An Italian woman has been arrested on suspicion of killing her two-year-old daughter whose body was covered in bruises and who died of cardiac arrest after a respiratory crisis despite medics' efforts to save her at Bordighera near Genoa Monday, local sources said.     They said an autopsy may be performed.     The girl's mother said she fell down the stairs.     The woman has been arrested on charges of involuntary manslaughter.     ALL RIGHTS RESERVED © Copyright ANSA