Research and Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
Asymmetric Operations Sector, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
Mil Med. 2024 Jul 3;189(7-8):e1753-e1759. doi: 10.1093/milmed/usad488.
Military trainees are at increased risk for infectious disease outbreaks because of the unique circumstances of the training environment (e.g., close proximity areas and physiologic/psychologic stress). Standard medical countermeasures in military training settings include routine immunization (e.g., influenza and adenovirus) as well as chemoprophylaxis [e.g., benzathine penicillin G (Bicillin) for the prevention of group A streptococcal disease] for pathogens associated with outbreaks in these settings. In a population of U.S. Army Infantry trainees, we evaluated changes in the oral microbiome during a 14-week military training cycle.
Trainees were enrolled in an observational cohort study in 2015-2016. In 2015, Bicillin was administered to trainees to ameliorate the risk of group A Streptococcus outbreaks, whereas in 2016, trainees did not receive a Bicillin inoculation. Oropharyngeal swabs were collected from participants at days 0, 7, 14, 28, 56, and 90 of training. Swabs were collected, flash frozen, and stored. DNA was extracted from swabs, and amplicon sequencing of the 16s rRNA gene was performed. Microbiome dynamics were evaluated using the QIIME 2 workflow along with DADA2, SINA with SILVA, and an additional processing in R.
We observed that microbiome samples from the baseline (day 0) visit were distinct from one another, whereas samples collected on day 14 exhibited significant microbiome convergence. Day 14 convergence was coincident with an increase in DNA sequences associated with Streptococcus, though there was not a significant difference between Streptococcus abundance over time between 2015 and 2016 (P = .07), suggesting that Bicillin prophylaxis did not significantly impact overall Streptococcus abundance.
The temporary convergence of microbiomes is coincident with a rise in communicable infections in this population. The dynamic response of microbiomes during initial military training supports similar observations in the literature of transient convergence of the human microbiome under cohabitation in the time frame including in this experiment. This population and the associated longitudinal studies allow for controlled studies of human microbiome under diverse conditions.
由于训练环境的特殊情况（例如，近距离区域和生理/心理压力），军事受训人员更容易发生传染病暴发。军事训练环境中的标准医疗对策包括常规免疫（例如，流感和腺病毒）以及化学预防措施[例如，苄星青霉素 G（西林）预防 A 组链球菌病]，以预防这些环境中的病原体暴发。在一组美国陆军步兵受训人员中，我们评估了在 14 周的军事训练周期中口腔微生物组的变化。
2015-2016 年，受训人员参加了一项观察性队列研究。2015 年，给受训人员使用西林来减轻 A 组链球菌暴发的风险，而在 2016 年，受训人员未接种西林。在训练的第 0、7、14、28、56 和 90 天，从参与者收集口咽拭子。收集拭子，快速冷冻并储存。从拭子中提取 DNA，并对 16s rRNA 基因进行扩增子测序。使用 QIIME 2 工作流程以及 DADA2、SINA with SILVA 以及 R 中的额外处理，评估微生物组动态。
我们观察到，基线（第 0 天）访问的微生物组样本彼此不同，而第 14 天采集的样本则表现出明显的微生物组趋同。第 14 天的趋同与链球菌相关的 DNA 序列增加同时发生，尽管 2015 年和 2016 年之间链球菌丰度没有显著差异（P=0.07），这表明西林预防措施并未显著影响链球菌的总体丰度。
在该人群中，微生物组的暂时趋同与传染性感染的增加同时发生。在这个人群中，微生物组在最初军事训练期间的动态反应支持了文献中在包括本实验时间范围内人类微生物组在同居下短暂趋同的类似观察。该人群及其相关的纵向研究允许在各种条件下对人类微生物组进行对照研究。
