BACKGROUND Honey bees, Apis mellifera, face many parasites and pathogens and consequently rely on a diverse set of individual and group-level defenses to prevent disease. One route by which honey bees and other insects might combat disease is through the shielding effects of their microbial symbionts. Bees carry a diverse assemblage of bacteria, very few of which appear to be pathogenic. Here we explore the inhibitory effects of these resident bacteria against the primary bacterial pathogen of honey bees, Paenibacillus larvae. RESULTS Here we isolate, culture, and describe by 16S rRNA and protein-coding gene sequences 61 bacterial isolates from honey bee larvae, reflecting a total of 43 distinct bacterial taxa. We culture these bacteria alongside the primary larval pathogen of honey bees, Paenibacillus larvae, and show that many of these isolates severely inhibit the growth of this pathogen. Accordingly, symbiotic bacteria including those described here are plausible natural antagonists toward this widespread pathogen. CONCLUSION The results suggest a tradeoff in social insect colonies between the maintenance of potentially beneficial bacterial symbionts and deterrence at the individual and colony level of pathogenic species. They also provide a novel mechanism for recently described social components behind disease resistance in insect colonies, and point toward a potential control strategy for an important bee disease.

中文翻译：

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蜜蜂细菌共生体之间的拮抗相互作用及其对疾病的影响。

背景技术蜜蜂（Apis mellifera）面对许多寄生虫和病原体，因此依赖于个人和团体水平的各种防御来预防疾病。蜜蜂和其他昆虫可能与疾病作斗争的一种途径是通过微生物共生体的屏蔽作用。蜜蜂携带各种各样的细菌，其中很少有致病性的。在这里，我们探讨了这些常驻细菌对蜜蜂的主要细菌病原体潘氏杆菌幼虫的抑制作用。结果在这里，我们从16S rRNA和蛋白质编码基因序列中分离，培养和描述了61种来自蜜蜂幼虫的细菌分离株，反映了总共43种不同的细菌类群。我们将这些细菌与蜜蜂的主要幼虫病原体Paenibacillus幼虫一起培养，并表明许多分离株严重抑制了这种病原体的生长。因此，包括在此描述的共生细菌是针对这种广泛病原体的合理的天然拮抗剂。结论该结果表明，在维持潜在有益细菌共生体与在病原体的个体和菌落水平上的威慑之间，社会昆虫菌落之间需要进行权衡。它们还为昆虫群体中抗病性背后的最近描述的社会因素提供了一种新颖的机制，并指出了重要蜜蜂疾病的潜在控制策略。结论该结果表明，在维持潜在有益细菌共生体与在病原体的个体和菌落水平上的威慑之间，社会昆虫菌落之间需要进行权衡。它们还为昆虫群体中抗病性背后的最近描述的社会因素提供了一种新颖的机制，并指出了重要蜜蜂疾病的潜在控制策略。结论该结果表明，在维持潜在有益细菌共生体与在病原体的个体和菌落水平上的威慑之间，社会昆虫菌落之间需要进行权衡。它们还为昆虫群体中抗病性背后的最近描述的社会因素提供了一种新颖的机制，并指出了重要蜜蜂疾病的潜在控制策略。