Abstract: An improved catheter is provided comprising a flexible cannula having at least two lumens formed in the entire length of the cannula. A plug seals one end of one of the lumens. One end of a filament is connected to the underside of the plug and the filament extends through the entire length of the lumen. The plug is configured such that by pulling on the other end of the filament the plug is pulled through the lumen to thereby extract a culture sample when the catheter is implanted. A culture sample can be taken to detect the possibility of catheter sepsis, without the need to remove the catheter.