Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Tochigi, Japan.
Unit of Vector Ecology, Institut Pasteur de Tunis, Tunis, Tunisia.
PLoS Negl Trop Dis. 2024 Sep 5;18(9):e0012458. doi: 10.1371/journal.pntd.0012458. eCollection 2024 Sep.
Phlebotomine sand flies are vectors of the protozoan parasite Leishmania spp. Although the intestinal microbiota is involved in a wide range of biological and physiological processes and has the potential to alter vector competence, little is known about the impact of host species and environment on the gut microbiome. To address this issue, a comparative analysis of the microbiota of sand fly vector populations of Leishmania major and L. tropica in a mixed focus of cutaneous leishmaniasis in Tunisia was performed. Bacterial 16S rRNA gene amplification and Illumina MiSeq sequencing were used to characterize and compare the overall bacterial and fungal composition of field-collected sand flies: Phlebotomus papatasi, Ph. perniciosus, Ph. riouxi, and Ph. sergenti. Thirty-eight bacterial genera belonging to five phyla were identified in 117 female specimens. The similarities and differences between the microbiome data from different samples collected from three collections were determined using principal coordinate analysis (PCoA). Substantial variations in the bacterial composition were found between geographically distinct populations of the same sand fly species, but not between different species at the same location, suggesting that the microbiota content was structured according to environmental factors rather than host species. These findings suggest that host phylogeny may play a minor role in determining the insect gut microbiota, and its potential to affect the transmission of the Leishmania parasite appear to be very low. These results highlight the need for further studies to decode sand fly Leishmania-microbiota interactions, as even the same bacterial species, such as Enterococcus faecalis, can exert completely opposite effects when confronted with different pathogens within various host insects and vice versa.
白蛉是原生动物寄生虫利什曼原虫的载体。尽管肠道微生物群参与了广泛的生物学和生理学过程，并有可能改变媒介的感染力，但人们对宿主物种和环境对肠道微生物群的影响知之甚少。为了解决这个问题，我们对突尼斯皮肤利什曼病混合流行地区的利什曼原虫主要和 L. tropica 沙蝇媒介种群的微生物群进行了比较分析。使用细菌 16S rRNA 基因扩增和 Illumina MiSeq 测序来描述和比较现场采集的沙蝇（Phlebotomus papatasi、Ph. perniciosus、Ph. riouxi 和 Ph. sergenti）的总体细菌和真菌组成。在 117 只雌性标本中鉴定出属于五个门的 38 个细菌属。使用主坐标分析（PCoA）确定了来自三个采集地点的不同样本的微生物组数据之间的相似性和差异。尽管同一沙蝇物种的不同地理种群之间的细菌组成存在很大差异，但同一地点的不同物种之间没有差异，这表明微生物群的含量是根据环境因素而不是宿主物种来构建的。这些发现表明，宿主系统发育可能在决定昆虫肠道微生物群方面发挥次要作用，并且其影响利什曼原虫寄生虫传播的潜力似乎非常低。这些结果强调需要进一步研究来解码沙蝇与利什曼原虫的相互作用，因为即使是相同的细菌物种，如粪肠球菌，在不同的宿主昆虫中遇到不同的病原体时也可能产生完全相反的效果，反之亦然。
