COMPARISON OF INFECTIOUS DOSE OF LISTERIA-MONOCYTOGENES F5817 AS DETERMINED FOR NORMAL VERSUS COMPROMISED C57B1/6J MICE
COMPARISON OF INFECTIOUS DOSE OF LISTERIA-MONOCYTOGENES F5817 AS DETERMINED FOR NORMAL VERSUS COMPROMISED C57B1/6J MICE
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DOI：
10.4315/0362-028x-52.10.696
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发表时间：
1989-10-01
影响因子：
2
通讯作者：
HOWARD, DB
中科院分区：
文献类型：
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作者：
GOLNAZARIAN, CA;DONNELLY, CW;HOWARD, DB
用正常和致弱的C57BL/6J小鼠口服感染4b型人单核细胞增多性李斯特氏菌F5817，测定其感染量。为了模仿先前被证明有摄入单核细胞增多性李斯特氏菌风险的人类群体，本研究使用的小鼠群体包括：经醋酸氢化可的松或西咪替丁预处理的小鼠；怀孕小鼠(怀孕12-14天)；或C57BL/6J小鼠的米色突变体(单核细胞和粒细胞内溶酶体产生不足)。给小鼠灌胃不同水平的单核细胞增多性李斯特氏菌，悬浮在无菌的11%脱脂牛奶固体(NFMS)中。过期后，小鼠的脾、肝、肺和脑被无菌取出。器官接种在LPM琼脂上，菌落计数和生化确认为单核细胞增多性李斯特菌。如果从至少一个被检查的器官中发现了单核细胞增多性李斯特菌，小鼠就被认为是感染的。在正常耐药的C57BL/6J小鼠中，感染剂量(ID50)为3.24-4.55log10CFU。相比之下，感染前每天服用2.5 mg醋酸氢化可的松的小鼠的ID50降至0.41log10CFU(范围-1.91-2.74log10CFU)。感染前给予0.25醋酸氢化可的松，连续3天，其ID50与正常小鼠的计算结果相似。经计算，孕鼠的半数致死剂量为2.48log10CFU，与正常对照小鼠无显著差异。米色突变体和西咪替丁处理的小鼠的反应与正常对照组相当，ID50值分别为4.00和3.30log10CFU。
The infectious dose of Listeria monocytogenes F5817, a serotype 4b human patient isolate, was determined following oral challenge in normal and compromised C57Bl/6J mice. In an attempt to mimic human populations previously shown to be at risk to ingestion of L. monocytogenes, groups of mice used in this study consisted of the following: mice pretreated with hydrocortisone acetate or cimetidine; pregnant mice (12-14 d gestation); or beige mutants of C57Bl/6J mice (deficient in lysosome production within monocytes and granulocytes). Mice were gavaged with varying levels of L. monocytogenes suspended in sterile 11% non-fat milk solids (NFMS). Upon expiration, the spleen, liver, lung, and brain were aseptically removed from mice. Organs were plated on LPM agar, and colonies were enumerated and biochemically confirmed as L. monocytogenes. Mice were considered infected if L. monocytogenes was recovered from at least one of the examined organs. In normal resistant C57Bl/6J mice, the infectious dose50 (ID50) ranged from 3.24-4.55 log10 CFU. In comparison, the ID50 for mice treated with 2.5 mg hydrocortisone acetate/day for 3d prior to infection decreased to 0.41 log10 CFU (range-1.91-2.74 log10 CFU). Administration of 0.25 hydrocortisone acetate/day for 3d prior to infection resulted in an ID50 similar to that calculated for normal mice. The ID50 calculated for pregnant mice was 2.48 log10 CFU, a value not significantly different from that of normal control mice. The response of beige mutants and cimetidine treated mice was comparable to that of normal controls, with ID50 values of 4.00 and 3.30 log10 CFU, respectively.