1) Bacteria family 2) Family rickettsiaceae 
The Rickettsiaceae are a family of bacteria. The genus Rickettsia is the most prominent genus within the family. It is from this family that the bacteria that eventually formed the mitochondria (an organelle in Eukaryotic cells) is believed to have originated. Most human pathogens in this family are in genus Rickettsia. They spend part of their li...
A family of small, gram-negative organisms often parasitic in man and other animals, causing diseases that may be transmitted by invertebrate vectors. ... (12 Dec 1998) ... 
(rĭ-ket″se-a´se-e) a family of bacteria of the the order Rickettsiales.
[n] - microorganism resembling bacteria inhabiting arthropod tissues but capable of causing disease in vertebrates
family Rickettsiaceae noun microorganism resembling bacteria inhabiting arthropod tissues but capable of causing disease in vertebrates