Deng Shu-Xuan, Cheng An-Chun, Wang Ming-Shu, Cao Ping, Yan Bin, Yin Nian-Chun, Cao Sheng-Yan, Zhang Zhen-Hua
Avian Diseases Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Yaan 625014, Sichuan Province, China.
World J Gastroenterol. 2008 Feb 7;14(5):782-9. doi: 10.3748/wjg.14.782.
To identify and understand the regular distribution pattern for Salmonella enteritidis (S. enteritidis) in the internal organs of mice after an oral challenge over a 3 wk period.
Assays based on the serovar-specific DNA sequence of S. enteritidis from GenBank, and a serovar-specific real-time, fluorescence-based quantitative polymerase chain reaction (FQ-PCR) were developed for the detection of S. enteritidis. We used this assay to detect genomic DNA of S. enteritidis in the blood and the internal organs, including heart, liver, spleen, kidney, pancreas, and gallbladder, from mice after oral challenge at different time points respectively.
The results showed that the spleen was positive at 12 h post inoculation (PI), and the blood was at 14 h PI. The organism was detected in the liver and heart at 16 h PI, the pancreas was positive at 20 h PI, and the final organs to show positive results were the kidney and gallbladder at 22 h PI. The copy number of S. enteritidis DNA in each tissue reached a peak at 24-36 h PI, with the liver and spleen containing high concentrations of S. enteritidis, whereas the blood, heart, kidney, pancreas, and gallbladder had low concentrations. S. enteritidis populations began to decrease and were not detectable at 3 d PI, but were still present up to 12 d PI in the gallbladder, 2 wk for the liver, and 3 wk for the spleen without causing apparent symptoms.
The results provided significant data for understanding the life cycle of S. enteritidis in the internal organs, and showed that the liver and spleen may be the primary sites for setting itself up as a commensa over a long time after oral challenge. Interestingly, it may be the first time reported that the gallbladder is a site of carriage for S. enteritidis over a 12 d period. This study will help to understand the mechanisms of action of S. enteritidis infection in vivo.
确定并了解肠炎沙门氏菌（肠炎沙门菌）在经口感染小鼠3周内其在内脏器官中的分布规律。
基于GenBank中肠炎沙门菌的血清型特异性DNA序列，开发了一种血清型特异性实时荧光定量聚合酶链反应（FQ-PCR）检测方法用于检测肠炎沙门菌。我们使用该检测方法分别在不同时间点检测经口感染小鼠的血液及包括心脏、肝脏、脾脏、肾脏、胰腺和胆囊在内的内脏器官中肠炎沙门菌的基因组DNA。
结果显示，接种后12小时脾脏呈阳性，血液在接种后14小时呈阳性。接种后16小时在肝脏和心脏中检测到该菌，胰腺在接种后20小时呈阳性，最后显示阳性结果的器官是肾脏和胆囊，在接种后22小时呈阳性。每个组织中肠炎沙门菌DNA的拷贝数在接种后24 - 36小时达到峰值，肝脏和脾脏中含有高浓度的肠炎沙门菌，而血液、心脏、肾脏、胰腺和胆囊中的浓度较低。肠炎沙门菌数量开始减少，在接种后3天无法检测到，但在胆囊中直至接种后12天仍存在，在肝脏中持续2周，在脾脏中持续3周，且未引起明显症状。
这些结果为了解肠炎沙门菌在内脏器官中的生命周期提供了重要数据，并表明肝脏和脾脏可能是经口感染后长时间内其作为共生菌定植的主要部位。有趣的是，这可能是首次报道胆囊是肠炎沙门菌长达12天的携带部位。本研究将有助于了解肠炎沙门菌体内感染的作用机制。
