How Manure from Antibiotic-Treated Cattle Affects Soil Microbes

Jenn Hoskins
22nd March, 2024

Key Findings

Virginia Tech study shows soil type and moisture level affect how soil microbes react to antibiotic-laden manure
Antibiotics in manure can change soil microbes and nitrogen levels, but effects vary with soil conditions
Findings suggest tailored manure management could help combat soil antibiotic resistance

Antibiotic resistance is a growing threat to global health, with the potential to render common infections untreatable and complicate medical procedures. One area of concern is the persistence of antibiotic resistance genes (ARGs) in soil environments, particularly in agricultural settings where antibiotics are used in livestock production. The introduction of manure from antibiotic-treated cattle into soil ecosystems can have profound effects on the microbial communities that are key to soil health and function. A recent study conducted by researchers at Virginia Tech^[1] has shed light on how different soil types and moisture levels can influence the way soil microbial communities respond to manure from cattle treated with antibiotics. The study's findings are crucial for developing strategies to manage antibiotic resistance in soil systems. The researchers set up soil microcosms—controlled mini-ecosystems that replicate natural soil environments—using two distinct soil types and varying moisture levels (15%, 30%, or 45%). Over the course of the experiment, these microcosms received biweekly additions of manure from cattle that had been given either cephapirin or pirlimycin, two common antibiotics, as well as manure from cattle that had not been treated with antibiotics, or no manure at all. Analysis revealed that while the type of soil and its moisture content were the most significant factors in determining the structure of soil microbiomes, the addition of antibiotic-laden manure also had noticeable effects. For instance, the study observed changes in the abundance of individual ARGs and shifts in the overall community structure of microbes in the soil. Interestingly, the activity of the microbial communities, as measured by soil respiration rates, increased with cephapirin treatment but decreased when pirlimycin was used. Additionally, the presence of manure from antibiotic-treated cattle influenced soil nitrogen cycling, a crucial process for plant growth and ecosystem health. Specifically, there was an increase in ammonium (NH4+) and a decrease in nitrate (NO3-) availability in certain conditions, although these effects were strongly dependent on the type of soil and its moisture content. These findings are significant when considered in the context of previous research. For example, a study in Hainan, China, found a high abundance and diversity of ARGs in mangrove sediments, which were positively correlated with mobile genetic elements, suggesting potential for ARG spread^[2]. Similarly, manure from antibiotic-treated cattle has been shown to alter microbial community structure and functional processes such as carbon and nitrogen cycling in soil ecosystems^[3]. Furthermore, the influence of environmental factors such as moisture and temperature on microbial communities has been previously documented^[4]. These factors can affect how microbial populations with potential for growth respond to external disturbances, which aligns with the Virginia Tech study's findings on the role of soil type and moisture in modulating the impact of antibiotics on soil microbiomes. The effects of antibiotics on soil nitrogen transformations and microbial communities have also been investigated under different redox conditions, with results indicating that antibiotics can inhibit nitrite reduction during the denitrification process and cause temporal changes in microbial community composition^[5]. The Virginia Tech study builds upon these earlier findings by demonstrating that the response of soil microbial communities to antibiotic exposure is not uniform; it is heavily influenced by the environmental context. This insight is vital for agricultural management practices, as it suggests that a one-size-fits-all approach to the application of manure from antibiotic-treated cattle may not be effective. Instead, a more nuanced strategy that takes into account the specific soil type and moisture conditions of a given agricultural field could lead to better management of antibiotic resistance in soil ecosystems. In conclusion, the study from Virginia Tech emphasizes the complexity of interactions between antibiotics, soil, and microbial communities. It highlights the need for more refined management practices that consider environmental variability to mitigate the spread of antibiotic resistance in agricultural soils. The integration of such research findings into agricultural policy and practice could play a significant role in addressing the global antimicrobial resistance crisis.

Environment Ecology Agriculture

References

Main Study

1) Soil type and moisture content alter soil microbial responses to manure from cattle administered antibiotics.

Published 20th March, 2024

https://doi.org/10.1007/s11356-024-32903-z

Related Studies

2) Diverse and abundant antibiotic resistance genes in mangrove area and their relationship with bacterial communities - A study in Hainan Island, China.

https://doi.org/10.1016/j.envpol.2021.116704

3) Prolonged exposure to manure from livestock-administered antibiotics decreases ecosystem carbon-use efficiency and alters nitrogen cycling.

https://doi.org/10.1111/ele.13390

4) Moisture Is More Important than Temperature for Assembly of Both Potentially Active and Whole Prokaryotic Communities in Subtropical Grassland.

https://doi.org/10.1007/s00248-018-1310-1

5) Environmental fate and microbial effects of monensin, lincomycin, and sulfamethazine residues in soil.

https://doi.org/10.1016/j.envpol.2018.11.093

Key Findings

References

Main Study

Related Studies

Related Articles