Treated and untreated cows housed side by side in tie-stalls and their respective risk of harboring E. coli resistant to antimicrobials

• Published in: PloS one Vol. 19; no. 11; p. e0310431
• Main Authors: Köchle, Belinda, Bernier Gosselin, Véronique, Kaspar, Heike, Becker, Jens
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.11.2024; Public Library of Science (PLoS)
• Subjects: Agriculture; Animal lactation; Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Antimicrobial agents; Antimicrobial resistance; Bacteria; Biology and Life Sciences; Case-Control Studies; Cattle; Cattle Diseases - drug therapy; Cattle Diseases - microbiology; Coliforms; Dairy cattle; Dairy farming; Dairy farms; Dairying; Diseases; Drug resistance in microorganisms; Drug Resistance, Bacterial; E coli; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - isolation & purification; Escherichia coli infections; Escherichia coli Infections - drug therapy; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Farm management; Farmers; Farms; Female; Forage crops; Genetic aspects; Growth; Housing, Animal; International organizations; Laboratories; Medicine and Health Sciences; Microbial Sensitivity Tests; Postpartum period; Practice; Prevention; Research and Analysis Methods; Risk factors; Sample size; Veterinary medicine; Canada; Germany; Italy; Basel Switzerland; United States > US; Switzerland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0310431

Parenteral antimicrobial treatment results in the excretion of antimicrobial-resistant bacteria. Dairy cows are commonly housed side by side in tie-stalls and often receive antimicrobial treatment. However, studies investigating treated cows as source of colonization of neighboring cows with resistant bacteria are scarce. Antimicrobial resistance (AMR) in cows (treated and untreated) in tie-stalls was investigated to assess their respective risks of carrying resistant bacteria. Furthermore, we analyzed associations of farm management with AMR. Case-control study: For isolation of indicator Escherichia (E.) coli, rectal swab samples were taken. Cows were sampled depending on treatment history and proximity to one another (cow A: recently treated parenterally; cow B: untreated, next to cow A; cow C: untreated, at considerable distance from all treated cows). Antimicrobial susceptibility was tested by microdilution. Associations of AMR with exposure to cow A, treatments, and management were analyzed using generalized mixed-effects logistic models. Susceptibility data on 571 isolates from 131 dairy farms were obtained. Almost no difference in proportions of resistant E. coli was observed between cows B and C (B: 53.4%; C: 57.2%; P = 0.52). Untreated cows had lower odds of carrying resistant E. coli than treated cows (B: OR 0.44, P<0.001; C: OR 0.54, P = 0.007). Non-pansusceptibility of isolates was associated with antimicrobial treatment (1 treatment: OR 2.11, P = 0.001; ≥2: OR 1.76, P = 0.043). Using manure on forage crops was associated with higher odds of pansusceptibility (OR 2.01, P = 0.004). For daily practice, with regard to the risk of AMR transmission, results of this study do not provide evidence for the need to separate treated cows from others during treatment in tie-stalls.