import re

item = '"last_name,""first_name"",""middle_name"",""birthday"",""passport_series"",""passport_number"",""mfo_name"",""created_at"",""status"""'
regex = re.compile(r'(?<!"),""')
tmp = '""' + regex.sub('"",""', item.strip('"')) + '""'
print(tmp)