Academic Journal

Composting dairy cattle manure significantly reduces antibiotic-resistant bacteria with no biochar impact.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος: Composting dairy cattle manure significantly reduces antibiotic-resistant bacteria with no biochar impact.
Συγγραφείς: Agga GE; Food Animal Environmental Systems Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Bowling Green, Kentucky, USA., Netthisinghe A; Department of Agriculture and Food Science, Western Kentucky University, Bowling Green, Kentucky, USA., Woosley P; Department of Agriculture and Food Science, Western Kentucky University, Bowling Green, Kentucky, USA., Strunk W; Department of Agriculture and Food Science, Western Kentucky University, Bowling Green, Kentucky, USA., Sistani KR; Food Animal Environmental Systems Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Bowling Green, Kentucky, USA.
Πηγή: Applied and environmental microbiology [Appl Environ Microbiol] 2026 Sep 23; Vol. 92 (9), pp. e0125826. Date of Electronic Publication: 2026 Aug 13.
Τύπος έκδοσης: Journal Article
Γλώσσα: English
Στοιχεία περιοδικού: Publisher: American Society for Microbiology Country of Publication: United States NLM ID: 7605801 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1098-5336 (Electronic) Linking ISSN: 00992240 NLM ISO Abbreviation: Appl Environ Microbiol Subsets: MEDLINE
Imprint Name(s): Original Publication: Washington, American Society for Microbiology.
Ιατρικοί όροι (MeSH): Manure*/microbiology , Composting*/methods , Escherichia coli*/drug effects , Escherichia coli*/isolation & purification , Escherichia coli*/genetics , Enterococcus*/drug effects , Enterococcus*/isolation & purification , Enterococcus*/genetics , Charcoal* , Drug Resistance, Bacterial*, Anti-Bacterial Agents/pharmacology ; Animals ; Cattle ; Dairying
Περίληψη: In two randomized controlled field studies, we investigated the effect of biochar-amended dairy manure composting on the concentrations and prevalence of generic and antibiotic-resistant E. coli and enterococci. Fresh dairy manure mixed with sawdust and biochar was randomly distributed into plastic reactors and composted for 6 months. Pre-compost (biochar, sawdust, fresh dairy manure), manure mixture, and final compost samples were cultured for enumeration and prevalence. While biochar and sawdust were not significant sources, fresh dairy manure was the major contributor of bacteria to the initial manure mixture. Biochar amendment did not significantly reduce bacterial load beyond that could be achieved by composting alone. Spring-summer composting was more effective than fall-winter composting. While E. coli was more prone, enterococci were more likely to survive composting. Dairy manure composting eliminated bacteria (3rd generation cephalosporin-resistant [3GCr] and extended spectrum beta-lactamase-producing [ESBL]-E. coli) resistant to critically important and highest priority antibiotics for human health and significantly reduced the prevalence and concentrations of other investigated bacteria. 3GCr- and ESBL-E. coli from fresh dairy manure were multidrug resistant and carried blaCTX-M genes, a widely distributed ESBL gene type. By whole-genome sequencing, ESBL-E. coli from experiment 1 (fall-winter) had diverse resistance profiles, sequence types, plasmid profiles, virulence factor genes, and more blaCTX-M genes (CTX-M-1, CTX-M-32, and CTX-M-55). However, those from experiment 2 (spring-summer) were clonal and carried blaCTX-M-55 only. In conclusion, dairy manure composting effectively removes antibiotic resistant bacteria of public health importance, with no added effect of biochar amendment.
Importance: Composting is a microbially mediated decomposition of organic matter into a nutrient-rich product for use as fertilizer. Biochar, obtained from the pyrolysis of biomass including animal manure, has been used for soil amendment. Beyond its nutrient stabilizing potential, composting has been shown to reduce bacterial load in animal manure. However, its effect with or without a biochar addition was not evaluated under a randomized controlled field trial. Biochar was nearly bacteriologically "sterile," and the sawdust used as a bulking agent had low concentrations of innocuous bacteria indicating that dairy manure was the main source of bacteria to the pre-compost mixture. Biochar did not have an extra effect on the bacterial load beyond composting alone. Composting during spring/summer is more effective than fall/winter. Furthermore, it is more effective against gram-negatives than gram-positive bacteria. Importantly, composting effectively eliminated multidrug-resistant bacteria of critical importance to public health for safer use of dairy manure.
Competing Interests: The authors declare no conflict of interest.
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Grant Information: 5040-12630-007-000-D USDA; 5040-12630-007-041-A USDA
Contributed Indexing: Keywords: 3GCr; ESBL; antimicrobial resistance; biochar; composting; manure
Substance Nomenclature: 0 (Manure)
16291-96-6 (Charcoal)
0 (biochar)
0 (Anti-Bacterial Agents)
Entry Date(s): Date Created: 20260813 Date Completed: 20260923 Latest Revision: 20260925
Update Code: 20260925
PubMed Central ID: PMC13599537
DOI: 10.1128/aem.01258-26
PMID: 42593128
Βάση Δεδομένων: MEDLINE
Περιγραφή
ISSN:1098-5336
DOI:10.1128/aem.01258-26