Antibiotic consumption is a major driver of antibiotic resistance in calves raised on Italian cow-calf beef farms

• Published in: Research in veterinary science Vol. 145; pp. 71 - 81
• Main Authors: Ferroni, L., Albini, E., Lovito, C., Blasi, F., Maresca, C., Massacci, F.R., Orsini, S., Tofani, S., Pezzotti, G., Diaz Vicuna, E., Forte, C., Magistrali, C.F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-07-2022; Elsevier Limited
• Subjects: Agriculture; Animal welfare; Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Antibiotic consumption; Antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Beef; Beef cattle; beta-Lactamases; Calves; Cattle; Cattle Diseases - drug therapy; Cattle Diseases - epidemiology; Confidence intervals; Consumption; Data collection; Drug resistance; Drug Resistance, Microbial; E coli; Escherichia coli; Escherichia coli Infections - veterinary; Farmers; Farms; Female; Fluoroquinolones; Livestock; Public health; Regression models; Resistance factors; Risk analysis; Risk factors; Rural areas; Statistical analysis; Sulfonamides; Sustainability; Tetracyclines; Veterinary medicine; β-Lactam antibiotics; Italy; Europe; Germany; Livestock; Cattle; Antibiotic consumption; Escherichia coli; Risk factors; Antibiotic resistance
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2022.01.010

Although its importance, little information is available on antibiotic-resistance in cow-calf beef farms. This study aimed to determine prevalence and risk factors for antibiotic-resistant organisms in this livestock system. Fifty-four farms from Central Italy were included to assess the presence of antibiotic-resistant indicator Escherichia coli and of ESBL and/or AmpC-producing E. coli (ESBL/AmpC-EC) in calves. Antimicrobial usage (AMU) was recorded, and farm-related variables were collected through questionnaires. Potential risk factors were tested using a mixed-effects logistic regression model. The presence of resistant-E. coli was recorded in 75.9% of farms (95% confidence interval [CI]: 62.4–86.5) with resistance to tetracyclines, sulfonamides, penicillins, and fluoroquinolones as the most frequent. The prevalence of farms positive for ESBL/AmpC-EC was 35.2% (95% CI: 22.7–49.4). AMU on the farms originating a resistant-E. coli was higher than that on the farms originating a susceptible-E. coli. The same difference was found for the consumption of beta-lactams (beta-DCD/year) and AMU via the parenteral route, which resulted also associated with the presence of ESBL/AmpC-EC. Farms with higher beta-DCD/year had an increased risk of being positive for resistant-E. coli, whereas farms with higher overall AMU had an increased risk for ESBL/AmpC-EC presence. Among farm-related factors, only farm size was associated with the presence of ESBL/AmpC-EC (odds ratio: 5.8, 95% CI: 1.3–26.3).
Our findings highlight a reduction of the risk of ESBL/AmpC-EC in small cow-calf farms, and a strong association between AMU and antibiotic-resistance. Antibiotic stewardship programs are needed to improve the health status of cow-calf farms and ensure their long-term sustainability.
•Overall, 79% of cow-calf beef farms had at least one AR indicator E. coli in calves.•Multi-resistant isolates were found in 50% of farms.•Farms with high beta-lactam consumption were at increased risk of AR E. coli.•Farms with high antibiotic consumption were at risk of ESBL/AmpC-producing E. coli.•A large farm size was associated with ESBL-/AmpC-producing E. coli.