Laboratório de Biologia Computacional e Sistemas, IOC, FIOCRUZ, Rio de Janeiro, Brazil.
PLoS Negl Trop Dis. 2012;6(5):e1631. doi: 10.1371/journal.pntd.0001631. Epub 2012 May 1.
Chagas disease is a trypanosomiasis whose agent is the protozoan parasite Trypanosoma cruzi, which is transmitted to humans by hematophagous bugs known as triatomines. Even though insecticide treatments allow effective control of these bugs in most Latin American countries where Chagas disease is endemic, the disease still affects a large proportion of the population of South America. The features of the disease in humans have been extensively studied, and the genome of the parasite has been sequenced, but no effective drug is yet available to treat Chagas disease. The digestive tract of the insect vectors in which T. cruzi develops has been much less well investigated than blood from its human hosts and constitutes a dynamic environment with very different conditions. Thus, we investigated the composition of the predominant bacterial species of the microbiota in insect vectors from Rhodnius, Triatoma, Panstrongylus and Dipetalogaster genera.
METHODOLOGY/PRINCIPAL FINDINGS: Microbiota of triatomine guts were investigated using cultivation-independent methods, i.e., phylogenetic analysis of 16s rDNA using denaturing gradient gel electrophoresis (DGGE) and cloned-based sequencing. The Chao index showed that the diversity of bacterial species in triatomine guts is low, comprising fewer than 20 predominant species, and that these species vary between insect species. The analyses showed that Serratia predominates in Rhodnius, Arsenophonus predominates in Triatoma and Panstrongylus, while Candidatus Rohrkolberia predominates in Dipetalogaster.
CONCLUSIONS/SIGNIFICANCE: The microbiota of triatomine guts represents one of the factors that may interfere with T. cruzi transmission and virulence in humans. The knowledge of its composition according to insect species is important for designing measures of biological control for T. cruzi. We found that the predominant species of the bacterial microbiota in triatomines form a group of low complexity whose structure differs according to the vector genus.
恰加斯病是一种由原生动物寄生虫克氏锥虫引起的锥虫病，通过被称为三锥虫的吸血昆虫传播给人类。尽管杀虫剂处理允许在大多数恰加斯病流行的拉丁美洲国家有效控制这些昆虫，但该疾病仍影响着南美洲的很大一部分人口。人类疾病的特征已经得到了广泛的研究，寄生虫的基因组也已经测序，但目前还没有有效的药物来治疗恰加斯病。昆虫传播媒介的消化道比其人类宿主的血液研究得要少得多，并且构成了一个具有非常不同条件的动态环境。因此，我们研究了 Rhodnius、Triatoma、Panstrongylus 和 Dipetalogaster 属昆虫载体中主要细菌物种的微生物群落组成。
方法/主要发现：使用非培养方法，即使用变性梯度凝胶电泳（DGGE）和克隆测序的 16s rDNA 系统发育分析，研究了三锥虫肠道的微生物群。Chao 指数表明，三锥虫肠道细菌物种的多样性较低，包含少于 20 种主要物种，并且这些物种在昆虫物种之间有所不同。分析表明，在 Rhodnius 中，主要是沙雷氏菌，在 Triatoma 和 Panstrongylus 中，主要是阿氏菌，而在 Dipetalogaster 中，主要是 Rohrkolberia 候选菌。
结论/意义：三锥虫肠道的微生物群是可能干扰克氏锥虫在人类中的传播和毒力的因素之一。根据昆虫种类了解其组成对于设计克氏锥虫的生物控制措施很重要。我们发现，三锥虫肠道细菌微生物群的主要物种形成了一个低复杂度的群体，其结构根据载体属而有所不同。
