Antibiotic resistance is recognised as one of the biggest global threats to human and animal health. Understanding the influence of antibiotics on the canine microbiome is important to know the potential mid-to-long term effects on dysbiosis and mitigate side-effects such as antibiotic-associated diarrhoea. In this study, metronidazole was prescribed to 22 dogs for suspected giardiasis after exhibiting gastrointestinal symptoms such as diarrhoea and/or vomiting. Faecal samples were collected before, during seven days of treatment, and six months post-cessation. Faecal microbiota was assessed with 16S rRNA sequencing. Shannon diversity was reduced for up to three days after the treatment ended, and an altered community persisted for four to six weeks. All dogs recovered to a similar microbiome composition as pre-treatment. Immediately after receiving metronidazole, an increase in the relative abundance of the genera Lactobacillus, Bifidobacterium, and Enterococcus was observed. This may be due to antibiotic resistance commonly exhibited by these organisms. One-to-two weeks post-cessation, several other genera that were sensitive to the antibiotic recovered in abundances, with taxa belonging to the Erysipelotrichaceae family particularly driving composition change. Many of the bacteria initially reduced were associated with carbohydrate fermentation. This suggests scope exists to explore interventions to augment gastrointestinal health and support the re-establishment of the microbiome.

抗生素耐药性被认为是全球人类和动物健康面临的最大威胁之一。了解抗生素对犬类微生物组的影响对于了解抗生素对生态失调的潜在中长期影响并减轻抗生素相关腹泻等副作用非常重要。在这项研究中，22 只狗因疑似贾第鞭毛虫病而出现腹泻和/或呕吐等胃肠道症状，因此给它们开了甲硝唑。在治疗前、治疗7天期间以及停止治疗后6个月收集粪便样本。通过 16S rRNA 测序评估粪便微生物群。治疗结束后，香农多样性最多会降低三天，而改变的群落会持续四到六周。所有狗都恢复到与治疗前相似的微生物组组成。服用甲硝唑后，立即观察到乳杆菌属、双歧杆菌属和肠球菌属的相对丰度增加。这可能是由于这些生物体通常表现出抗生素耐药性。停药后一到两周，其他几个对抗生素敏感的属大量恢复，其中属于丹毒科的类群尤其推动了成分变化。许多最初减少的细菌与碳水化合物发酵有关。这表明探索增强胃肠道健康和支持微生物群重建的干预措施尚有空间。