluster composed of S. maltophilia isolates from CF patients. Our data suggest that S. maltophilia colonizing CF patients tend to modify not only their fatty acid patterns but also their protein patterns as a response to adaptation in the unfavourable environment of the CF lung., (© 2014 The Authors.)