MicrobeWorld

Surprise! Coxiella burnetii, the agent of Q fever, has been grown in cell-free media. This is news because, along with rickettsiae and a few others, C. burnetii is the stereotypical obligate intracellular bacterial parasite. Until now, coxiellae could only be grown within a host or in host cells in culture. So how did researchers at the NIH's Rocky Mountain Laboratory come up with a complex—but otherwise fairly ordinary—laboratory medium that supports their growth? It wasn't just trial-and-error, as you might suppose.