Long-term carriage and evolution of VREfmLong-term carriage and evolution of vancomycin-resistant Enterococcus faecium: a genomic study on consecutive isolates.

Objectives: To determine if vancomycin-resistant Enterococcus faecium (VREfm) carriers carry the same VREfm clone after a minimum follow-up of 365 days. For those carrying the same clone, we investigated the genomic evolution per year per genome. Methods: We used WGS results to assign VREfm clones to each isolate and determine clone shifts. Finally, we calculated distance in core-genome MLST alleles, and the number of SNPs between consecutive VREfm isolates from patients carrying the same VREfm clone. Results: In total, 44.2% of patients carried the same VREfm clone, and the genomic evolution was 1.8 alleles and 2.6 SNPs per genome per year. Conclusions: In our population of long-term carriers, we calculated a molecular clock of 2.6 SNPs.

First cases of SARS-CoV-2 BA.2.86 in Denmark, 2023.

We describe 10 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant BA.2.86 detected in Denmark, including molecular characteristics and results from wastewater surveillance that indicate that the variant is circulating in the country at a low level. This new variant with many spike gene mutations was classified as a variant under monitoring by the World Health Organization on 17 August 2023. Further global monitoring of COVID-19, BA.2.86 and other SARS-CoV-2 variants is highly warranted.

Closed genomes uncover a saltwater species of Candidatus Electronema and shed new light on the boundary between marine and freshwater cable bacteria.

Cable bacteria of the Desulfobulbaceae family are centimeter-long filamentous bacteria, which are capable of conducting long-distance electron transfer. Currently, all cable bacteria are classified into two candidate genera: Candidatus Electronema, typically found in freshwater environments, and Candidatus Electrothrix, typically found in saltwater environments. This taxonomic framework is based on both 16S rRNA gene sequences and metagenome-assembled genome (MAG) phylogenies. However, most of the currently available MAGs are highly fragmented, incomplete, and thus likely miss key genes essential for deciphering the physiology of cable bacteria. Also, a closed, circular genome of cable bacteria has not been published yet. To address this, we performed Nanopore long-read and Illumina short-read shotgun sequencing of selected environmental samples and a single-strain enrichment of Ca. Electronema aureum. We recovered multiple cable bacteria MAGs, including two circular and one single-contig. Phylogenomic analysis, also confirmed by 16S rRNA gene-based phylogeny, classified one circular MAG and the single-contig MAG as novel species of cable bacteria, which we propose to name Ca. Electronema halotolerans and Ca. Electrothrix laxa, respectively. The Ca. Electronema halotolerans, despite belonging to the previously recognized freshwater genus of cable bacteria, was retrieved from brackish-water sediment. Metabolic predictions showed several adaptations to a high salinity environment, similar to the "saltwater" Ca. Electrothrix species, indicating how Ca. Electronema halotolerans may be the evolutionary link between marine and freshwater cable bacteria lineages.

QEPAS sensor in a butterfly package and its application.

Molecular gases are highly relevant in healthcare, production control, safety, and environmental monitoring. They often appear in small concentrations. The measurement of trace gases has increasingly become a key technique in those domains. Quartz-enhanced photoacoustic spectroscopy (QEPAS) is a suitable method that can provide the required low detection limits in such applications at comparatively low cost and small size. For mobile implementation, the size of an entire sensor unit matters. In this paper, we present a QEPAS sensor that fits into a standard butterfly package, its characterization, and its application on CH4 and CO2.

High speed external cavity diode laser concept based on a resonantly driven MEMS scanner for the mid-infrared region.

The rapid detection of trace gases is of great relevance for various spectroscopy applications. In this regard, the technology of external cavity diode lasers (ECDLs) has firmly established itself due to its excellent properties. Outside of the laboratory environment, however, these still have some restrictions, especially with regard to high acquisition rates for sensitive spectroscopy applications and mode-hop-free tuning. In this article, we present our innovative GaSb-based ECDL concept, in which a resonantly driven microelectromechanical system actuator is used. With this, a defined frequency range can be tuned extremely fast and without mode hops. Results of the characterization and its use for the rapid detection of trace gases are presented.

Comparison of the spectral excitation behavior of methane according to InP, GaSb, IC, and QC lasers as excitation source by sensor applications.

The MIR wavelength regime promises better gas detection possibilities than the NIR or the visible region because of the higher absorbencies simulated by HITRAN. In the MIR region are many important absorption lines of significant gases, which are relevant in healthcare, production supervision, and safety and environmental monitoring. One of those gases is methane. CH4 shows significant variations in absorbance with a maximum at 3.3 µm, which results in low detection limits in the range of low ppm. Interband-cascade- and quantum-cascade-based lasers emit at higher wavelengths, where the absorbencies of methane are higher. The comparison is done by analyzing the performance of two spectroscopy applications: tunable diode laser absorption spectroscopy and quartz-enhanced photoacoustic spectroscopy.

QEPAS sensor for breath analysis: a behavior of pressure.

The measurement of trace gases has increasingly become a key technique in healthcare and other medical applications. Quartz-enhanced photoacoustic spectroscopy (QEPAS) is a suitable method that can provide the required characteristics in such applications for a comparatively low cost and small size. The quantitative detection and a low detection limit are also required by applications. In this paper, we present new results on sensing biomedically relevant gases using the on-beam QEPAS technique with some newly developed tunable high-power single-mode laser diodes based on GaSb material. The data processing and detection limit determination are done by a field programmable gate array device, as well as an automatic measurement of the resonance frequency.