Diplorickettsia massiliensis species is an obligate intracellular, gram negative bacterium isolated from Ixodes ricinus ticks collected in Slovak republic forest geographically from southeastern part of Rovinka in 2006.

[1][2] Because of its low 16S rDNA similarity (94%) with R. grylli, it was classified as a new genus Diplorickettsia into the family Coxiellaceae and the order Legionellales.

The evidence of infection was further reconfirmed by using PCR-assay, thus established its role as a human pathogen and later whole genome sequencing was performed.

This isolate has been deposited in the collection of the two World Health Organization Collaborative Centers for Rickettsial Reference and Research in Bratislava, Slovak Republic and the Faculté de Médecine, University of the Mediterranean in Marseille, France, as well as in the German Collection of Microorganisms and Cell Cultures (Deutsche Sammlung von Mikroorganismen und Zellkulturen, DSMZ) under the reference DSM 233381.

Comparative 16S rRNA gene sequence analysis showed that this strain belongs to the family Coxiellaceae, order Legionellales of Gamma-proteobacteria, and the closest relatives are different Rickettsiella spp.

[5] The presence of these CSIs molecularly distinguishes this clade from other members of the family Coxiellaceae, further supporting the combination of the genera Rickettsiella and Diplorickettsia.

[citation needed] Additionally, three CSIs were identified as uniquely shared between Diplorickettsia, Rickettsiella and Coxiella, another genus belonging to the family Coxiellaceae.

[5] Bacteria visualized in a rich culture established in XTC-2cell line by Gimenez staining appeared as intracellular red rods usually grouped in pairs but not connected with each other.

A cytopathogenic effect, including cellular layer detachment and cell disruption, was observed 3–5 days after inoculation.

[citation needed] Multiple attempts at cultivation of the bacteria in solid axenic media (both common and Legionella-specific) were not successful.

Unlike other intracellular bacteria, including rickettsiae, 20B strain failed to highlight surface glycoproteins when colored with ruthenium red.