Abstract:

Objective To explore the prevalence of Bartonella in small mammals in some regions of Inner Mongolia, and provide scientific basis for the control and prevention of Bartonella infection in population of small mammals in Inner Mongolia. Methods Night trapping methods were applied to capture small mammals in different regions of Inner Mongolia in 2012 and 2013. Livers and spleens were collected by aseptic technique, and then the tissues were subjected to PCR to test the infection of Bartonella. Afterward, the positive PCR products were sequenced, and the nucleotide sequences were submitted to GenBank accompanying further comparison and analysis. To identify the species of Bartonella, 30 livers and 30 spleens samples were cultivated for Bartonella bacteria, and then extract DNA of suspected strains. Subsequently, sequence the 379 bp fragment of gltA gene and make a phylogenetic analysis. In addition, the prevalence of Bartonella was analyzed based on different species and viscera. Results The small mammals were captured in Erenhot, Xilin Gol, Inner Mongolia in 2012, and positive Bartonella was cultured from 8 species of small mammals corresponding positive rate 56.41%(66/117). The positive rate of liver DNA amplification performed by direct PCR was 57.26% (67/117). There was no marked significance between them (P=0.945). 21 of the 30 liver samples were positive for Bartonella while 13 of the 30 spleens samples were positive. There was no statistic significance between them (P=0.331). 86 small mammals were captured in 2013, including 13 species of rodents, and 33 stains of Bartonella were isolated from these rodents with infection rate 38.37%(33/86). As to the positive infection rate of Bartonella, the highest infection rate was Spermophilus dauricus (75.00%), followed by Allactaga sibirica (71.43%) and Lasiopodomys brandti (64.29%). There were no significant differences in Bartonella prevalence among three species of small mammals (P=0.883). Total of 4 strains of Bartonella were confirmed from small mammals in some regions of Inner Mongolia via DNA sequencing in the rodents: B. jaculi, B. grahamii, B. washoensis, B. vinsonii. Conclusion Bartonella is widespread in small mammals in Inner Mongolia, which increase the risk to human population. Sequencing analysis shows the diversity of genotype of Bartonella. Our study provides a solid foundation for the further research on Bartonella in Inner Mongolia and other regions in northern China.

Key words: Bartonella, Small mammals, Phylogenetic analysis

摘要：

目的 了解我国内蒙古部分地区小型兽类的巴尔通体(Bartonella)感染情况,为该地区人群巴尔通体感染的预防控制提供科学依据。方法 2012、2013年用夹夜法在内蒙古不同地区捕获小型兽类,无菌操作取鼠肝和脾,用聚合酶链反应(PCR)检测巴尔通体,对阳性产物测序,将所测核酸序列提交到GenBank,做相似性比较及序列分析。同时分别用肝和脾各30份样品分离培养巴尔通体,疑似菌株提取DNA,对gltA 基因测序并根据序列进行系统发育分析,确定巴尔通体属种,并分析不同脏器、不同鼠种的阳性率。结果 2012年在内蒙古锡林郭勒盟二连浩特市共捕鼠8种117只,各鼠种均培养出巴尔通体菌,培养阳性率为56.41%(66/117),肝脏DNA直接PCR阳性率为57.26%(67/117),二者差异无统计学意义(P=0.945)。30份肝样品培养阳性21份,30份脾样品培养阳性13份,二者差异亦无统计学意义(P=0.331)。2013年捕获并培养分离小型兽类13种86只,有8种检出巴尔通体,培养阳性率为38.37%(33/86),其中达乌尔黄鼠最高(75.00%),其次为五趾跳鼠(71.43%)和布氏田鼠(64.29%)。经分析达乌尔黄鼠、五趾跳鼠与布氏田鼠的巴尔通体阳性率差异无统计学意义(P=0.883)。序列分析表明内蒙古部分地区小型兽类中共检出4个巴尔通体种群:B. jaculi、B. grahamii、B. washoensis 和B. vinsonii,有明显的宿主特异性。结论 巴尔通体在内蒙古部分地区小型兽类中广泛存在,存在对人群致病的风险,序列分析显示出巴尔通体基因型别的多样性,为内蒙古及我国北方其他地区巴尔通体的研究奠定了基础。

关键词: 巴尔通体, 小型兽类, 遗传进化分析