Effect of osmotic stress and culture density on invasiveness of Listeria monocytogenes strains
Ewa Wałecka-Zacharska , Jerzy Molenda , Renata Karpíšková , Jacek Bania
AbstractThe effect of osmotic stress on its capacity to invade the human enterocytic cell line HT-29 was studied inthe early log through the stationary phase in 10L. monocytogenesstrains representing three geneticallyindependent lineages. The results demonstrate that the transition of the bacteria from the log to the stationaryphase results in a stepwise reduction of invasiveness. This effect was heterogeneous in the studiedL. monocytogenespopulation, as the range of invasiveness reduction between the log and stationary phasesvaried from 10- to 380-fold depending on the strain. Ten-minute exposure to 0.3 M NaCl was sufficient togenerate invasiveness alteration. No significant change in invasiveness induction caused by osmotic stresswas found between the different points of the log phase (OD6000.4–1.2), being significantly different in theearly log phase (OD6000.2–0.3) and in the stationary phase after 18 h of culture. The level of internalinsandopuCAtranscripts in response to osmotic stress did not correlate with invasiveness alteration in mostL. monocytogenesstrains.Prolongation of stress exposure to 1 h and an increase in NaCl concentration from 0.3 to 1.8 M had nosignificant effect on a further increase in invasiveness. Short exposure times and low NaCl concentrationswere sufficient for the generation of maximal invasiveness response ofL. monocytogenes. It appears thatalthough stationary-phase bacteria exhibit lower invasiveness than log-phase bacteria, they have a greatercapacity to enhance their pathogenicity in response to stress.
|Journal series||International Journal of Food Microbiology, ISSN 0168-1605, e-ISSN 1879-3460, (A 40 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||Listeria monocytogenes, Osmotic stress, Growth phase, Plaque forming, Invasiveness|
|ASJC Classification||; ;|
|Publication indicators||= 12; : 2011 = 1.711; : 2011 = 3.327 (2) - 2011=3.847 (5)|
|Citation count*||19 (2020-08-02)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.