Reproducibility of the Surveillance Effect to Decrease Nosocomial Infection Rates

Objective.To investigate whether the reduction effect due to participation in a nosocomial infection surveillance system for laboratory-confirmed central venous catheter (CVC)-associated primary bloodstream infection (BSI), ventilator-associated pneumonia (VAP), and surgical site infection (SSI) is reproducible for different time periods, independent of confounding factors that might occur during a specific time period.Methods.Data from the German national nosocomial infection surveillance system from the period January 1997 through June 2008 were used. CVC-associated BSI data and SSI data were analyzed for 3 starting periods, and VAP data were analyzed for 2 starting periods. Monthly infection rates were calculated for the following 36 months, and relative risks comparing the first and third surveillance years of each period were calculated.Results.A total of 2,399 CVC-associated BSI cases from 267 intensive care units, 3,637 VAP cases from 150 intensive care units, and 829 SSIs following 3 different procedures from 113 departments were analyzed. A significant reduction in VAP was shown for both starting periods investigated (overall relative risk [RR], 0.80 [95% CI, 0.74-0.86]). A significant reduction in CVC-associated BSI was demonstrated for 2 of 3 starting periods (overall RR, 0.83 [95% CI, 0.75-0.91]). A significant reduction in SSI was found for 2 starting periods for knee prosthesis insertion (overall RR, 0.56 [95% CI, 0.38-0.82]), for all of the 3 starting periods for cesarean delivery (overall RR, 0.75 [95% CI, 0.61-0.93]), and for none of the 3 starting periods for endoscopically performed cholecystectomy (overall RR, 0.89 [95% CI, 0.62-1.27]).Conclusions.The surveillance effect, manifest as a significant reduction of nosocomial infection rates between the first and third years of participation in a surveillance system, was observed independently from the calendar year in which the surveillance activities started.