National Food Institute, Technical University of Denmark, Søltofts Plads, Bldg 221, DK-2800 Kongens Lyngby, Denmark.
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, DK-1870 Frederiksberg C, Denmark.
J Med Microbiol. 2013 Dec;62(Pt 12):1799-1806. doi: 10.1099/jmm.0.057505-0. Epub 2013 Sep 6.
Listeria monocytogenes is an important food-borne bacterial pathogen and listeriosis can result in abortions in pregnant women. The bacterium can colonize food-processing environments, where specific molecular subtypes can persist for years. The purpose of this study was to determine the virulence potential of a group of food-processing persistent L. monocytogenes strains encoding a premature stop codon in inlA (encoding internalin A) by using two orally dosed models, pregnant mice and pregnant guinea pigs. A food-processing persistent strain of L. monocytogenes invaded placentas (n = 58; 10 % positive) and fetuses (3 % positive) of pregnant mice (n = 9 animals per strain), similar to a genetically manipulated murinized strain, EGD-e InlA(m*) (n = 61; 3 and 2 %, respectively). In pregnant guinea pigs (n = 9 animals per bacterial strain), a maternofetal strain (from a human fetal clinical fatal case) was isolated from 34 % of placenta samples (n = 50), whereas both food-processing persistent strains were found in 5 % of placenta samples (n = 36 or 37). One of the food-processing persistent strains, N53-1, was found in up to 8 % of guinea pig fetal liver and brain samples, whereas the maternofetal control was found in 6 % of fetal tissue samples. As the food-processing persistent strains carry a premature stop codon in inlA but are invasive in orally dosed pregnant mice and guinea pigs, we hypothesize that listerial crossing of the placental barrier can occur by a mechanism that is independent of an interaction between E-cadherin and InlA.
李斯特菌 monocytogenes 是一种重要的食源性病原体，可导致孕妇流产。该细菌可定植于食品加工环境中，某些特定的分子亚型可在该环境中持续存在多年。本研究旨在通过使用两种口服给药模型，即怀孕小鼠和怀孕豚鼠，确定一组编码内部素 A （编码内毒素 A ）过早终止密码子的食品加工持续性李斯特菌菌株的毒力潜能。食品加工持续性李斯特菌菌株可侵袭怀孕小鼠的胎盘（n = 58；10 ％阳性）和胎儿（3 ％阳性）（每株 9 只动物），类似于遗传修饰的鼠化菌株 EGD-e InlA （m*）（分别为 3 ％和 2 ％阳性）。在怀孕豚鼠（每株细菌 9 只动物）中，母体 - 胎儿菌株（来自人类胎儿临床致命病例）从 34 ％的胎盘样本（n = 50）中分离出来，而两种食品加工持续性菌株均从 5 ％的胎盘样本中分离出来（n = 36 或 37）。食品加工持续性菌株 N53-1 可在高达 8 ％的豚鼠胎肝和脑组织样本中发现，而母体 - 胎儿对照株则在 6 ％的胎组织样本中发现。由于食品加工持续性菌株在 inlA 中携带过早终止密码子，但可侵袭口服给予的怀孕小鼠和豚鼠，我们假设李斯特菌穿过胎盘屏障的机制可能不依赖于 E-钙粘蛋白和 InlA 之间的相互作用。
