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Using PCR and an automated laser fluorescent DNA sequencer, we amplified and sequenced a 1,234-bp fragment of the citrate synthase-encoding gene (gltA) of 28 bacteria belonging to the genus Rickettsia. Comparative sequence analysis showed that most of the spotted fever group (SFG) rickettsiae belonged to one of two subgroups. The first subgroup included(More)
We describe the characterization of a novel Rickettsia species cultivated from Dermacentor ticks collected in Russia and France, for which we propose the name Rickettsia raoultii sp. nov. Using multigene sequencing, we demonstrated that five rickettsial isolates from Dermacentor silvarum, Dermacentor reticulatus, Dermacentor marginatus and Dermacentor(More)
Pathogenic Rickettsia species are Gram-negative, obligate intracellular bacteria responsible for the spotted fever and typhus groups of diseases around the world. It is now well established that a majority of sequelae associated with human rickettsioses are the outcome of the pathogen's affinity for endothelium lining the blood vessels, the consequences of(More)
BACKGROUND Manipulation of host cell death is an important determinant of the outcome of an infection. Here, we investigate whether Rickettsia rickettsii-infected host endothelial cells resist the effects of staurosporine, a potent inducer of apoptosis, and we explore the mechanisms underlying the anti-apoptotic effect of infection. METHODS Human(More)
Dermacentor nuttallii from Siberia, Rhipicephalus sanguineus from Crimea, and Rh. pumilio from the Astrakhan region were infected with Rickettsia sibirica (12%), R. conorii (8%), and the Astrakhan fever agent (3%), respectively. Three new Rickettsiae of the R. massiliae genogroup were identified in ticks by 16S rDNA, gltA, and ompA sequencing.
In order to investigate human-louse phylogeny, we partially sequenced two nuclear (18S rRNA and EF-1 alpha) and one mitochondrial (COI) genes from 155 Pediculus from different geographical origins. The phylogenetic analysis of 18S rRNA and EF-1 alpha sequences showed that human lice were classified into lice from Sub-Saharan Africa and lice from other(More)
Vascular endothelial cells (ECs) lining the blood vessels are the preferred primary targets of pathogenic Rickettsia species in the host. In response to oxidative stress triggered by infection, ECs launch defense mechanisms such as expression of heme oxygenase-1 (HO-1). Previous evidence from an established animal model of Rocky Mountain spotted fever also(More)