Multispacer Sequence Typing Relapsing Fever Borreliae in Africa

In Africa, relapsing fevers are caused by four cultured species: Borrelia crocidurae, Borrelia duttonii, Borrelia hispanica and Borrelia recurrentis. These borreliae are transmitted by the bite of Ornithodoros soft ticks except for B. recurrentis which is transmitted by louse Pediculus humanus. They cause potentially undifferentiated fever infection and co-infection with malaria could also occur. The exact prevalence of each Borrelia is unknown and overlaps between B. duttonii and B. crocidurae have been reported. The lack of tools for genotyping these borreliae limits knowledge concerning their epidemiology. We developed multispacer sequence typing (MST) and applied it to blood specimens infected by B. recurrentis (30 specimens), B. duttonii (18 specimens) and B. crocidurae (13 specimens), delineating these 60 strains and the 3 type strains into 13 species-specific spacer types. B. crocidurae strains were classified into 8 spacer types, B. duttonii into 3 spacer types and B. recurrentis into 2 spacer types. These findings provide the proof-of-concept that that MST is a reliable tool for identification and genotyping relapsing fever borreliae in Africa

Advanced tools for the diagnosis of relapsing fever borrelioses in Africa

En Afrique, les fièvres récurrentes à Borrelia sont des pathologies négligées transmises par les arthropodes et responsables de septicémie mortelle et d'autres manifestations cliniques, en particulier d'avortement chez les femmes enceintes. Quatre Borrelia différentes sont actuellement cultivées de prélèvements cliniques et de vecteurs, il s'agit de Borrelia crocidurae, Borrelia duttonii, Borrelia recurrentis et Borrelia hispanica. Ces différentes espèces ont été initialement séparées les unes des autres sur la base de leur répartition géographique et de leur vecteur. Au cours de ce travail de thèse, nous avons réalisé le séquençage et l'annotation du génome de Borrelia crocidurae. Ceci nous a permis de comparer le génome de trois espèces séquencées: Borrelia crocidurae, Borrelia duttonii et Borrelia recurrentis. Cette comparaison indique que ces trois espèces sont extrêmement proches comme cela avait déjà été montré par la comparaison de la séquence du gène 16S ARN ribosomal de chacune de ces espèces, montrant une similarité comprise entre 99,7 et 99,9%. L'analyse de données génomiques permet de conforter les résultats antérieurs basés sur l'analyse de quelques gènes et de proposer que ces trois espèces ne forment qu'une seule espèce génomique présentant trois écotypes avec une relative spécificité de vecteur, de répartition géographique et d'évolution clinique. La très grande similitude entre Borrelia crocidurae, Borrelia duttonii et Borrelia recurrentis constitue un obstacle pour la mise au point de techniques de diagnostic direct de ces espèces dans les prélèvements de vecteur ou dans les prélèvements humains.In Africa, relapsing fever borreliae are neglected arthropod-borne pathogens causing mild to deadly septicemia. Borrelia crocidurae, Borrelia duttonii, Borrelia hispanica and Borrelia recurrentis are the currently cultured causative agents in Africa. The relapsing fever borreliae species were initially distinguished one from another on the basis of geography and vector. we performed the genome sequencing of Borrelia crocidurae. At the genomic level the four species are highly similar as illustrated by the 16S rRNA gene sequence of each species, resulting in an overall high sequence similarity of 99.7 to 99.9% between the four species. Genomic analyses of Borrelia crocidurae, Borrelia duttonii and Borrelia recurrentis further indicated that they in fact forming an unique bacterial species, each one of the three species could be regarded as an ecotype of an unique species with preferential arthropod vector, geographic distribution and clinical outcome, rather than an unique bacterial species. The high similarity between species remained an obstacle for the diagnosis at the species level. Currently the identification of relapsing fever borreliae relies upon a few phenotypic traits and the detection of single nucleotide polymorphisms in the 16S rRNA and flabB, glpQ genes and the 16S-23S ribosomal RNA intergenic spacer (IGS). In this study, based on comparative genomic anaylsis between the published genomic sequence and partial sequence in the genbank, we developed multiplex, quantitative real-time PCR detecting any relapsing fever Borrelia and specifically B. crocidurae, B. hispanica and B. duttonii/B. recurrentis

Sex Differences in Fecal Microbiome Composition and Function of Dromedary Camels in Saudi Arabia

The gastrointestinal microbiome plays a significant role in diet digestion and the energy production of its host. Several factors that affect the gastrointestinal microbiota composition were studied in camels. Yet, the impact of sex on the gastrointestinal bacteriome of camels remains unexplored to date. In this perspective, the fecal microbiome community composition from dromedary camels was determined in 10 male and 10 female samples using the 16S rRNA amplicon, in order to estimate if this was influenced by sex. The core microbiome in females contained 284 bacterial OTUs and one archaeal OUT, whereas in males, it contained 279 bacterial OTUs and one archaeal OTU. In females, Bacteroidetes and Spirochaetes were significantly more abundant than in male camels, whereas Lentisphaerae and Euryarchaeota were significantly abundant in males. According to Principal Coordinate Analysis and UPGMA clustering, grouping with respect to sex was observed. The functional prediction results showed differences such as energy production and conversion, and that the cell wall/membrane/envelope were enriched in female camels. The fecal microbiome of male camels was rich in amino acid, lipid transport and metabolism

Low genetic diversity among Francisella-like endosymbionts within different genotypes of Hyalomma dromedarii ticks infesting camels in Saudi Arabia

Background and Aim: Hyalomma dromedarii ticks are vectors of disease agents and hosts of Francisella-like endosymbionts (FLEs). Knowledge about intraspecific genetic variation among H. dromedarii and its Francisella species is limited. The aims of this study were to investigate whether certain H. dromedarii genotypes are specialized in carrying specific Francisella species genotypes and scrutinize the population structure of H. dromedarii ticks in Saudi Arabia. Materials and Methods: We collected 151 H. dromedarii ticks from 33 camels from 13 locations in Saudi Arabia. The second internal transcribed spacer (ITS2), cytochrome c oxidase subunit-1(COI), and 16S rRNA genes were used for single-and multi-locus sequence typing and phylogenetic analyses. H. dromedarii-borne Francisella was screened using the tul4 gene and 16S rRNA Francisella-specific primers followed by amplicon Sanger sequencing. Results: Single-locus typing of ticks using ITS2, 16S rRNA, and COI genes yielded 1, 10, and 31 sequence types (ST), respectively, with pairwise sequence similarity of 100% for ITS2, 99.18-99.86% for COI, and 99.50-99.75% for 16S rRNA. COI sequence analysis indicated a lack of strict geographical structuration, as ST15 was found in both Saudi Arabia and Kenya. In contrast, multilocus sequence typing resolved 148 H. dromedarii ticks into 39 genotypes of ticks and three genotypes of FLEs. The ST2-FLE genotype was carried by the tick genotype ST35, while the ST1-FLE genotype and 41.89% of the ST3-FLE genotype were carried by the tick genotype ST32. Accordingly, there appeared to be no specialization of certain tick genotypes to harbor-specific FLE genotypes. Conclusion: For the 1st time, we have provided an overview of the population structure of H. dromedarii ticks and FLE strains. We found a low level of genetic diversity among FLEs and non-specialized circulation of FLEs among H. dromedarii ticks

Chromosome and Megaplasmid Sequences of Borrelia anserina (Sakharoff 1891), the Agent of Avian Spirochetosis and Type Species of the Genus.

Sequences of the linear chromosome and plasmids of Borrelia anserina, the cause of avian spirochetosis of poultry, revealed a smaller genome than those of other Borrelia spp. transmitted by argasid ticks. Missing or disrupted genes included a dam methylase and those in the pathway for synthesis of phospholipids from glycerol