Delineation of Stenotrophomonas maltophilia isolates from cystic fibrosis patients by fatty acid methyl ester profiles and matrix-assisted laser desorption/ionization time-of-flight mass spectra using hierarchical cluster analysis and principal component analysis 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 (n571) 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 (n520) and the environment (n511). 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. INTRODUCTIONCystic fibrosis (CF) or mucoviscidosis is a fatal autosomal recessive disorder that mainly affects the Caucasian population (O'Sullivan & Freedman, 2009). The incidence of CF varies around the world, but estimates show that 1 in 2000-3000 newborns in the European Union is affected by this genetic disorder (WHO, 2014). In recent years, various CF centres worldwide have reported an increasing prevalence of Stenotrophomonas maltophilia in CF patients (CFFPR, 2012). S. maltophilia commonly colonizes the respiratory tract of CF patients, but its pathogenic importance in the progression of CF lung disease has not yet been completely elucidated. There is an extensive discussion about whether S. maltophilia is simply a colonizing organism or whether it actually causes infection and consequently reduces the lung function in CF patients (Waters et al., 2011(Waters et al., , 2013. In addition, its multidrug resistance coupled with its ability to produce biofilms raises strong concerns in the medical community (Brooke, 2012).Identification of S. maltophilia can be achieved by a wide range of well-establish...
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. Bloodstream infections caused by Candida spp. are the most common invasive fungal infections (1, 2). Patients at risk of candidemia are those who are immunocompromised, e.g., those with hematologic and solid-organ malignancies, those receiving immunosuppressive therapy, those with chronic renal failure, and those treated with antibiotics or invasive catheters (2, 3). In the population of the United States, the incidence of hospital-acquired candidemia is as high as 10 cases per 100,000 patients (4). The 2013 annual epidemiological report of the European Centre for Disease Prevention and Control (ECDC) stated that Candida spp. are the fifth most frequently isolated microorganism in intensive care unit (ICU)-acquired bloodstream infections in the European Union (5). Mortality rates due to Candida bloodstream infections vary from 45% to 53% depending on the population investigated (6, 7). Although C. albicans is still the most frequently isolated Candida species in candidemia, non-albicans Candida species are increasingly found to be the causative agents (8-12).Of particular concern is emerging resistance to both the antifungal classes of azoles and the newer echinocandins, as recently reported in the World Health Organization's "Antimicrobial Resistance: Global Report on Surveillance 2014" (13). Resistance to antifungal drugs varies among the various species of Candida because of the intrinsically low susceptibility of C. glabrata to azole antifungals, such as fluconazole (FLC) (14), and because of multifactorial processes or mutations in the fks1 and fks2 genes (15,16). For the...
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.