I don't know. My Catholic gut says it arose with "Do penance, and be baptized every one of you in the name of Jesus Christ, for the remission of your sins: and you shall receive the gift of the Holy Ghost". This sweeping "every one of you" suggests more than personal sin to be wiped clean with baptism. But I understand that you are looking for patristics.
Where do you get "Do Pennance" from metanoeō ?
"But I understand that you are looking for patristics."
Indeed I am as I have yet to find any indication in the East that Baptism does something other than bring us into The Church, forgive our sins and make us "new" in Christ and when they say these things they seem to be presuming that since the Resurrection, membership in The Church is the sine qua non of theosis and it is within The Church that our restored potential for theosis must be pursued. Of course they don't speak of Original Sin, but I didn't expect them to. They do teach that through baptism we die with Christ and our descent into the water is a type of His descent to hades and our rising up out of the water like His Resurrection and thus we are thereby purified of our sins to that point. I think Orthodoxy would say that it is the Sacrifice on the Cross, the descent to the dead and the Resurrection which took care of any "spiritual death" effects steming solely from the Sin of Adam.