After aligning the sequences obtained for the segment of gltA with the corresponding sequences of other Rickettsia species available in GenBank, we determined that all sequences of larvae and nymph ticks belonged to the genus Rickettsia.

The genus Rickettsia contains [approximately equal to]25 validated species of bacteria; another 25 isolates that have not been fully characterized or have not received a species designation have also been described.

To the Editor: Rickettsia raoultii is an obligate intracellular gramnegative bacterium belonging to the spotted fever group (SFG) of the genus Rickettsia. Genotypes RpA4, DnS14, and DnS28, originally isolated from ticks from Russia in 1999 (1), were designated as Rickettsia raoultii sp.

To the Editor: Members of the genus Rickettsia have garnered much attention worldwide in recent years with the emergence of newly recognized rickettsioses.

Bacterial diversity in Amblyomma americanum (Acari: Ixodidae) with a focus on members of the genus Rickettsia. J Med Entomol.

Spotted fever group (SFG) rickettsioses are caused by obligate intracellular gram-negative bacteria of the genus Rickettsia and are transmitted by hematophagous arthropods, mainly ticks.

Diversity of genus Rickettsia detected from ticks in Japan.

To the Editor: The genus Rickettsia consists of obligate intracellular bacteria that cause spotted fever and typhus fever; these bacteria are usually transmitted by an arthropod vector.

Rickettsia felis is a member of the genus Rickettsia, which comprises intracellular pathogens that produce infections commonly called rickettsioses.