How many nosocomial infections are missed if identification is restricted to patients with either microbiology reports or antibiotic administration?

OBJECTIVE: To investigate how many nosocomial infections would be missed if surveillance activities were restricted to patients having either microbio logy reports or antibiotic administration. DESIGN: Analysis of data from a large prevalence study on nosocomial infect ions (Nosocomial Infections in Germany-Surveillance and Prevention). SETTING: A total of 14,966 patients were investigated in medical, surgical, obstetric-gynecologic, and intensive-care units of 72 German hospitals rep resentatively selected according to size. Five hundred eighteen patients (3 .5%) had at least one nosocomial infection. Microbiology reports were avail able for 56.6% of these patients on the prevalence day, and 86.3% received antibiotics. RESULTS: Only 31 nosocomially infected patients (6%) would have been missed by using either microbiology reports or antibiotic treatment as an indicat or. These indicators of nosocomial infections had a high diagnostic sensiti vity for nosocomial pneumonia (98.8%), urinary tract infections (96.3%), an d primary bloodstream infections (95.3%), but a lower sensitivity for wound infections (85.4%). Thus, 97.4% of all nosocomial infections were found wi th this method in intensive-care units and 96.1% in medicine units, but onl y 89.7% in surgical departments. In 9 (12.5%) of 72 hospitals, the overall sensitivity would have been <80% using a combination of the two indicators. For this reason, the situation in one's own hospital should be checked bef ore using this method. CONCLUSIONS: After checking the situation in one's own hospital, the "eithe r-or" approach using the two indicators "microbiology report" and "antibiot ic administration" can be recommended as a time-saving measure to diagnose pneumonia, urinary tract, and primary bloodstream infections. For wound inf ections, additional information obtained by changing dressings or participa ting in ward rounds is necessary to achieve satisfactory sensitivity in the surveillance of nosocomial infections. Of course, it is necessary that the surveillance staff discard all false positives to ensure a satisfactory sp ecificity (Infect Control Hosp Epidemiol 1999;20:124-127).