Feeding on a Bartonella henselae infected host triggers temporary changes in the Ctenocephalides felis microbiome

The effect of Bartonella henselae on the microbiome of its vector, Ctenocephalides felis (the cat flea) is largely unknown, as a majority of C. felis microbiome studies have utilized wild-caught pooled fleas. Therefore, we surveyed the microbiome of laboratory-origin C. felis fed on B. henselae-infected cats to identify changes to microbiome diversity and microbe prevalence compared to unfed fleas, and fleas fed on uninfected cats. To evaluate changes over time, fleas were fed on cats for 24 hours or 9 days. Utilizing Next Generation Sequencing (NGS) on the Illumina platform, we documented an increase in microbial diversity, richness, and evenness in C. felis fed on Bartonella-infected cats for 24 hours, changes that returned to baseline (unfed fleas or fleas fed on uninfected cats) after 9 days on the host. The increased diversity in the C. felis microbiome when fed on B. henselae-infected cats may be related to the mammalian, flea, or endosymbiont response, factors that remain to be explored and potentially exploited for pathogen control. In addition, poor B. henselae acquisition was documented in these laboratory-maintained C. felis. Potential hypotheses to account for this finding include poor acquisition by adult fleas, the influence of flea genetic variation on B. henselae acquisition, and lack of co-feeding with B. henselae-infected C. felis. This study provides an investigation of the C. felis microbiome response to blood feeding and blood-feeding on B. henselae-infected cats; however, future studies are necessary to fully characterize the effect of endosymbionts and C. felis diversity on B. henselae acquisition.

汉塞巴尔通体（Bartonella henselae）对其媒介生物猫栉首蚤（Ctenocephalides felis，即猫跳蚤）微生物组的影响目前尚不明确，因绝大多数针对猫栉首蚤微生物组的研究均采用野生捕获的混合跳蚤样本。为此，本研究针对以汉塞巴尔通体感染的猫咪为食的实验室饲养猫栉首蚤的微生物组开展调查，旨在对比未吸血跳蚤、以未感染猫咪为食的跳蚤的微生物组，明确其微生物组多样性与微生物检出率的变化。为评估菌群随时间推移的变化，本研究设置了吸血24小时与吸血9天两个跳蚤组。本研究利用Illumina平台的下一代测序（Next Generation Sequencing, NGS）技术发现，以汉塞巴尔通体感染的猫咪为食24小时的猫栉首蚤，其微生物多样性、丰富度与均匀度均显著提升；而吸血9天后，该变化恢复至基线水平（即未吸血跳蚤或喂食未感染猫咪的跳蚤组）。以汉塞巴尔通体感染的猫咪为食的猫栉首蚤微生物组多样性提升，可能与宿主哺乳动物、跳蚤自身或内共生体的应答反应相关，这些潜在影响因素仍有待进一步探究，且有望为病原体防控提供新的思路。此外，本研究发现实验室饲养的猫栉首蚤对汉塞巴尔通体的获取率较低。针对该结果的潜在解释假说包括：成虫跳蚤的病原体获取能力较差、跳蚤遗传变异对汉塞巴尔通体获取率的影响，以及未与汉塞巴尔通体感染的猫栉首蚤共同吸血。本研究探讨了猫栉首蚤微生物组对吸血行为以及以汉塞巴尔通体感染的猫咪吸血的应答反应，但未来仍需开展相关研究，以全面阐明内共生体与猫栉首蚤多样性对汉塞巴尔通体获取率的影响。