They also looked at the genetic lineage of the Mycobacterium tuberculosis bacteria infecting the patients. 他們還研究了感染患者的結核分枝桿菌的遺傳世系。
It could also be caused by genetic differences between M. tuberculosis populations in different parts of the world, she adds. 她還說，這也可能是由於世界不同地方的結核分枝桿菌種群的遺傳差異造成的。
