Data from: Novel evidence suggests that a "Rickettsia felis-like" organism is an endosymbiont of the desert flea, Xenopsylla ramesis

Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pathogenicity. In the present study, fleas collected from wild rodents from the Negev desert in Southern Israel were tested for Rickettsia-DNA by targeting the 16S rRNA (rrs) gene. Thirty eight Xenopsylla ramesis, 91 Synosternus cleopatrae and 15 Leptosylla algira flea-pools (a total of 568 fleas) were screened. Rickettsia-DNA was detected in 100% of the X. ramesis and in one S. cleopatrae flea-pools. None of L. algira flea pools was found positive. All positive flea-pools were further characterized by sequencing of five additional genetic loci (gltA, ompB, ompA, htrA and fusA). The molecular identification of the positive samples showed all sequences to be closely related to the "Rickettsia felis-like" organisms (99-100% similarities in the six loci). In order to further investigate the association between “R. felis-like” and X. ramesis fleas, ten additional single X. ramesis adult fleas collected from the wild and five laboratory maintained X. ramesis imago, five larvae pools (2-18 larvae per pool) and two egg-pools (18 eggs per pool), were tested for the presence of "R. felis-like"-DNA. All samples were found positive by a specific ompA PCR assay, confirming the close association of this Rickettsia species with X. ramesis in all its life stages. These results suggest a symbiotic association between "Rickettsia felis-like" and X. ramesis fleas.

蚤类是公认的多种致病菌的传播媒介与储存宿主，这类细菌具有广泛的致病性。本研究针对以色列南部内盖夫沙漠野生啮齿动物体表采集的蚤类，以16S rRNA（rrs）基因为靶标，检测其立克次体（Rickettsia）DNA。本研究共筛查了38组长爪客蚤（Xenopsylla ramesis）、91组克氏真客蚤（Synosternus cleopatrae）以及15组细蚤（Leptosylla algira）混合蚤样本（总计568只蚤）。检测结果显示，长爪客蚤混合样本的立克次体DNA检出率为100%，另有1组克氏真客蚤混合样本呈阳性；细蚤混合样本均未检出立克次体DNA。所有阳性混合蚤样本进一步通过5个额外遗传位点（gltA、ompB、ompA、htrA及fusA）的测序进行分型鉴定。阳性样本的分子鉴定结果显示，所有序列均与类猫立克次体（Rickettsia felis-like）类群高度同源，在6个位点上的相似度达99%~100%。为进一步探究类猫立克次体与长爪客蚤的关联，本研究额外检测了10只野生采集的长爪客蚤成虫、5只实验室饲养的长爪客蚤成虫、5组长爪客蚤幼虫混合样本（每组含2~18只幼虫）以及2组卵混合样本（每组含18枚卵），以检测类猫立克次体DNA的存在。经特异性ompA聚合酶链式反应（PCR）检测，所有样本均呈阳性，证实该立克次体物种与长爪客蚤在其整个生活史阶段均存在紧密关联。上述结果表明，类猫立克次体与长爪客蚤之间存在共生关联。