Presence of an emerging subclone of Francisella tularensis holarctica in Ixodes ricinus ticks from south-western Germany
Presence of an emerging subclone of Francisella tularensis holarctica in Ixodes ricinus ticks from south-western Germany
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DOI：
10.1016/j.ttbdis.2012.09.001
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发表时间：
2013-01-01
影响因子：
3.2
通讯作者：
Splettstoesser, Wolf D.
中科院分区：
文献类型：
--
作者：
Gehringer, Heike;Schacht, Erik;Splettstoesser, Wolf D.
人畜共患病土拉菌病是由细菌病原体土拉弗朗西斯菌引起的。虽然病原体已被发现100年，但对其地方性流行周期的了解仍然很初步。硬蜱是除虻和蚊外的重要媒介和潜在的宿主。土拉热。关于人类土拉菌病发病率的现有数据表明，联邦巴登-符腾堡州的病例有所增加。为了确定蜱是否参与了报告的F。在德国西南部地区，916只蓖麻硬蜱和211只边缘革蜱和D.在两个不同的位置收集网纹蜱。筛选F.通过16 S rRNA基因的实时PCR进行土拉热。在95个I.蓖麻蜱916只，阳性率为8.4%。30-bp缺失PCR证实F.存在土拉热亚种holarctica。FtM 24 VNTR分析表明，它们属于F.北极土拉热菌在211只革蜱属蜱中，随机选择35个DNA进行16 S rRNA基因筛选PCR，其中20个（57%）给出阳性信号。为了进行聚类分析，所有弗朗西斯菌阳性I.对筛选阳性的蓖麻池和6只革蜱进行PCR扩增和测序。在由此产生的邻居加入树，所有弗朗西斯阳性I。蓖麻样品与F. tularensis，而所有革蜱样本与FLE（弗朗西斯菌样内共生体）序列聚类。研究表明，I.蓖麻蜱可作为F.土拉菌病在德国的流行，并支持这一假设，即巴登符腾堡州代表一个新兴的地方性重点土拉菌病。(C)2012年爱思唯尔有限公司。All rights reserved.
The zoonotic disease tularaemia is caused by the bacterial pathogen Francisella tularensis. Although the causative agent is known for 100 years, knowledge of its enzootic cycles is still rudimentary. Apart from tabanids and mosquitoes, hard ticks have been described as important vectors and potential reservoirs for F. tularensis. Available data on the incidence of human tularaemia indicate an increase in cases in the federal state of Baden-Wuerttemberg. To determine whether ticks are involved in the reported increase in F. tularensis infections in humans and wildlife in this south-western part of Germany, 916 Ixodes ricinus and 211 adult Dermacentor marginatus and D. reticulatus ticks were collected in two different locations. Screening for the presence of F. tularensis was performed by real-time PCR of the 16S rRNA gene. Of the 95 pools of I. ricinus ticks (representing 916 individual ticks), 8 tick pools (8.4%) were positive in this PCR. 30-bp deletion PCR confirmed that the F. tularensis subspecies holarctica was present. FtM24 VNTR analysis revealed that they belong to the emerging Franco-Iberian subclone group of F. tularensis holarctica. Of the 211 ticks of the genus Dermacentor, 35 randomly chosen DNAs were subjected to 16S rRNA gene screening PCR; 20 of these (57%) gave positive signals. For cluster analysis, the IpnA gene region of all Francisella-positive I. ricinus pools and 6 Dermacentor ticks with a positive reaction in the screening PCR was amplified and sequenced. In the resulting neighbour-joining tree, all Francisella-positive I. ricinus samples clustered with sequences of F. tularensis, whilst all Dermacentor tick samples clustered with FLE (Francisella-like endosymbiont) sequences. This study shows that I. ricinus ticks may serve as vectors and/or reservoirs of F. tularensis in Germany and supports the hypothesis that the state of Baden-Wuerttemberg represents an emerging endemic focus of tularaemia. (C) 2012 Elsevier GmbH. All rights reserved.