背景：
抗菌素耐药性（AMR）是一个严重的健康问题，全身抗菌治疗推动AMR在宿主谱中的发展。

目的：
本研究比较了在多个时间点对接受常规抗菌治疗的狗的AMR粪便大肠杆菌的纵向运输。

方法：
来自狗（n = 127）的粪便样品（n = 457）在治疗前，治疗后立即和用五种抗微生物剂中的一种治疗后1个月和3个月进行检查。在不同时间点对每个处理组使用盘扩散测试分离物对一系列抗微生物剂的敏感性;使用PCR测定法研究相应抗性基因的存在/不存在。使用多级建模研究治疗组/时间点和其他风险因素对耐药性[MDR，氟喹诺酮耐药性，第三代头孢菌素抗性（3GCR）和ESBL和AmpC产生]的影响。具有至少一种来自选择性/非选择性琼脂的AMR大肠杆菌的样品被归类为阳性。还在分离物水平评估抗性，确定来自非选择性培养物的AMR的丰度。

结果：
用β-内酰胺类或氟喹诺酮类药物治疗与治疗后立即检测3GCR，产AmpC，MDR和/或氟喹诺酮耐药的大肠杆菌，而不是产ESBL的大肠杆菌显着相关。然而，治疗后1个月，只有阿莫西林/克拉维酸与3GCR的检测显着相关;与预处理样品相比，任何抗菌剂在处理后3个月没有显着差异。

结论：
我们的研究结果表明，β-内酰胺和氟喹诺酮抗生素的使用与兽医访视犬常规治疗后重要的表型和基因型AMR粪便大肠杆菌的检测增加有关。这对于兽医和公共卫生在抗菌处方和生物安全协议以及狗废物处理方面具有重要意义。

BACKGROUND:
Antimicrobial resistance (AMR) is a critical health problem, with systemic antimicrobial therapy driving development of AMR across the host spectrum.

OBJECTIVES:
This study compares longitudinal carriage, at multiple timepoints, of AMR faecal Escherichia coli in dogs undergoing routine antimicrobial treatment.

METHODS:
Faecal samples (n = 457) from dogs (n = 127) were examined pretreatment, immediately after treatment and 1 month and 3 months post-treatment with one of five antimicrobials. Isolates were tested for susceptibility to a range of antimicrobials using disc diffusion for each treatment group at different timepoints; the presence/absence of corresponding resistance genes was investigated using PCR assays. The impact of treatment group/timepoint and other risk factors on the presence of resistance [MDR, fluoroquinolone resistance, third-generation cephalosporin resistance (3GCR) and ESBL and AmpC production] was investigated using multilevel modelling. Samples with at least one AMR E. coli from selective/non-selective agar were classed as positive. Resistance was also assessed at the isolate level, determining the abundance of AMR from non-selective culture.

RESULTS:
Treatment with β-lactams or fluoroquinolones was significantly associated with the detection of 3GCR, AmpC-producing, MDR and/or fluoroquinolone-resistant E. coli, but not ESBL-producing E. coli, immediately after treatment. However, 1 month post-treatment, only amoxicillin/clavulanate was significantly associated with the detection of 3GCR; there was no significant difference at 3 months post-treatment for any antimicrobial compared with pretreatment samples.

CONCLUSIONS:
Our findings demonstrated that β-lactam and fluoroquinolone antibiotic usage is associated with increased detection of important phenotypic and genotypic AMR faecal E. coli following routine therapy in vet-visiting dogs. This has important implications for veterinary and public health in terms of antimicrobial prescribing and biosecurity protocols, and dog waste disposal.

https://www.ncbi.nlm.nih.gov/pubmed/30215725