Miranda Jorge, Mattar Salim
Instituto de Investigaciones Biológicas del Trópico, Facultad de Medicina Veterinaria y Zootecnia, Universidad de Córdoba, Córdoba, Colombia.
Instituto de Investigaciones Biológicas del Trópico, Facultad de Medicina Veterinaria y Zootecnia, Universidad de Córdoba, Córdoba, Colombia.
Ticks Tick Borne Dis. 2014 Mar;5(2):208-12. doi: 10.1016/j.ttbdis.2013.10.008. Epub 2013 Dec 27.
The purpose of this study was to provide molecular evidence of Rickettsia spp. in ticks collected from 2 sites of Cordoba. From May to June 2009, 1069 Amblyomma cajennense ticks were removed from 40 capybaras (Hydrochoerus hydrochaeris) in a rural locality of Monteria. Furthermore, 458 Amblyomma sp. larvae and 20 Amblyomma sp. nymphs were collected in a rural locality of Los Cordobas (Cordoba) by drag sampling on vegetation (n=1547). Ticks were grouped into pools and tested for rickettsial infection by real-time PCR targeting the rickettsial gene gltA. Subsequently, PCR targeting for gltA, ompA, ompB, and 16S rRNA, sequencing, and phylogenetic analyses were undertaken. Rickettsial DNA was detected in 10 (4.6%) out of 214 pools of ticks by RT-PCR. Five (33%) of free-living Amblyomma sp. larval pools were positive, as well as 5 (2.6%) pools from A. cajennense. Only the gltA gene was amplified from 5 pools of free-living larvae. The nucleotide sequences were 100% identical to R. bellii by BLAST. Only one pool from A. cajennense was positive for gltA, ompA, ompB, and 16S rRNA. The partial nucleotide sequences of these genes were 100% identical to nucleotide sequences of the same genes of a new proposed species Candidatus Rickettsia sp. strain Colombianensi. This is the first report of R. bellii in ticks in Colombia and the second report of detection of Candidatus Rickettsia sp. strain Colombianensi. These Rickettsia species are still considered of unknown pathogenicity. Further studies are needed to characterize the ecological and potential pathogenic role of these 2 Rickettsia species found in Cordoba.
本研究的目的是为从科尔多瓦两个地点采集的蜱中存在立克次体属提供分子证据。2009年5月至6月，在蒙特里亚的一个农村地区，从40只水豚（Hydrochoerus hydrochaeris）身上采集了1069只卡延花蜱（Amblyomma cajennense）。此外，通过在洛斯科尔多瓦斯（科尔多瓦）一个农村地区的植被上拖网采样（n = 1547），收集了458只安氏硬蜱属幼虫和20只安氏硬蜱属若虫。将蜱分组后，通过针对立克次体基因gltA的实时PCR检测立克次体感染。随后，进行了针对gltA、ompA、ompB和16S rRNA的PCR、测序及系统发育分析。通过RT-PCR在214组蜱中检测到10组（4.6%）存在立克次体DNA。5组（33%）自由生活的安氏硬蜱属幼虫组呈阳性，5组（2.6%）卡延花蜱组也呈阳性。仅从5组自由生活的幼虫中扩增出gltA基因。通过BLAST分析，其核苷酸序列与贝利立克次体（R. bellii）的序列100%相同。卡延花蜱中只有一组gltA、ompA、ompB和16S rRNA呈阳性。这些基因的部分核苷酸序列与新提出的物种柯氏立克次体属（Candidatus Rickettsia sp.）菌株哥伦比亚种（Colombianensi）相同基因的核苷酸序列100%相同。这是贝利立克次体在哥伦比亚蜱中的首次报道，也是柯氏立克次体属菌株哥伦比亚种检测的第二次报道。这些立克次体物种的致病性仍不明确。需要进一步研究来明确在科尔多瓦发现的这两种立克次体物种的生态及潜在致病作用。
