Naval Surface Warfare Center (Dahlgren Division), Dahlgren VA, USA.
Front Cell Infect Microbiol. 2012 Jun 28;2:87. doi: 10.3389/fcimb.2012.00087. eCollection 2012.
There is a need to better understand inhalational anthrax in relevant animal models. This understanding could aid risk assessment, help define therapeutic windows, and provide a better understanding of disease. The aim here was to characterize and quantify bacterial deposition and dissemination in rabbits following exposure to single high aerosol dose (> 100 LD(50)) of Bacillus anthracis (Ames) spores immediately following exposure through 36 h. The primary goal of collecting the data was to support investigators in developing computational models of inhalational anthrax disease. Rabbits were vaccinated prior to exposure with the human vaccine (Anthrax Vaccine Adsorbed, AVA) or were sham-vaccinated, and were then exposed in pairs (one sham and one AVA) so disease kinetics could be characterized in equally-dosed hosts where one group is fully protected and is able to clear the infection (AVA-vaccinated), while the other is susceptible to disease, in which case the bacteria are able to escape containment and replicate uncontrolled (sham-vaccinated rabbits). Between 4-5% of the presented aerosol dose was retained in the lung of sham- and AVA-vaccinated rabbits as measured by dilution plate analysis of homogenized lung tissue or bronchoalveolar lavage (BAL) fluid. After 6 and 36 h, >80% and >96%, respectively, of the deposited spores were no longer detected in BAL, with no detectable difference between sham- or AVA-vaccinated rabbits. Thereafter, differences between the two groups became noticeable. In sham-vaccinated rabbits the bacteria were detected in the tracheobronchial lymph nodes (TBLN) 12 h post-exposure and in the circulation at 24 h, a time point which was also associated with dramatic increases in vegetative CFU in the lung tissue of some animals. In all sham-vaccinated rabbits, bacteria increased in both TBLN and blood through 36 h at which point in time some rabbits succumbed to disease. In contrast, AVA-vaccinated rabbits showed small numbers of CFU in TBLN between 24 and 36 h post-exposure with small numbers of bacteria in the circulation only at 24 h post-exposure. These results characterize and quantify disease progression in naïve rabbits following aerosol administration of Ames spores which may be useful in a number of different research applications, including developing quantitative models of infection for use in human inhalational anthrax risk assessment.
需要更好地了解相关动物模型中的吸入性炭疽。这种理解可以帮助进行风险评估,帮助确定治疗窗口,并更好地了解疾病。这里的目的是在暴露后立即通过 36 小时,对暴露于单一大气溶胶剂量(> 100LD(50))炭疽芽孢杆菌(Ames)孢子的兔子进行细菌沉积和传播的特征和定量。收集数据的主要目的是支持研究人员开发吸入性炭疽病的计算模型。兔子在暴露前用人类疫苗(炭疽疫苗吸附剂,AVA)进行了疫苗接种或假疫苗接种,然后成对暴露(一个假疫苗和一个 AVA),以便在同样剂量的宿主中对疾病动力学进行特征描述,其中一组完全受到保护并能够清除感染(AVA 疫苗接种的兔子),而另一组则易患疾病,在这种情况下,细菌能够逃脱控制并不受控制地复制(假疫苗接种的兔子)。通过对肺组织或支气管肺泡灌洗液(BAL)的匀浆进行稀释平板分析,测量到 4-5%的气溶胶剂量保留在假疫苗和 AVA 疫苗接种的兔子的肺部中。暴露后 6 小时和 36 小时后,BAL 中分别有超过 80%和超过 96%的沉积孢子不再被检测到,假疫苗和 AVA 疫苗接种的兔子之间没有检测到差异。此后,两组之间的差异变得明显。在假疫苗接种的兔子中,细菌在暴露后 12 小时在气管支气管淋巴结(TBLN)中被检测到,在 24 小时时在血液中被检测到,这一时间点也与一些动物的肺部组织中植物 CFU 的急剧增加有关。在所有假疫苗接种的兔子中,TBLN 和血液中的细菌在 36 小时内持续增加,此时有些兔子死于疾病。相比之下,AVA 疫苗接种的兔子在暴露后 24 小时至 36 小时之间 TBLN 中的 CFU 数量很少,仅在暴露后 24 小时时血液中的细菌数量很少。这些结果描述和定量了在接受 Ames 孢子气溶胶给药后,天真兔子的疾病进展,这可能对许多不同的研究应用有用,包括开发用于人类吸入性炭疽风险评估的感染定量模型。