摘要
出身背景
不同畜牧生产系统中的畜牧业实践和牲畜与野生动物相互作用的增加被认为是干旱和半干旱地区抗微生物耐药性（AMR）的主要驱动因素。尽管在过去十年中，骆驼的数量增加了十倍，再加上骆驼产品的广泛使用，但缺乏关于这些生产系统中产生β-内酰胺酶的大肠杆菌（E.coli）的全面信息。
目标
我们的研究试图建立AMR谱，并从肯尼亚北部骆驼群的粪便样本中分离出新出现的产β-内酰胺酶的大肠杆菌，并对其进行鉴定。
方法
采用纸片扩散法建立了大肠杆菌分离株的耐药性谱，并对β-内酰胺酶（bla）基因进行了PCR产物测序，进行了系统发育分组和遗传多样性评估。
后果
我们发现，在回收的大肠杆菌分离株（n=123）中，对头孢克洛的耐药性最高，为28.5%，其次是头孢噻肟，为16.3%，氨苄青霉素，为9.7%。此外，在3.3%的总样本中检测到携带blaCTX-M-15或blaCTX-M-27基因的产超广谱β-内酰胺酶（ESBL）的大肠杆菌，并且与系统发育组B1、B2和D相关。检测到非ESBL blaTEM基因的多个变体，其中大多数是blaTEM-1和blaTEM-116基因。
结论
这项研究的结果揭示了在具有多药耐药性表型的大肠杆菌分离株中，ESBL和非ESBL编码基因变异的发生率增加。这项研究强调了扩大“一个健康”方法的必要性，以了解AMR的传播动态、AMR发展的驱动因素，以及ASAL内骆驼生产系统中抗菌药物管理的适当实践。
Abstract
Background
Animal husbandry practices in different livestock production systems and increased livestock–wildlife interactions are thought to be primary drivers of antimicrobial resistance (AMR) in Arid and Semi-Arid Lands (ASALs). Despite a tenfold increase in the camel population within the last decade, paired with widespread use of camel products, there is a lack of comprehensive information concerning beta-lactamase-producing Escherichia coli (E. coli) within these production systems.

Objectives
Our study sought to establish an AMR profile and to identify and characterise emerging beta-lactamase-producing E. coli isolated from faecal samples obtained from camel herds in Northern Kenya.

Methods
The antimicrobial susceptibility profiles of E. coli isolates were established using the disk diffusion method, with beta-lactamase (bla) gene PCR product sequencing performed for phylogenetic grouping and genetic diversity assessments.

Results
Here we show, among the recovered E. coli isolates (n = 123), the highest level of resistance was observed for cefaclor at 28.5% of isolates, followed by cefotaxime at 16.3% and ampicillin at 9.7%. Moreover, extended-spectrum beta-lactamase (ESBL)-producing E. coli harbouring the blaCTX-M-15 or blaCTX-M-27 genes were detected in 3.3% of total samples, and are associated with phylogenetic groups B1, B2 and D. Multiple variants of non-ESBL blaTEM genes were detected, the majority of which were the blaTEM-1 and blaTEM-116 genes.

Conclusions
Findings from this study shed light on the increased occurrence of ESBL- and non-ESBL-encoding gene variants in E. coli isolates with demonstrated multidrug resistant phenotypes. This study highlights the need for an expanded One Health approach to understanding AMR transmission dynamics, drivers of AMR development, and appropriate practices for antimicrobial stewardship in camel production systems within ASALs.

https://onlinelibrary.wiley.com/doi/full/10.1002/vms3.1090