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Experimental aspiration pneumonia induced by human supragingival dental plaque in mice

人龈上牙菌斑诱发小鼠实验性吸入性肺炎

基本信息

批准号：
17592185
负责人：
NAGATA Emi
金额：
$ 2.24万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17592185/
关键词：
dental plaque aspiration pneumonia oral bacteria mouse ラット

项目摘要

Human dental plaque consists of a wide variety of microorganisms, some of which are believed to cause systemic infections, including aspiration pneumonia. To confirm this hypothesis experimentally, we examined the pneumonia-inducing ability of dental plaque in mice, the microbial features of the infectious locus produced by the plaque. Aliquots of a suspension of supragingival dental plaque containing 1 x 10^7 CFU of bacteria were delivered into the lower part of the trachea of mice. All mice exhibited signs of illness immediately after inoculation such as ruffled fur, labored respiration, and appeared waste. In total, 12 out of 18 mice (66.7%) died within 3 days after inoculation with dental plaque suspension. All the 3 human dental plaque samples tested induced pneumonia in mice. Bacterial cells were recovered from the lungs of all the mice that died, and the number was 4.44 ± 0.77 log_<10>CFU/mg of lung. From 5 out of 6 survived mice, bacterial cells were recovered from the lungs and the number was 0.38±0.38 log_<10>CFU/mg of lung. Various microbial species were recovered from infected lungs examined, and no characteristic bacterial distribution was observed both in the survived mice and the mice that died within 3 days after plaque inoculation. Representative isolates of Streptococcus oralis, Streptococcus intermedius and Gemella morbillorum recovered from lungs showed ability to induce pneumonia, respectively. These results suggest that human supragingival dental plaque is a source of the infectious pathogens that cause pneumonia.

人类牙菌斑由各种各样的微生物组成，其中一些被认为会引起全身感染，包括吸入性肺炎。为了在实验上证实这一假设，我们检测了牙菌斑在小鼠身上引发肺炎的能力，以及由牙菌斑产生的感染点的微生物特征。将含有1×10~(-7)CFU菌落的牙菌斑悬液等份注入小鼠气管下部。所有的小鼠在接种后立即表现出疾病的迹象，如皮毛皱折，呼吸困难，并出现虚弱。总体而言，18只小鼠中有12只(66.7%)在接种牙菌斑悬液后3天内死亡。3个人牙菌斑样本均进行了小鼠肺炎试验。所有死亡小鼠的肺组织中均可回收细菌细胞，细菌数为4.44±0.77个/mg肺组织。在存活的6只小鼠中，有5只从肺中回收细菌细胞，细菌数为0.38±0.38个/mg肺组织。接种空斑后3天内死亡的小鼠和存活小鼠的肺组织中均未观察到典型的细菌分布。从肺部分离到的口腔链球菌、中间链球菌和病原菌代表菌株分别具有诱发肺炎的能力。这些结果表明，人类牙龈上菌斑是导致肺炎的感染性病原体的来源。