Werbrouck Hadewig, Vermeulen An, Van Coillie Els, Messens Winy, Herman Lieve, Devlieghere Frank, Uyttendaele Mieke
Flemish Government, Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
Int J Food Microbiol. 2009 Aug 31;134(1-2):140-6. doi: 10.1016/j.ijfoodmicro.2009.03.022. Epub 2009 Apr 5.
The influence of food-related acid stress on the virulence capacity of Listeria monocytogenes was evaluated. The survival of acid-adapted and non-adapted L. monocytogenes cells during exposure to lethal concentrations of acetic acid was monitored. Also the effect of sublethal acid stress exposure on the expression levels of several virulence genes and on the capacity to invade Caco-2 cells was analyzed. Acid-adapted and non-adapted cells showed different acid tolerance response (ATR) patterns. Our data also demonstrate that pre-exposure to sublethal acid stress might lead to gadD2 induction. However, no correlation with the origin of the strain and with the ATR was noticed, indicating that probably other genes also could play an important role in this ATR mechanism. Additionally, our data showed that acid adaptation could influence the virulence capacity by regulating the expression levels of virulence genes. Moreover, the inlA expression data strongly correlated with the results of the in vitro invasion study. These results lead to the indication that low pH and acetic acid, used in minimally processed food products, might influence the virulence potential of L. monocytogenes.
评估了与食物相关的酸应激对单核细胞增生李斯特菌毒力的影响。监测了适应酸和未适应酸的单核细胞增生李斯特菌细胞在暴露于致死浓度乙酸期间的存活情况。还分析了亚致死酸应激暴露对几种毒力基因表达水平以及侵袭Caco-2细胞能力的影响。适应酸和未适应酸的细胞表现出不同的酸耐受反应（ATR）模式。我们的数据还表明，预先暴露于亚致死酸应激可能导致gadD2诱导。然而，未观察到与菌株来源和ATR的相关性，这表明可能其他基因在这种ATR机制中也起着重要作用。此外，我们的数据表明，酸适应可通过调节毒力基因的表达水平来影响毒力。而且，inlA表达数据与体外侵袭研究结果密切相关。这些结果表明，最低限度加工食品中使用的低pH值和乙酸可能会影响单核细胞增生李斯特菌的毒力潜力。
