Till T. Bachmann

Antimicrobial susceptibility testing (AST) technologies help to accelerate the initiation of targeted antimicrobial therapy for patients with infections and could potentially extend the lifespan of current narrow-spectrum antimicrobials. Although conceptually new and rapid AST technologies have been described, including new phenotyping methods, digital imaging and genomic approaches, there is no single major, or broadly accepted, technological breakthrough that leads the field of rapid AST platform development. This might be owing to several barriers that prevent the timely development and implementation of novel and rapid AST platforms in health-care settings. In this Consensus Statement, we explore such barriers, which include the utility of new methods, the complex process of validating new technology against reference methods beyond the proof-of-concept phase, the legal and regulatory landscapes, costs, the uptake of new tools, reagent stability, optimization of target product profiles, difficulties conducting clinical trials and issues relating to quality and quality control, and present possible solutions. This Consensus Statement presents the barriers that currently prevent the timely development and implementation of novel and rapid antimicrobial susceptibility testing platforms, including the costs involved, uptake of new tools, legal and regulatory aspects, difficulties conducting clinical trials and quality control, and presents possible solutions.

Circulating biomarkers are on the verge of becoming powerful diagnostic tools for various human diseases. However, the complex sample composition makes it difficult to detect biomarkers directly from blood at the bench or at the point-of-care. Blood cells are often a source of variability of the biomarker signal. While the interference of hemoglobin is a long known source of variability, the release of nucleic acids and other cellular components from hemocytes is a new concern for measurement and detection of circulating extracellular markers. Research into miniaturised blood plasma separation has been thriving in the last 10 years (2006-2016). Most point-of-care systems need microscale blood plasma separation, but developed solutions differ in complexity and sample volume range. But could blood plasma separation be avoided completely? This focused review weights the advantages and limits of miniaturised blood plasma separation and highlights the most interesting advances in direct capture as well as smart blood plasma separation.

Invasive fungal infections have emerged as a major cause of morbidity and mortality in immunocompromised patients. Conventional identification of pathogenic fungi in clinical microbiology laboratories is time-consuming and, therefore, often imperfect for the early initiation of an adequate antifungal therapy. We developed a diagnostic microarray for the rapid and simultaneous identification of the 12 most common pathogenic Candida and Aspergillus species. Oligonucleotide probes were designed by exploiting the sequence variations of the internal transcribed spacer (ITS) regions of the rRNA gene cassette to identify Candida albicans, Candida dubliniensis, Candida krusei, Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida guilliermondii, Candida lusitaniae, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and Aspergillus terreus. By using universal fungal primers (ITS 1 and ITS 4) directed toward conserved regions of the 18S and 28S rRNA genes, respectively, the fungal ITS target regions could be simultaneously amplified and fluorescently labeled. To establish the system, 12 pre-characterized fungal strains were analyzed; and the method was validated by using 21 clinical isolates as blinded samples. As the microarray was able to detect and clearly identify the fungal pathogens within 4 h after DNA extraction, this system offers an interesting potential for clinical microbiology laboratories.