rickettsiae

As an adjective bacteria

is bacterial.

As a noun rickettsiae is

.

As nouns the difference between rickettsias and rickettsiae

is that rickettsias is plural of rickettsia while rickettsiae is plural of rickettsia.

As a noun rickettsiae

is plural of rickettsia.

As an adjective rickettsial is

relating to rickettsia.

As nouns the difference between rickettsiae and rickettsia

is that rickettsiae is plural of rickettsia while rickettsia is any of a group of gram-negative bacteria, of the genus Rickettsia, carried as parasites by ticks, fleas and lice; they cause typhus and other diseases.