which of the following grows outside host cells?
Put the following steps of Koch's postulates in order: a. The suspected infectious agent must be isolated and grown outside the host. b. The suspected infectious agent causes the disease when it is introduced to a healthy, experimental host. c. The suspected infectious agent must be found in every case of the disease.
Study of obligate pathogens is difficult because they cannot usually be reproduced outside the host. However, in 2009 scientists reported a technique allowing the Q-fever pathogen Coxiella burnetii to grow in an axenic culture and suggested the technique may be useful for study of other pathogens.