Abstract: Disclosed are methods and devices for continuous in vivo monitoring of a potential infection site. Disclosed devices may be utilized to alert patients and/or health care providers to the presence of a pathogen at an early stage of a hospital acquired infection, thereby providing for earlier intervention and improved recovery rates from bacterial infection. Disclosed methods utilize implantable devices for location at an in vivo site. The implantable device is held in conjunction with an optical fiber that detects and transmits an optically detectable signal generated in the presence of a pathogen. Upon generation of the emission, the optically detectable emission signal may be transmitted to a portable detection/analysis device. Analysis of the characteristics of the emission signal produced may be used to determine the presence or concentration of pathogens at the site of inquiry, following which real time information may be transmitted to medical personnel, for instance via a wireless transmission system.