Biology subjects

Lüth, S.

Publications and source records attributed to Lüth, S..

2 recordsLinked to original sources

bioRxiv2023

Large-scale phenotypic and genomic characterization of Listeria monocytogenes susceptibility to quaternary ammonium compounds

Listeria monocytogenes is a significant concern for the food industry due to its ability to persist in the food processing environment. Decreased susceptibility to disinfectants is one of the factors that contribute to the persistence of L. monocytogenes. The objective of this study was to explore the diversity of L. monocytogenes susceptibility to quaternary ammonium compounds (QACs) using 1,671 L. monocytogenes isolates. This was used to determine the phenotype-genotype concordance and characterize genomes of the QAC sensitive and tolerant isolates for stress resistance, virulence and plasmid replicon genes. Distribution of QAC tolerance genes among 37,897 publicly available L. monocytogenes genomes were also examined. The minimum inhibitory concentration to QACs was determined by the broth microdilution method and non-sequenced isolates (n=1,244) were whole genome sequenced. Genotype-phenotype concordance was 99% for benzalkonium chloride, DDAC and a commercial QAC based sanitizer. Prevalence of QAC tolerance genes was 23% and 28% in our L. monocytogenes collection and in the global dataset, respectively. qacH was the most prevalent gene in our collection (61%), with 19% prevalence in the global dataset. Notably, bcrABC was most common (72%) globally, while 25% in our collection. Prevalence of emrC and emrE was comparable in both datasets, 7% and 2%, respectively. Replicon genes, indicative of plasmid harborage, were detected in 44% of the isolates and associated with the QAC tolerant phenotype. The presented analysis is based on the biggest L. monocytogenes collection in diversity and quantity for characterization of the L. monocytogenes QAC tolerance at both phenotypic and genomic levels. IMPORTANCEContamination of Listeria monocytogenes within the food processing environment is of concern to the food industry due to challenges in eradicating the pathogen once it becomes persistent in the environment. Genetic markers associated with increased tolerance to disinfectants have been identified, which alongside factors favor the persistence of L. monocytogenes in the production environment. By employing a comprehensive large-scale phenotypic testing and genomic analysis our study significantly enhances the understanding of the prevalence of quaternary ammonium compound (QAC) tolerant L. monocytogenes and the genetic determinants associated with the increased tolerance. Furthermore, we report on the prevalence of QAC tolerance genes among 37,897 publicly available L. monocytogenes sequences and their distribution within clonal complexes, isolation sources and geographical locations. As the propagation of QAC tolerance showed not be evenly distributed globally this highlights that understanding the development of L. monocytogenes disinfectant tolerance can be monitored using publicly available WGS data.

microbiology↗

bioRxiv2023

iMOUSE - Reforming the Strategy of Refinement and Reduction for indispensable laboratory animal-based studies in translational research

Considering the intricate nature of biological processes within organisms, it is undeniable that relying solely on in vitro-generated primary-cell-like cultures or organ-like products in preclinical and basic research is insufficient to replace animal-based studies fully. This limitation is particularly significant when considering the regulations enforced by legislative assemblies worldwide. The necessity of animal-based studies to approve chemicals and medications. In contradiction, European countries aim to banish animal-based studies. Therefore, we must understand the impact of the data refinement and experiment replacement strategy we will introduce here. This project aimed to revolutionize data acquisition in animal-based studies by transforming manual observation into a reliable digital process. Reliable digital data will be generated by having the potential to reduce human bias by simply reducing human interaction. Additionally, reducing human interaction will reduce the severity levels due to stress reduction, fulfilling the 3R principles. Therefore, the first goal was to develop and implement a scalable, stable, running, and remotely accessible camera-based monitor system (the iMouse solution). At the same time, the target was to develop a retrofit solution (DigiFrame) for existing home-cage systems, not interfering with the regular workflow in animal facilities. As a result, we developed a digital monitoring system, named iMouseTV platform based on existing open-source software, allowing users to observe, record, share, and review animal-based studies within the home cage anytime from anywhere, reducing the stress level for the animals. Our systems first Proof of concept ran for over two years at the LIV in Hamburg. We also investigated an effective way to reduce data generation by setting up specific zones for detecting the motion of choice (e.g., drinking, food intake). The data sets can be stored, shared, and reviewed by users and refined by algorithms aiming to recognize the dedicated motions of the animals automatically. The implementation of the ML algorithms allows the iMouse solution to recognize whether an individual mouse was drinking and for how long and store results in the annotated video file and graph format. However, the identification and continuous tracking of the species is still in progress. In conclusion, we established a scalable human-independent monitoring and recording system, which can be implemented into the existing structures of institutions and companies without changing handling processes, to monitor animals and observe them by getting reliable digital data. Moreover, it is fundamental for automatic recognition within animal-based studies based on Artificial Intelligence.

animal behavior and cognition↗