Detection of a Potential New Bartonella Species "Candidatus Bartonella rondoniensis" in Human Biting Kissing Bugs (Reduviidae; Triatominae)

Abstract

Background: Among the Reduviidae family, triatomines are giant blood-sucking bugs. They are well known in Central and South America where they transmit Trypanosoma cruzi to mammals, including humans, through their feces. This parasitic protozoan is the causative agent of Chagas disease, a major public health issue in endemic areas. Because of the medical and economic impact of Chagas disease, the presence of other arthropod-borne pathogens in triatomines was rarely investigated.

Methodology/principal findings: In this study, seven triatomines species involved in the transmission of T. cruzi were molecularly screened for the presence of known pathogens generally associated with arthropods, such as Rickettsia, Bartonella, Anaplasmataceae, Borrelia species and Coxiella burnetii. Of all included triatomine species, only Eratyrus mucronatus specimens tested positive for Bartonella species for 56% of tested samples. A new genotype of Bartonella spp. was detected in 13/23 Eratyrus mucronatus specimens, an important vector of T. cruzi to humans. This bacterium was further characterized by sequencing fragments of the ftsZ, gltA and rpoB genes. Depending on the targeted gene, this agent shares 84% to 91% of identity with B. bacilliformis, the agent of Carrion's disease, a deadly sandfly-borne infectious disease endemic in South America. It is also closely related to animal pathogens such as B. bovis and B. chomelii.

Conclusions: As E. mucronatus is an invasive species that occasionally feeds on humans, the presence of potentially pathogenic Bartonella-infected bugs could present another risk for human health, along with the T. cruzi issue.

Fig 1. Distribution of sampling areas in French Guiana.

Exact sampling sites are indicated by a triangle.

Fig 2. Pictures of alive and dead Eratyrus mucronatus in its environment and dried on paper.

Fig 3. A consensus phylogenetic tree showing the relationships of the studied species of Bartonella species based on a portion of rpoB gene sequence comparison.

GenBank accession numbers (or the only genome accession number) are indicated when the sequences initially originated from Genbank. The sequences were aligned using ClustalW, and phylogenetic inferences were obtained using Bayesian phylogenetic analysis with TOPALi 2.5 software (Biomathematics and Statistics Scotland, Edinburgh, UK) within the integrated Maximum Likelihood application using the TrN + I + Г model. Numbers at the nodes are percentages of bootstrap values obtained by repeating the analysis 100 times to generate a majority consensus tree. Bootstrap values below 80 were deleted from the final tree. The final set includes 756 base pairs. The new Bartonella sequence described in the present study is written in red.

Fig 4. A consensus phylogenetic tree showing the relationships of the Bartonella species studied based on a portion of ftsZ gene sequence comparison.

GenBank accession numbers (or the only genome accession number) are indicated when the sequences originated from Genbank at the beginning. The sequences were aligned using ClustalW, and phylogenetic inferences were obtained using Bayesian phylogenetic analysis with TOPALi 2.5 software (Biomathematics and Statistics Scotland, Edinburgh, UK) within the integrated Maximum Likelihood application using the ML SYM+I+Г model. Numbers at the nodes are percentages of bootstrap values obtained by repeating the analysis 100 times to generate a majority consensus tree. Bootstrap values below 80 were deleted from the final tree. The final set includes 292 base pairs. The new Bartonella sequence described in this study is written in red.

Fig 5. A consensus phylogenetic tree showing the relationships of the Bartonella species studied based on a portion of gltA gene sequence comparison.

GenBank accession numbers (or the only genome accession number) are indicated when the sequences originated from Genbank at the beginning. The sequences were aligned using ClustalW, and phylogenetic inferences were obtained using Bayesian phylogenetic analysis with TOPALi 2.5 software (Biomathematics and Statistics Scotland, Edinburgh, UK) within the integrated Maximum Likelihood application using the K81uf + I + Г model. Numbers at the nodes are percentages of bootstrap values obtained by repeating the analysis 100 times to generate a majority consensus tree. Bootstrap values below 80 were deleted from the final tree. The final set includes 200 base pairs. The new Bartonella sequence described in this study is written in red.

Fig 6. A consensus concatened phylogenetic tree showing the relationships of the Bartonella species studied based on a concatened sequence of Bartonella rpoB, ftsZ and gltA gene fragment.

Concatenated rpoB, ftsZ and gltA sequences were aligned using CLUSTALW and phylogenetic inferences obtained using Bayesian phylogenetic analysis [Ronquist F, Huelsenbeck JP. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bio-informatics 2003; 19:1572–1574] with the TOPALi 2.5 software (Biomathematics and Statistics Scotland, Edinburgh, UK) with the integrated MrBayes application [ttp://mrbayes.csit.fsu.edu] with the HKY+I+Г substitution model. GenBank accession numbers are indicated at the beginning. Numbers at the nodes are bootstrap values obtained by repeating the analysis 100 times to generate a majority consensus tree. There were a total of 1245 positions in the final dataset. The scale bar indicates a 10% nucleotide sequence divergence.