How to survey nosocomial infections.

Many surveillance methods for nosocomial infections (NIs) have been put forward in the literature, and all have their advantages and disadvantages. Different surveillance methods are useful, depending on whether the objective of surveillance is only to increase sensitivity to infection control problems and to identify areas with possible infection control problems; to confirm a possible infection control problem through comparison with other units or departments; or to use surveillance data for identifying the sources of infections. Furthermore, time effectiveness is a major point in selecting the most appropriate method, particularly the method for case identification. In units or departments with a high level of NI, even highly time-consuming surveillance methods may be ultimately time-effective; in units or departments with a lower level of NI, the time-effectiveness depends on the time necessary for case identification. Close liaison with staff in the units is a sine qua non for the success of all surveillance activities.