Insight in lag phase of Listeria monocytogenes during enrichment through proteomic and transcriptomic responses.

The dynamics of the enrichment-based detection procedure of the foodborne pathogen Listeria monocytogenes from food still remains poorly understood. This enrichment is crucial in the reliable detection of this pathogen and more insight into the recovery mechanism during this step is important to advance our understanding of lag phase behaviour during enrichment. In this study we combined transcriptomic and proteomic analyses to better understand the physiological processes within the lag phase of L.

Heterogeneity in single-cell outgrowth of Listeria monocytogenes in half Fraser enrichment broth is affected by strain variability and physiological state.

The behaviour of pathogens at the single-cell level can be highly variable and can thus affect the detection efficacy of enrichment-based detection methods. The outgrowth of single cells of three Listeria monocytogenes strains was monitored after fluorescence-activated single-cell sorting in non-selective brain heart infusion (BHI) broth and selective half Fraser enrichment broth (HFB) to quantify outgrowth heterogeneity and its effect on the detection probability. Single-cell heterogeneity was higher in HFB compared to non-selective BHI and heterogeneity increased further when cells were heat-stressed.

Variability in lag duration of Listeria monocytogenes strains in half Fraser enrichment broth after stress affects the detection efficacy using the ISO 11290-1 method.

A collection of 23 Listeria monocytogenes strains of clinical and food origin was tested for their ability to recover and grow out in half Fraser enrichment broth following the ISO 11290-1:2017 protocol. Recovery of sub-lethally heat-injured cells in half Fraser broth was compared to reference cells with no stress pre-treatment. The enrichments were followed over time by plate counts and the growth parameters were estimated with the 3-phase model which described the data best.

Cas3-Derived Target DNA Degradation Fragments Fuel Primed CRISPR Adaptation.

Prokaryotes use a mechanism called priming to update their CRISPR immunological memory to rapidly counter revisiting, mutated viruses, and plasmids. Here we have determined how new spacers are produced and selected for integration into the CRISPR array during priming. We show that Cas3 couples CRISPR interference to adaptation by producing DNA breakdown products that fuel the spacer integration process in a two-step, PAM-associated manner.

[Quality of a non-subsidised multicentre randomised trial in non-academic hospitals; an audit].

Objective: To determine whether a randomised clinical trial in general hospitals can be performed in a reliable way without financial support.

Design: Descriptive.

Method: The trial involved 1040 patients in whom an inguinal hernia had been corrected with a propylene mat in the period 1998-2003.