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Karl Dichtl

Publications and source records attributed to Karl Dichtl.

2 recordsLinked to original sources

Rapid and reliable diagnosis of mucormycosis using colorimetric loop-mediated isothermal amplification.

Current diagnostic approaches for mucormycosis are often limited by low sensitivity and prolonged turnaround times, which result in delayed treatment and poor clinical outcomes. We developed a novel diagnostic method utilizing a colorimetric loop-mediated isothermal amplification (LAMP) assay for the rapid and sensitive detection of mucormycosis. The assay incorporates specifically designed primers capable of detecting as low as 0.001 picograms (pg) of spiked genomic DNA from Mucorales fungi. This LAMP assay demonstrated a high sensitivity of 98% and a 100% specificity of detecting fungal ribosomal DNA (rDNA) in bronchoalveolar lavage (BAL) samples collected from mice infected with Mucorales fungi (n = 48) or from an uninfected control group (n = 15). To align the assay with clinical antifungal therapy, a subset of infected mice was treated with either liposomal amphotericin B (LAMB) or a combination of LAMB and a humanized monoclonal antibody (VX-01) targeting the Mucorales-specific surface protein CotH3. Consistent with the treatment efficacy, the LAMP assay detected significantly lower fungal burdens in BAL samples from mice receiving the combination therapy compared to those treated with LAMB alone or placebo. Further validation was conducted using BAL samples from patients diagnosed with mucormycosis (n = 24) or aspergillosis (n = 17). The assay demonstrated a sensitivity of 79% and a specificity of 94%. These findings highlight the diagnostic potential of this LAMP-based assay as a point-of-care. Its high sensitivity, specificity, and rapid turnaround time position this assay as a promising tool for early and accurate detection of mucormycosis, with the potential to improve patient management and clinical outcomes.IMPORTANCEMucormycosis is a rapidly progressive and fatal fungal infection. Timely diagnosis is critical for effective treatment, yet current diagnostic tools are slow, insensitive, or require complex laboratory procedures. In this study, we developed and validated a colorimetric loop-mediated isothermal amplification (LAMP) assay that enables rapid and reliable detection of Mucorales DNA directly from bronchoalveolar lavage (BAL) specimens. The assay demonstrated high sensitivity and specificity in both experimental mouse models and clinical samples, producing results within 1 h without the need for sophisticated equipment. This simple, robust, and cost-effective molecular diagnostic tool holds great potential for early detection of mucormycosis, facilitating prompt antifungal therapy and improving patient survival.

Mucormycosis

Emergence of a Novel, Phenotypically Difficult-to-Detect Vancomycin-Resistant Enterococcus faecium Clone (ST117/CT7799).

A significant increase of vancomycin-resistant Enterococcus faecium (VREfm) infections was observed in South-Eastern Austria since 2024. The prolonged outbreak is caused by a novel vanB-VREfm clone (ST117/CT7799, "VREfmstyr"). This study characterizes the atypical difficult-to-detect resistance phenotype and assesses the genomic relatedness of the isolates. Patient and outbreak characteristics were investigated including whole genome sequencing of the isolates. Sensitivity of broth microdilution (BMD), gradient tests (GT), disk diffusion (DD), and automated susceptibility testing (VITEK2) was compared. The performance of commercial screening media was evaluated. From sporadic detections in early 2024 case numbers began to rise during the year. In 30/31 (97%) of all cases, intra-hospital transmission was considered likely and an association with invasive procedures was identified in most cases. Core genome multilocus sequence typing revealed only six allelic differences between VREfmstyr isolates collected in a 12-month period, all belonging to the E. faecium ST117/CT7799 lineage. BMD detected vancomycin resistance (MIC > 4 mg/L) in no more than 16/31 (52%) of isolates after 24 h incubation, while GT and DD misclassified all isolates. Only prolonged incubation improved the performance of these assays. VITEK2 analysis, however, correctly classified all 31 isolates. Of four commercially available VRE-screening agars, only one was capable of detecting VREfmstyr after 24 h incubation. The emergence and clonal dissemination of VREfm ST117/CT7799 reveals a serious diagnostic gap as commonly used diagnostic algorithms fail to reliably detect this resistance phenotype. Our findings should help to further evaluate the true geographical distribution and clinical significance of this novel VREfm clone.

Enterococcus faecium