The Response to Oxidative Stress in Listeria monocytogenes Is Temperature Dependent

Abstract

The stress response of 11 strains of Listeria monocytogenes to oxidative stress was studied. The strains included ST1, ST5, ST7, ST6, ST9, ST87, ST199 and ST321 and were isolated from diverse food processing environments (a meat factory, a dairy plant and a seafood company) and sample types (floor, wall, drain, boxes, food products and water machine). Isolates were exposed to two oxidizing agents: 13.8 mM cumene hydroperoxide (CHP) and 100 mM hydrogen peroxide (H2O2) at 10 °C and 37 °C. Temperature affected the oxidative stress response as cells treated at 10 °C survived better than those treated at 37 °C. H2O2 at 37 °C was the condition tested resulting in poorest L. monocytogenes survival. Strains belonging to STs of Lineage I (ST5, ST6, ST87, ST1) were more resistant to oxidative stress than those of Lineage II (ST7, ST9, ST199 and ST321), with the exception of ST7 that showed tolerance to H2O2 at 10 °C. Isolates of each ST5 and ST9 from different food industry origins showed differences in oxidative stress response. The gene expression of two relevant virulence (hly) and stress (clpC) genes was studied in representative isolates in the stressful conditions. hly and clpC were upregulated during oxidative stress at low temperature. Our results indicate that conditions prevalent in food industries may allow L. monocytogenes to develop survival strategies: these include activating molecular mechanisms based on cross protection that can promote virulence, possibly increasing the risk of virulent strains persisting in food processing plants.

NtrC, The Master Regulator Controls the Utilization of Alternative Nitrogen Sources in Pseudomonas Stutzeri A1501

“…The phenotype of the ntrC mutant indicated that NtrC was not only absolutely required for nitrogen metabolism in P. stutzeri, but also related to optimal resistance to oxidative stress. The ntrC mutant showed signi cant upregulation of oxidative stress response genes, especially katB, which is the most pivotal enzyme for oxidizing agent CHP (Manso et al 2020). Bioinformatics analysis revealed one NtrC binding site to the promoter region of katB, indicating that KatB is the potential target regulated by NtrC.…”

Antibiofilm Effects of Nanoparticles and Visible Light Illumination Against Listeria monocytogenes

“…Well-established L. monocytogenes ATCC 7644 strain was chosen to enable international comparison of results between studies. Research by Manso et al (2020) showed that different Listeria monocytogenes isolates differ in susceptibility for environmental stress; therefore, other listeria strains should be further investigated in the future to accomplish knowledge how different strains react to nanomaterials and illumination.…”

Adaptive Response of Listeria monocytogenes to the Stress Factors in the Food Processing Environment

“…In order to withstand exposure to oxidizing agents, e.g., sodium hypochlorite, cells must activate mechanisms to repair damages of proteins, the cytoplasmic membrane, and nucleic acids. Listeria monocytogenes under oxidative stress activates a survival strategy that includes the expression of sigB , cold and heat shock proteins, proteases (ClpC, ClpP, and GroEL), and ROS detoxification systems ( Manso et al, 2020 ). ROS detoxification systems include superoxide dismutase (Sod), catalase (Kat), and alkylhydroperoxidase (AhpCF; Bucur et al, 2018 ).…”

“… Manso et al (2020) have shown that oxidative stress is temperature-dependent. The lower temperature increased oxidative stress response.…”

“…The lower temperature increased oxidative stress response. Both stressful conditions caused similar damage to nucleic acids and cell membranes ( Manso et al, 2020 ). Most of the disinfectants used in the food industry are applied at low temperatures, favoring the acquisition of resistance by L. monocytogenes .…”