Transcriptomic Analysis of the Adaptation of Listeria monocytogenes to Lagoon and Soil Matrices Associated with a Piggery Environment: Comparison of Expression Profiles

Abstract

Understanding how Listeria monocytogenes, the causative agent of listeriosis, adapts to the environment is crucial. Adaptation to new matrices requires regulation of gene expression. To determine how the pathogen adapts to lagoon effluent and soil, two matrices where L. monocytogenes has been isolated, we compared the transcriptomes of L. monocytogenes CIP 110868 20 min and 24 h after its transfer to effluent and soil extract. Results showed major variations in the transcriptome of L. monocytogenes in the lagoon effluent but only minor modifications in the soil. In both the lagoon effluent and in the soil, genes involved in mobility and chemotaxis and in the transport of carbohydrates were the most frequently represented in the set of genes with higher transcript levels, and genes with phage-related functions were the most represented in the set of genes with lower transcript levels. A modification of the cell envelop was only found in the lagoon environment. Finally, the differential analysis included a large proportion of regulators, regulons, and ncRNAs.

Metabolism of the Gram-Positive Bacterial Pathogen Listeria monocytogenes

“…Similarly, consistent with limited availability of amino acids, 15 genes of the regulon of CodY, a repressor of branched chain amino acid biosynthesis, were upregulated at all timepoints following instillation of L. monocytogenes into soil (37). In a follow up study with different soil, upregulation of PTS systems was also observed, including those for cellobiose, mannitol and maltose, among others (38). Finally, both of these studies observed repression of genes regulated by the master virulence regulator, PrfA, consistent with the longstanding observation that in the presence of PTS substrates PrfA expression is repressed (39).…”

Initial Transcriptomic Response and Adaption of Listeria monocytogenes to Desiccation on Food Grade Stainless Steel

“…Two formate transporters (lmo0593, lmo0912) and a fumarate reductase (lmo0355) were downregulated explained by the evidence of formate being a metabolic end product only seen during anaerobic growth (Romick et al, 1996). In line with the upregulation during desiccation of glutamine transporters, glnR (lmo1298), a glutamine synthase repressor (Vivant et al, 2017) was downregulated. The most downregulated gene (>13 fold) during desiccation were the predicted transcriptional regulator lmo2447 ( Table 3).…”

Sources and survival ofListeria monocytogeneson fresh, leafy produce

“…Entry to the soil also causes prfA to be downregulated, subsequently deactivating key virulence factors while genes involved with mobility, chemotaxis and the transport of carbohydrates are upregulated (Vivant et al . ).…”

“…SigB too plays an important role in soil survival-it regulates the stress response after L. monocytogenes entry to the soil allowing the bacteria to stop multiplying as a response to nutrient limitation, similar to entry to the stationary phase (Piveteau et al 2011). Entry to the soil also causes prfA to be downregulated, subsequently deactivating key virulence factors while genes involved with mobility, chemotaxis and the transport of carbohydrates are upregulated (Vivant et al 2017).…”