Composting can reduce antimicrobial resistance in manure

A brief summary of the manuscript, Dissipation of Antimicrobial Resistance Determinants in Composted and Stockpiled Beef Cattle Manure by Xu et al. (2016)

Key Points:

  • Composting manure can reduce pathogen presence and antimicrobial residues in manure.
  • Composting efficacy in reducing antimicrobial residues in manure is associated with elevated temperatures within the composting process.
  • Stockpiling manure marginally reduce pathogen presence and antimicrobial residues in manure when compared to composting.


In large animal feeding operations, where many animals are living together the question of what to do with animal manure is an important one. Moreover, concerns about the potential for manure to act as a vehicle for the transmission of antibiotic-resistant bacteria or genes to agricultural soils or crops means that there is a growing interest in identifying methods to reduce resistant populations in manure.

Temperature changes during composting (a) and stockpiling (b) of beef cattle manure over 102 days. The treatments were: control, no antimicrobials added to the feed of the steers; CTC, chlortetracycline at 44 mg kg-1 feed; CRCSMZ, chlortetracycline and sulfamethazine, at 44 mg kg-1 feed; and TYL, tylosin at 11 mg kg-1 feed. Arrows indicate the dates when the compost windrows were turned. Photo credit Xu et al (2016).

The study’s goal was to compare the presence of antimicrobial-resistant genes in manure that had been either composted or stockpiled. Both methods are common ways to reduce manure volume and stabilize nutrients prior to spreading. In the study, beef cattle were given feed with or without added antibiotics, and then the manure produced was either composted or stockpiled for 102 days. The results showed that temperatures in the composted manure were consistently higher than the stockpiled manure capable of inactivating pathogens and potentially reducing the transfer of antimicrobial resistance genes. This is important because the majority of pathogens are rendered nonviable if exposed to temperatures higher than 55 C for extended periods of time. Inclusion of antimicrobials in diet did not increase most anti‐microbial resistance genes in manure and this could be related to the presence of these genes in the environment at the time of evaluations. The authors of the study concluded that composting may be more effective than stockpiling in reducing the introduction of antimicrobial resistance genes into the environment before land application of manure.

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Written by Eric Henning while an Undergraduate Researcher in the Dept. of Biological Systems Engineering, University of Nebraska. Reviewed by: Sid Thakur, North Carolina State University and Eduardo Gutierrez-Rodriguez, Colorado State University.

The scientific research summarized in this article was published as:

Xu, S., Sura, S., Zaheer, R., Wang, G., Smith, A., Cook, S., Olson, A.F., Cessna, A.J., Larney, F.J. and McAllister, T.A. (2016), Dissipation of Antimicrobial Resistance Determinants in Composted and Stockpiled Beef Cattle Manure. J. Environ. Qual., 45: 528-536.

This article presents the author’s interpretation of the published research for a general audience and should not be considered a reflection of the position or opinion of the researchers.