摘要
出身背景
抗生素耐药性基因（ARGs）的传播一直是全球关注的最大环境威胁之一。动物的肠道微生物组被发现是ARGs的一个巨大库，这也是环境抗生素谱的一个指标。保守的微生物群使蜜蜂成为一个易于处理和封闭的生态系统，用于研究ARG在肠道细菌中的维持和转移。尽管已经发现蜜蜂肠道细菌携带多种ARG，但环境变量的影响及其分布机制仍不清楚。
后果
我们对在中国14个地理位置驯化的两种亲缘关系密切的蜜蜂——中华蜜蜂和意大利蜜蜂的肠道抗性进行了表征。ARGs的组成更多地与宿主物种有关，而不是与地理分布有关，并且意大利香茅在肠道中的ARGs含量更高。抗性分布具有中等的地理模式，并且发现几个核心ARG组在角龙样品中普遍存在。这些共享基因主要由蜜蜂特有的肠道成员Gilliamella和Snodgrassella携带。在蜜蜂的肠道中经常检测到可转移的ARGs，而在A.mellifera样本中的含量要高得多。含有链霉素抗性基因簇的蜜蜂肠道共生体的基因组基因座与广泛宿主范围的IncQ质粒（一种在环境中熟练的DNA递送系统）的基因座几乎相同。通过体外结合实验，我们证实了可移动质粒可以通过结合在蜜蜂肠道共生体之间转移。此外，在来自多个地区的不同共生体的整合区域中发现了具有片段化基因的“卫星质粒”。
结论
我们的研究表明，不同蜜蜂宿主的肠道微生物群的抗生素耐药性结构各不相同，这突出了蜜蜂微生物组作为抗生素耐药性的潜在生物指示剂和传播者的作用。驯化历史的差异对蜜蜂肠道抵抗体的结构有很大影响。值得注意的是，质粒介导的抗生素耐药性的演变可能会提高其持久性和传播的概率。
Abstract
Background
The spread of antibiotic resistance genes (ARGs) has been of global concern as one of the greatest environmental threats. The gut microbiome of animals has been found to be a large reservoir of ARGs, which is also an indicator of the environmental antibiotic spectrum. The conserved microbiota makes the honeybee a tractable and confined ecosystem for studying the maintenance and transfer of ARGs across gut bacteria. Although it has been found that honeybee gut bacteria harbor diverse sets of ARGs, the influences of environmental variables and the mechanism driving their distribution remain unclear.

Results
We characterized the gut resistome of two closely related honeybee species, Apis cerana and Apis mellifera, domesticated in 14 geographic locations across China. The composition of the ARGs was more associated with host species rather than with geographical distribution, and A. mellifera had a higher content of ARGs in the gut. There was a moderate geographic pattern of resistome distribution, and several core ARG groups were found to be prevalent among A. cerana samples. These shared genes were mainly carried by the honeybee-specific gut members Gilliamella and Snodgrassella. Transferrable ARGs were frequently detected in honeybee guts, and the load was much higher in A. mellifera samples. Genomic loci of the bee gut symbionts containing a streptomycin resistance gene cluster were nearly identical to those of the broad-host-range IncQ plasmid, a proficient DNA delivery system in the environment. By in vitro conjugation experiments, we confirmed that the mobilizable plasmids could be transferred between honeybee gut symbionts by conjugation. Moreover, “satellite plasmids” with fragmented genes were identified in the integrated regions of different symbionts from multiple areas.

Conclusions
Our study illustrates that the gut microbiota of different honeybee hosts varied in their antibiotic resistance structure, highlighting the role of the bee microbiome as a potential bioindicator and disseminator of antibiotic resistance. The difference in domestication history is highly influential in the structuring of the bee gut resistome. Notably, the evolution of plasmid-mediated antibiotic resistance is likely to promote the probability of its persistence and dissemination.

https://link.springer.com/article/10.1186/s40168-022-01268-1