An apparatus for sterilizing a tubular medical line port, having a cap with an open distal end and a cavity therein which is dimensioned to receive an outer scrubbing member and the medical line port. Outer disinfected-impregnated scrubbing member is coaxially received in the cavity and has a socket therein dimensioned for engaging exterior side surfaces of the tubular medical line port when inserted into the socket for thereby scrubbing exterior surfaces of the port with the scrubbing member by rotating the cap. The outer scrubbing member is axially displacable downwardly in the cavity by insertion of the medical line port therein from an upper position prior to use to a lower position where it is retained to thereby indicate that the apparatus has been used and should not therefore be reused. A reuse prevention insert is also provided in the cavity of the cap and is displacable with the outer scrubbing member from the upper position prior to use to the lower position during and after use. This insert is provided with inwardly protruding teeth that are biased for inward compression and thereby prevent re-access of a medical line port into the socket of the scrubbing member after removal of the medical line port.