Rickettsiae as organisms.

Although most pathogenic rickettsiae are obligate intracellular parasites, it is clear that they are bacteria. As such, form and function in rickettsiae are closely similar to form and function found in their free-living counterparts. This review of rickettsiae as bacteria portrays the broad similarities of rickettsiae and free-living bacteria, as well as the differences which distinquish one group from the other and one rickettsia from another. Growth characteristics and requirements, ecologic influences, special adaptations, antibiotic susceptibilities and host-parasite relationships will be considered in a broad survey of likenesses and differences displayed by rickettsiae pathogenic to man.