Williams Denita, Irvin Elizabeth A, Chmielewski Revis A, Frank Joseph F, Smith Mary A
Department of Environmental Health Science, University of Georgia, Athens, Georgia 30602, USA.
J Food Prot. 2007 May;70(5):1122-8. doi: 10.4315/0362-028x-70.5.1122.
Listeriosis, a severe disease that results from exposure to the foodborne pathogen Listeria monocytogenes, is responsible for approximately 2500 illnesses and 500 deaths in the United States each year. Pregnant women are 20 times more likely to develop listeriosis than the general population, with adverse pregnancy outcomes that include spontaneous abortions, stillbirths, and neonatal meningitis. The objective of this study was to determine an infective dose that resulted in stillbirths and infectivity of selected tissues in pregnant guinea pigs. Pregnant guinea pigs were exposed orally on gestation day 35 to 10(4) to 10(8) L. monocytogenes CFU in sterile whipping cream. L. monocytogenes was recovered at 64, 73, 90, and 100% from the livers of animals infected with 10(5), 10(6), 10(7), and 10(8) CFU, respectively. In dams exposed to > or =10(6) CFU, L. monocytogenes was cultured from 50% of the spleen samples and 33% of the gallbladder samples. Eleven of 34 dams infected with > or =10(6) CFU delivered stillborn pups. L. monocytogenes was cultured from the placenta, liver, and brain tissue of all stillbirths. Dams that delivered nonviable fetuses after treatment with > or =10(7) L. monocytogenes CFU had fecal samples positive for L. monocytogenes at every collection posttreatment. On the basis of a log-logistic model, the dose that adversely affected 50% of the pregnancies was approximately 10(7) L. monocytogenes CFU compared with that estimated from a human outbreak of 106 CFU. Listeriosis in pregnant guinea pigs can result in stillbirths, and the overall disease is similar to that described in nonhuman primates and in humans.
李氏杆菌病是一种因接触食源性病原体单核细胞增生李斯特菌而引发的严重疾病，在美国每年约导致2500例患病和500例死亡。孕妇感染李氏杆菌病的可能性比普通人群高20倍，会出现包括自然流产、死产和新生儿脑膜炎等不良妊娠结局。本研究的目的是确定导致怀孕豚鼠死产的感染剂量以及所选组织的感染性。怀孕豚鼠在妊娠第35天经口暴露于无菌搅打奶油中含10⁴至10⁸CFU的单核细胞增生李斯特菌。分别从感染10⁵、10⁶、10⁷和10⁸CFU的动物肝脏中回收单核细胞增生李斯特菌的比例为64%、73%、90%和100%。在暴露于≥10⁶CFU的母鼠中，50%的脾脏样本和33%的胆囊样本培养出单核细胞增生李斯特菌。34只感染≥10⁶CFU的母鼠中有11只产出死胎。所有死胎的胎盘、肝脏和脑组织均培养出单核细胞增生李斯特菌。用≥10⁷CFU单核细胞增生李斯特菌处理后产出无法存活胎儿的母鼠，在每次处理后的粪便样本中单核细胞增生李斯特菌均呈阳性。基于对数逻辑模型，对50%的妊娠产生不利影响的剂量约为10⁷CFU单核细胞增生李斯特菌，而从一次人类疫情估计的剂量为10⁶CFU。怀孕豚鼠的李氏杆菌病可导致死产，总体疾病情况与非人灵长类动物和人类中描述的相似。
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