Project description:Expression profiling by microarray was used with a murine listeriosis model to better understand increased susceptibility of preterm neonates to infection. We used DNA microarray to identify genes that were differentially expressed in liver of adult and neonatal Balb/c mice after listeriosis infection. A murine listeriosis model was established. The methods for culturing and counting the Listeria monocytogenes (strain CNL 85/163) had been described in previous publications. The Listeria was injected intraperitoneally using a 1-mL U-100 insulin syringe with a 30 gauge needle. Doses of Listeria monocytogenes used were based on work by our laboratory showing that similar bacterial colony counts were obtained with 4.2 x 10^5 total Listeria per adult mouse and 150 Listeria per gram for 3 to 5 day old neonatal mice. In neonatal mice, great care was taken to void deep intraperitoneal injection towards the viscera, or across the central abdominal vessels. At specified time points, liver was removed upon animal sacrifice and immediately flash frozen in liquid nitrogen and stored at -80 degrees Centigrade. Three adult mice and three neonatal mice were used at each time point.
Project description:Listeria monocytogenes is the ubiquitous food-borne pathogen which causes listeriosis, a disease with a high mortality rate, mostly transmitted through contaminated ready-to-eat foods (EFSA, 2018). To better understand the systemic response of such microorganism exposed at three environmental factors (T, pH and NaCl), the proteome of a L. monocytogenes strain, which was isolated from a meat product (Coppa di testa) linked to a listeriosis outbreak occurred in Marche region (Italy) in 2016, was investigated in order to identify differences in its protein patterns.
Project description:Human listeriosis cases are due to the ingestion of contaminated foods with the pathogenic bacteria Listeria monocytogenes. The reduction of water availability in food workshops by decreasing the air relative humidity (RH) is one strategy to improve the control of bacterial contamination. This study aims to develop and implement an MSI approach on L. monocytogenes biofilms and proof of concept using a dehumidified stress condition. MSI allowed examining the distribution of low molecular weight proteins within the biofilms subjected to a dehumidification environment, mimicking the one present in a food workshop (10°C, 75% RH). Furthermore, a LC-MS/MS approach was made to link the dots between MSI and protein identification. Five identified proteins were assigned to registered MSI m/z, including two cold-shock proteins and a ligase involved in cell wall biogenesis.
Project description:This study will evaluate the safety and tolerability of a personalized live, attenuated, double-deleted Listeria monocytogenes (pLADD) treatment in adults with metastatic colorectal cancer.
Project description:Listeria monocytogenes is a common clinical pathogen primarily transmitted among humans and animals through contaminated food. Currently, the increasing prevalence of antibiotic resistance due to the misuse of antibiotics has become a significant problem, leaving both clinical medicine and agriculture with a lack of effective treatments for Listeria infections. Listeriolysin O (LLO), a virulence factor secreted by Listeria monocytogenes, is a key factor in its pathogenicity. Strains of Listeria monocytogenes lacking the LLO gene are non-pathogenic to humans and animals. Therefore, studying the molecular mechanisms of LLO degradation is of great practical significance for treating clinical infections caused by antibiotic-resistant Listeria. Additionally, it will provide a theoretical basis for developing new antimicrobial drugs. Since Listeria monocytogenes secretes LLO throughout its entire life cycle within the host cell, understanding the fate of LLO at different stages of infection is crucial for elucidating the pathogenic mechanisms of Listeria monocytogenes. It is already known that LLO secreted by Listeria within the phagosome can be degraded via the lysosomal pathway. However, the fate of LLO secreted by Listeria in the cytoplasm remains poorly understood. Based on our previous experimental data and relevant literature, we propose a novel hypothesis that the AP-2 complex targets and degrades LLO secreted by Listeria in the cytoplasm.
