Publications by authors named "Oliver Bader"

Article Synopsis
  • * The study reveals that a phenomenon called heteroresistance, where a small population of fungal cells can resist treatment, is responsible for these infections and is prevalent among clinical isolates from different regions.
  • * To address this, researchers developed a machine learning tool that can quickly identify heteroresistance in C. parapsilosis using genomic data, which could enhance diagnosis and treatment strategies for affected patients.
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Introduction: Although child morbidity and mortality could be reduced in Sub-Saharan Africa during the last years both remain high. Since neonatal infections play a major role, we conducted a cross-sectional pilot study in the lake region of Western Tanzania in order to analyze not only the prevalence of neonatal infection with its bacterial etiology including antimicrobial resistance pattern but also to detect potential maternal risk factors.

Methods: We screened 156 women for potential risk factors and examined their neonates for clinical signs of an infection including microbiological verification.

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Diarrhea is the second leading cause of death mainly effecting young children. Often it is the result of fecal-oral pathogen transmission. We aimed to investigate whether monitoring the prevalence of Gram-negative bacteria on the hands of asymptomatic children is suitable as an indicator of fecal contamination of the environment in their playground.

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The aim of the study was to examine the applicability of bioactive and antibacterial nanoparticles to an experimental adhesive. The adhesive (60 wt% BisGMA, 15 wt% TEGDMA, 25 wt% HEMA) was mixed with combinations of 5 wt% methacryl-functionalized polyhedral oligomeric silsesquioxane (MA-POSS) and one kind of bioactive/antibacterial nanoparticles: 1 wt% core-shell silica-silver nanoparticle (SiO@Ag), 1 wt% bioactive glass with bismuth (BAG-Bi) or 1 wt% calcium phosphate (CAP). Pure adhesive served as control.

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Oral candidiasis remains a common problem in HIV-infected individuals, especially in sub-Saharan Africa. Here, we performed the first study in Chad on the prevalence of oral yeasts carriage and oral candidiasis in HIV-positive subjects from southern Chad and analyzed the influence of HAART, CD4 T-cell numbers, and antimycotics in 589 patients. These patients were recruited from a specialized medical center for HIV patients in Sarh and from a rural medical health dispensary in the vicinity, including a total of 384 HIV-positive and 205 HIV-negative individuals.

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Magnusiomyces clavatus and Magnusiomyces capitatus are emerging yeasts with intrinsic resistance to many commonly used antifungal agents. Identification is difficult, and determination of susceptibility patterns with commercial and reference methods is equally challenging. For this reason, few data on invasive infections by spp.

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is among the most prevalent causes of candidiasis. Unlike , it is not capable of changing morphology between yeast and hyphal forms but instead has developed other virulence factors. An important feature is its unprecedented large repertoire of predicted cell wall adhesins, which are thought to enable adherence to a variety of surfaces under different conditions.

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Background: Yeasts of the CTG-clade lineage, which includes the human-infecting Candida albicans, Candida parapsilosis and Candida tropicalis species, are characterized by an altered genetic code. Instead of translating CUG codons as leucine, as happens in most eukaryotes, these yeasts, whose ancestors are thought to have lost the relevant leucine-tRNA gene, translate CUG codons as serine using a serine-tRNA with a mutated anticodon, [Formula: see text]. Previously reported experiments have suggested that 3-5% of the CTG-clade CUG codons are mistranslated as leucine due to mischarging of the [Formula: see text].

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In Aspergillus fumigatus, the repetitive region of the gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR amplification and Sanger sequencing of only a single marker, typing is readily available to most laboratories and highly reproducible. Here, I evaluate the usefulness of the marker for resistance detection and epidemiologic stratification among A.

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The intriguing recent discovery of strains, especially of clade 1, that (i) possess mosaic / alleles, (ii) demonstrate mixed multilocus sequence types (MLSTs) and (iii) have undergone genome-wide introgression has led to the speculation that these two species may be involved in an accelerated rate of horizontal gene transfer that is progressively leading to the merging of both species in a process coined 'despeciation'. In an MLST-based neighbour-joining tree of a number of and isolates of different clades, three prominent isolates formed a seemingly separate cluster besides the previously described and clades. In the light of the suspected, ongoing genetic introgression between the and species, this cluster of isolates is proposed to present one of the hybrid clonal complexes in the despeciation process of the genus.

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In elderly patients, several morbidities or medical treatments predisposing for fungal infections occur at a higher frequency, leading to high mortality and morbidity in this vulnerable patient group. Often, this is linked to an innately azole-resistant yeast species such as or . Additionally, host age per se and the wearing of dentures have been determined to influence the mix of colonizing species and, consequently, the species distribution of invasive fungal infections.

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Invasive candidiasis (IC) is associated with high morbidity and mortality in hospitalized patients if not diagnosed early. Long-term use of central venous catheters is a predisposing factor for IC. Hyphal forms of (the major etiological agent of IC) are related to invasion of host tissues.

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This study was performed as a head-to-head comparison of the performance characteristics of (1) two SARS-CoV-2-specific rapid antigen assays with real-time PCR as gold standard as well as (2) a fully automated high-throughput transcription-mediated amplification (TMA) assay and real-time PCR in a latent class analysis-based test comparison without a gold standard with several hundred samples in a low prevalence "real world" setting. Recorded sensitivity and specificity of the NADAL and the LumiraDx antigen assays and the Hologic Aptima SARS-CoV-2 TMA assay were 0.1429 (0.

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Yeasts of the / species complexes are human pathogens mostly in immune compromised individuals, and can cause infections from dermal lesions to fungal meningitis. Differences in virulence and antifungal drug susceptibility of species in these complexes indicate the value of full differentiation to species level in diagnostic procedures. MALDI-TOF MS has been reported to sufficiently discriminate these species.

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is among the most frequent causes of candidiasis. Clinical isolates of this species show large variations in colony morphotype, ranging from round and smooth to a variety of non-smooth irregular colony shapes. A non-smooth appearance is related to increased formation of pseudohyphae, higher capacity to form biofilms on abiotic surfaces, and invading agar.

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Background: Fungal spores are ubiquitous allergens. Severe forms of asthma are particularly highly associated with fungal sensitization. National and international asthma guidelines recommend the implementation of allergen immunotherapy if indicated.

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is a frequent cause of fungal bloodstream infections, especially in critically ill neonates or immunocompromised patients. Due to the formation of biofilms, the use of indwelling catheters and other medical devices increases the risk of infection and complicates treatment, as cells embedded in biofilms display reduced drug susceptibility. Therefore, biofilm formation may be a significant clinical parameter, guiding downstream therapeutic choices.

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Pathogen identification is a critical step during diagnosis of infectious diseases. Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry (MALDI-TOF-MS) has become the gold standard for identification of microorganisms cultured on solid media in microbiology laboratories. Direct identification of microbes from liquid specimen, circumventing the need for the additional overnight cultivation step, has been successfully established for blood culture, urine and liquor.

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Infectious diseases are worldwide a major cause of morbidity and mortality. Fast and specific detection of pathogens such as bacteria is needed to combat these diseases. Optimal methods would be non-invasive and without extensive sample-taking/processing.

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The human pathogenic yeast has gained significant importance over the past decades as one of the principal causes of fungal bloodstream infections. Isolates of are known to be able to switch between several different colony morphologies in vitro, which are correlated with different cell shapes, altered cell surface properties, and thus different capacities to form biofilms on indwelling medical devices. In a set of six clinical specimens from a single surgery patient yielding stable smooth- as well as crepe-morphology isolates, we investigated the differences between five of them on a phenotypic and genomic level.

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is a major human pathogen. In contrast, and the recently described , the two species most closely related to , are not known to be pathogenic. Some of the genetic determinants of virulence (or "cards of virulence") that A.

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The yeast Candida glabrata has emerged, second only to Candida albicans, to be one of the most frequently isolated fungi in clinical specimen from human. Its frequent resistance towards azole antifungal drugs and the high capacity to form biofilms on indwelling catheters of individual isolates render it an often difficult to treat pathogen. Hence, there is a notably increasing scientific and clinical interest in this species.

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, a Gram-positive spore-forming bacterium, is the leading cause of nosocomial diarrhea worldwide and therefore a substantial burden to the healthcare system. During the past decade, hypervirulent PCR-ribotypes (RT) e.g.

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Heterozygous gain-of-function (GOF) mutations in the cytokine-regulated transcription factor STAT1 (signal transducer and activator of transcription 1) lead to chronic mucocutaneous candidiasis (CMC). However, the molecular basis of these pathogenic missense mutations is largely unknown. In this study, we characterized in more detail the CMC-associated GOF substitution mutation of arginine-to-tryptophan at position 274 (R274W) and, in addition, the adjacent glutamine-to-alanine mutation at position 275 (Q275A).

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