Disinfecting Cap for Needleless Connectors with Multi-Part Housing and Automatic Lock

A disinfecting cap for a needleless connector includes an outer housing having a sidewall and an outer guide on an inner surface of the sidewall. The cap also includes an inner housing having an open end sized to receive a distal end of the needleless connector, a sidewall, and an inner guide on an outer surface of the sidewall that interacts with the outer guide of the outer housing. The cap also includes an absorbent member disposed in the inner housing configured to contain a cleaning solution for cleaning and/or disinfecting portions of the needleless connector engaged to the cap. Movement of the inner guide relative to the outer guide causes the inner housing to move axially into the outer housing and to alternate between rotating in a first direction and rotating in a second direction relative to the outer housing.