Flancman Rebecca, Doster Enrique, Gomez Diego E, Ricker Nicole, Morley Paul S, Weese J Scott
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Veterinary Education, Research, and Outreach (VERO) Program, Texas A&M University and West Texas A&M University, Canyon, Texas, USA.
J Vet Intern Med. 2025 Sep-Oct;39(5):e70234. doi: 10.1111/jvim.70234.
Neonatal diarrhea accounts for 20%-25% of morbidity among calves, and antimicrobial drugs (AMDs) are often administered for treatment. Systematic approaches that mitigate antimicrobial use (AMU) can be effective in decreasing antimicrobial resistance (AMR).
HYPOTHESIS/OBJECTIVES: To determine the effects of an algorithmic farm-based intervention that reduced AMU for diarrhea on the community structure of antimicrobial resistance genes (ARGs) identified in the feces of healthy dairy calves.
Thirty-one fecal dairy calf samples collected at two timepoints and farms (N = 7-8 per sampling point) were used. Samples were obtained before AMU reductions and 12 months afterward.
Target-enriched shotgun sequencing was performed to characterize all ARGs in samples. Bioinformatics processing and statistical analysis were performed using the AMR++ pipeline, MEGARes AMR database, and R.
Pre-intervention comparisons showed increased relative abundances (RA) consistent with the AMU on each farm. Intra-farm results showed that on Farm 1, there were significant increases in the RA of ARGs for tetracyclines (22.1%-27.4%, q = 0.02) and fluoroquinolones (0%-0.1%, q < 0.0001) in the Post period. On Farm 2, significant decreases were seen over time in the RA of ARGs for sulfonamides (9.6%-5.1%, q = 0.006) and fluoroquinolones (0.77%-0.12%, q = 0.004).
Despite similar reductions in AMU on both farms, implementing an antimicrobial stewardship algorithm was associated with differing effects on and changes to the fecal resistome.
新生犊牛腹泻占犊牛发病率的20%-25%，抗菌药物（AMDs）常被用于治疗。减轻抗菌药物使用（AMU）的系统方法可有效降低抗菌药物耐药性（AMR）。
假设/目标：确定基于农场的算法干预措施对腹泻减少AMU的效果，该措施针对健康奶牛犊粪便中鉴定出的抗菌药物耐药基因（ARGs）的群落结构。
使用在两个时间点和农场收集的31份奶牛犊粪便样本（每个采样点N = 7-8）。样本在AMU减少前和之后12个月采集。
进行靶向富集鸟枪法测序以表征样本中的所有ARGs。使用AMR++管道、MEGARes AMR数据库和R进行生物信息学处理和统计分析。
干预前比较显示，每个农场的相对丰度（RA）增加与AMU一致。农场内结果显示，在农场1，后期四环素类ARGs的RA显著增加（22.1%-27.4%，q = 0.02），氟喹诺酮类ARGs的RA显著增加（0%-0.1%，q < 0.0001）。在农场2，随着时间推移，磺胺类ARGs的RA显著降低（9.6%-5.1%，q = 0.006），氟喹诺酮类ARGs的RA显著降低（0.77%-0.12%，q = 0.004）。
尽管两个农场的AMU减少情况相似，但实施抗菌药物管理算法对粪便耐药组的影响和变化不同。
