Schlech W F, Chase D P, Badley A
Department of Medicine, Dalhousie University Faculty of Medicine, Halifax, Nova Scotia, Canada.
Int J Food Microbiol. 1993 Mar;18(1):15-24. doi: 10.1016/0168-1605(93)90003-y.
Recent epidemiological evidence suggests that Listeria monocytogenes (LM) is a food-borne pathogen in humans. A model of LM infection was developed using the Sprague-Dawley (SD) rat to study the interaction of LM with gastrointestinal epithelium as the first step in the pathogenesis of invasive listeriosis. Conventionally raised, juvenile female SD rats were given 10(2)-10(9) virulent L. monocytogenes, serotype 4b or nonpathogenic Listeria species. Only rats given virulent LM developed dose-dependent invasive infection of the liver and spleen. Light and electron microscopic studies suggested attachment to and invasion of the gastrointestinal mucosa by virulent LM. Because the development of invasive listeriosis in humans has been epidemiologically associated with a decrease in gastric acidity, the effect of decreasing gastric acidity on dose-dependent infection was studied. Rats were pretreated with cimetidine (50 mg/kg) by intraperitoneal injection prior to oral inoculation of 10(2)-10(9) virulent L. monocytogenes. Cimetidine significantly lowered the infective dose of virulent L. monocytogenes (P < 0.05). This oral model should allow further study of host and organism-specific virulence factors mediating the gastrointestinal phase of invasive LM infection, an increasingly important public health problem.
近期的流行病学证据表明，单核细胞增生李斯特菌（LM）是一种可导致人类食源性感染的病原体。为了研究LM与胃肠道上皮细胞的相互作用，以此作为侵袭性李斯特菌病发病机制的第一步，我们利用斯普拉格-道利（SD）大鼠建立了LM感染模型。将常规饲养的幼年雌性SD大鼠给予10² - 10⁹个毒力强的4b型单核细胞增生李斯特菌或非致病性李斯特菌属。只有给予毒力强的LM的大鼠才会发生剂量依赖性的肝脏和脾脏侵袭性感染。光学显微镜和电子显微镜研究表明，毒力强的LM会附着并侵入胃肠道黏膜。由于人类侵袭性李斯特菌病的发生在流行病学上与胃酸降低有关，因此研究了降低胃酸对剂量依赖性感染的影响。在口服接种10² - 10⁹个毒力强的单核细胞增生李斯特菌之前，通过腹腔注射用西咪替丁（50 mg/kg）对大鼠进行预处理。西咪替丁显著降低了毒力强的单核细胞增生李斯特菌的感染剂量（P < 0.05）。这种口服模型应有助于进一步研究介导侵袭性LM感染胃肠道阶段的宿主和生物体特异性毒力因子，这是一个日益重要的公共卫生问题。
