Complex sentence: Bacillary angiomatosis (BA) is a bacterial infection caused by either "Bartonella henselae" or "Bartonella quintana".
Split into simpler sentences: Bacillary angiomatosis (BA) is a form of angiomatosis associated with bacteria of the Bartonella genus. It is caused by either "Bartonella henselae" or "Bartonella quintana".