Impact of Military Training on Skin Microbiome
Study reveals how military exercises alter skin bacteria in soldiers.
― 7 min read
Table of Contents
- Background on Military Microbiome Studies
- Study Purpose
- Study Design and Participants
- Sample Collection Process
- DNA Extraction and Analysis
- Analyzing the Microbial Community
- Findings on Skin Microbiome
- Changes Over Time
- Effects of Environmental Factors
- Intra- and Inter-Individual Variation
- Implications and Conclusions
- Original Source
The skin is not just a protective barrier but also a home to many tiny living things called microorganisms, including bacteria, fungi, and viruses. Together, these microorganisms make up what is known as the skin microbiome. This community of microbes is important for keeping our skin healthy and preventing infections. Different parts of our skin-like dry areas, moist areas, and oily areas-support different types of microbes.
The type and number of microbes on our skin can change based on factors like moisture, temperature, and pH levels. Most of the bacteria on our skin belong to a few main groups. For example, there are groups known as Actinomycetota, Bacillota, Pseudomonadota, and Bacteroidota. Each area of skin has its own unique mix of these microbes, with some areas being more diverse than others.
Factors like our personal hygiene, lifestyle choices, the climate we live in, and where we are located can also change the makeup of our skin microbiome. For instance, we can pick up microbes from objects we touch, other people, pets, or even the air around us. Military personnel, especially, face unique conditions that can affect their Skin Microbiomes due to being in different Environments and having limited access to hygiene facilities. When these changes occur, they can affect skin health and make someone more likely to get infections.
Background on Military Microbiome Studies
Research on the microbiome has often concentrated on the gut, but the skin microbiome has not received as much attention. This is surprising since the skin is the body's largest organ and plays a key role in protecting us from the outside world. For military personnel, understanding how their skin microbiome changes is particularly important since they work in challenging conditions where they need to maintain both health and performance.
Previous research has shown how microbiomes can change over time and how different skin conditions affect them. However, there hasn’t been much investigation into how living and training together in military settings impacts the bacterial community on skin.
Study Purpose
In this study, we looked at how military field training affects the skin bacterial microbiome of Norwegian soldiers. We took skin samples from the hands and forearms of soldiers before, during, and after a 10-day field exercise. We wanted to see if the skin microbiome would change significantly during the exercise and if it would eventually return to its original state.
By understanding how the skin microbiome changes, we hope to get better ideas on how to maintain skin health under extreme conditions and develop strategies to avoid negative effects on the skin microbiome for military personnel and others in high-stress situations.
Study Design and Participants
The study involved Norwegian soldiers who took part in a NATO field exercise called “Cold Response” in March 2022. Before collecting samples, we made sure to get ethical approval and informed consent from all soldiers. The study involved three sampling rounds:
- Baseline: The day before the exercise started.
- Post exercise: At the end of the 10-day field exercise.
- Three weeks post exercise: After a three-week leave period following the exercise.
We collected samples from 19 healthy male soldiers aged 20 to 30, making sure none had taken antibiotics or had any skin diseases recently. Soldiers were told not to wash or use any skin products for 12 hours before sample collection to avoid contamination.
Sample Collection Process
We collected skin samples from both the hypothenar palms (the lower part of the palms) and the volar forearms (the front of the forearms) using special swabs. The process was done by trained instructors following the same procedures at a consistent location each time. For each subject, we swabbed both hands and forearms, pooled them together, and used sterile controls to ensure cleanliness. The samples were then transported in cold conditions to preserve them until deeper analysis could take place.
DNA Extraction and Analysis
Once at the lab, we extracted DNA from the skin samples using specific kits designed for this purpose. We also included controls to ensure the accuracy of our analysis. After extracting the DNA, we measured the amount of DNA and ensured it was enough for further testing.
We used a method called polymerase chain reaction (PCR) to amplify certain segments of the bacterial DNA. This is important for identifying the types of bacteria present. After amplifying the DNA, we sequenced it to gather detailed information about the microbial community.
Analyzing the Microbial Community
To ensure the quality of the data we gathered, we used various software tools to clean and analyze the sequencing data. This included filtering out low-quality readings and removing any contaminants that might have been introduced during the sampling or analysis processes.
Once we had high-quality data, we examined the Bacterial Diversity in the samples. We looked at both alpha diversity, which focuses on diversity within a single sample, and beta diversity, which looks at differences between samples. We used statistical methods to identify any significant changes in microbial composition over time and between different skin areas.
Findings on Skin Microbiome
Our findings revealed a total of 6863 unique bacterial sequences in the samples, belonging to many different species and groups. We noticed that the bacterial diversity was significantly different between the hands and forearms before the exercise began. The hands had a greater variety of microorganisms compared to the forearms, likely due to different exposures and conditions.
After the field exercise, we observed changes in the bacterial composition. In general, we found that the microbial community on the hands was more stable compared to the forearms. While the overall diversity of bacteria on the hands remained unchanged, the forearms showed an increase in bacterial diversity after the training exercise.
Changes Over Time
Throughout the study, the microbial community showed significant shifts after the exercise. On the forearms, we noted an increase in the range of different bacterial species present. This suggests that exposure to new environments during the training altered the bacterial balance on the skin.
Interestingly, when we examined samples taken three weeks after the exercise, we found that neither skin area had returned to its original bacterial composition. This indicates that the changes caused by the exercise were more long-lasting.
Effects of Environmental Factors
The exercise environment contributed to the changes we observed in the skin microbiome. Many of the different bacterial types that became more common during the exercise are typically found in environmental sources like soil and plants. This reinforces the idea that the outdoor conditions provided new bacteria that influenced the soldiers’ skin microbiomes.
Some bacteria typically found in healthy skin also increased in abundance during the exercise, possibly due to changes in sweat and skin moisture levels caused by physical activity. This highlights how environmental exposure not only brings in new microbes but can also affect the existing ones.
Intra- and Inter-Individual Variation
We examined how similar or different the skin microbiomes were among soldiers both within the same individual over time and between different individuals. Interestingly, we found that during the exercise, the microbiomes of soldiers became more alike, possibly due to shared living conditions and activities.
However, after the exercise period, the diversity between individuals increased, showing that soldiers’ microbiomes became more distinct again during the recovery phase. This suggests that while the exercise brought them together microbiologically, the return to regular life promoted more individual differences.
Implications and Conclusions
The results from this study shed light on how military training can significantly affect the skin microbiome. The unique conditions soldiers face during field Exercises can lead to changes in microbial populations that may impact skin health.
Since the microbiome plays a crucial role in defending against infections, understanding these changes is necessary for improving hygiene practices and health protocols for military personnel and others in similar high-stress environments.
Further research should focus on understanding the specific influences of various factors on the skin microbiome and how these changes might impact health outcomes. This knowledge could help enhance the well-being of soldiers and inform infection control and hygiene practices beyond military contexts.
In summary, this study provides valuable insights into how the skin microbiome can adapt to environmental challenges and highlights the importance of maintaining microbial health for overall well-being. Understanding these patterns, especially in demanding situations, can lead to better health strategies for both military personnel and the general population.
Title: Skin bacterial community dynamics of hands and forearms before and after military field exercise
Abstract: The human skin microbiome is crucial for skin health and immunity, especially in the context of extreme conditions faced by military personnel. Soldiers encounter unique stressors and hygienic challenges that can impact the microbial composition of their skin during field exercises and in regular occupational settings. In this study, we aimed to investigate the impact of a military field exercise on the diversity and composition of the skin bacterial microbiota using 16S rRNA sequencing. We conducted a longitudinal study during the NATO exercise Cold Response 2022, involving Norwegian soldiers (n = 19) engaged in outdoor training operations. Skin swabs were taken from soldiers hands and forearms directly before and after the 10-day winter field exercise, and following a 3-week post-exercise leave. Our results reveal hand and forearm-specific shifts in bacterial populations associated with the exercise, likely influenced by environmental exposure, reduced hygiene, and heightened social contact. Alpha diversity increased on forearms while remaining stable on hands, which appeared more resilient to perturbations. Both sites exhibited temporal changes in composition, with soil- and water-associated bacteria enriched post-exercise; most being transient on hands but more sustained on forearms. The soldiers microbiomes became more similar during the exercise, followed by divergence in the leave period. Neither skin site returned to original composition at follow-up, indicating that field exercises may have lasting effects on the microbiome. Our findings highlight the impact of outdoor exposure on microbial communities and suggest that resilience and stability differ between skin sites. ImportanceOptimizing soldier health and resilience is critical for maintaining military readiness and operational effectiveness. The skin, as the bodys first line of defense, is subjected to numerous challenges in military environments. Unique environmental and hygiene challenges can disrupt the skin microbiome and increase susceptibility to skin and soft tissue infections. This longitudinal research provides valuable insights into the effects of military service on the bacterial dynamics of the skin microbiome, but can also inform hygiene management and disease prevention in comparable situations.
Authors: Trine B Rounge, S. Glenna, E. Birkeland, R. J. S. Orr, G. Gilfillan, M. Dalland, O. A. Okstad, O. A. Voie
Last Update: Oct 30, 2024
Language: English
Source URL: https://www.biorxiv.org/content/10.1101/2024.10.29.620909
Source PDF: https://www.biorxiv.org/content/10.1101/2024.10.29.620909.full.pdf
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
Thank you to biorxiv for use of its open access interoperability.