Muletz-Wolz Carly R, Almario Jose G, Barnett Samuel E, DiRenzo Graziella V, Martel An, Pasmans Frank, Zamudio Kelly R, Toledo Luís Felipe, Lips Karen R
Department of Biology, University of Maryland, College ParkMD, United States.
Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, WashingtonDC, United States.
Front Microbiol. 2017 Aug 21;8:1551. doi: 10.3389/fmicb.2017.01551. eCollection 2017.
Symbiotic bacteria may dampen the impacts of infectious diseases on hosts by inhibiting pathogen growth. However, our understanding of the generality of pathogen inhibition by different bacterial taxa across pathogen genotypes and environmental conditions is limited. Bacterial inhibitory properties are of particular interest for the amphibian-killing fungal pathogens ( and ), for which probiotic applications as conservation strategies have been proposed. We quantified the inhibition strength of five putatively -inhibitory bacteria isolated from woodland salamander skin against six genotypes at two temperatures (12 and 18°C). We selected six genotypes from across the phylogeny: -Brazil and four genotypes of the Global Panzootic Lineage (GPL1: JEL647, JEL404; GPL2: SRS810, JEL423). We performed 96-well plate challenge assays in a full factorial design. We detected a genotype by temperature interaction on bacterial inhibition score for all bacteria, indicating that bacteria vary in ability to inhibit depending on pathogen genotype and temperature. moderately inhibited at both temperatures (μ = 46-53%), but not any genotypes. sp. inhibited three genotypes at both temperatures (μ = 5-71%). sp. strain 1 inhibited all genotypes at 12°C and four genotypes at 18°C (μ = 5-100%). sp. strain 2 and sp. moderately to strongly inhibited all six genotypes at both temperatures (μ = 57-100%). All bacteria consistently inhibited . Using cluster analysis of inhibition scores, we found that more closely related genotypes grouped together, suggesting that bacterial inhibition strength may be predictable based on relatedness. We conclude that bacterial inhibition capabilities change among bacterial strains, genotypes and temperatures. A comprehensive understanding of bacterial inhibitory function, across pathogen genotypes and temperatures, is needed to better predict the role of bacterial symbionts in amphibian disease ecology. For targeted conservation applications, we recommend using bacterial strains identified as strongly inhibitory as they are most likely to produce broad-spectrum antimicrobial agents at a range of temperatures.
共生细菌可能通过抑制病原体生长来减轻传染病对宿主的影响。然而，我们对于不同细菌分类群在不同病原体基因型和环境条件下抑制病原体的普遍性的理解是有限的。细菌的抑制特性对于导致两栖动物死亡的真菌病原体（ 和 ）尤为重要，针对这些病原体，有人提出了将益生菌应用作为保护策略。我们量化了从林地蝾螈皮肤中分离出的五种假定具有抑制作用的细菌在两种温度（12°C和18°C）下对六种 基因型的抑制强度。我们从 系统发育中选择了六种基因型： -巴西以及全球泛动物疫情谱系的四种基因型（GPL1：JEL647、JEL404；GPL2：SRS810、JEL423）。我们采用全因子设计进行了96孔板挑战试验。我们检测到所有细菌的细菌抑制得分存在基因型与温度的相互作用，这表明细菌抑制 的能力因病原体基因型和温度而异。 在两种温度下都对 有适度抑制作用（μ = 46 - 53%），但对任何 基因型均无抑制作用。 菌在两种温度下抑制了三种 基因型（μ = 5 - 71%）。 菌菌株1在12°C时抑制了所有 基因型，在18°C时抑制了四种 基因型（μ = 5 - 100%）。 菌菌株2和 菌在两种温度下对所有六种 基因型都有中度至强烈的抑制作用（μ = 57 - 100%）。所有细菌都持续抑制 。通过对抑制得分进行聚类分析，我们发现亲缘关系更近的 基因型聚集在一起，这表明细菌抑制强度可能基于 亲缘关系而具有可预测性。我们得出结论，细菌的抑制能力在细菌菌株、 基因型和温度之间会发生变化。为了更好地预测细菌共生体在两栖动物疾病生态学中的作用，需要全面了解在不同病原体基因型和温度下细菌的抑制功能。对于有针对性的保护应用，我们建议使用被鉴定为具有强抑制作用的细菌菌株，因为它们最有可能在一系列温度下产生广谱抗菌剂。
