[Hospital infections at the medical Infection Surveillance Unit from 1984 to 1988].

The aim of the present work was to study hospital infection tendencies and to analyze the variations that have occurred in the accumulated incidence, the localization and the responsible microorganisms in a medical ICU of the Hospital Ramón y Cajal, Madrid during a 5 years period. Nosocomial infections appear with a statistically significant decreasing tendency: the simple regression curve, estimated from the monthly accumulated incidence, presents a slope = -0.16 (p less than 0.05); the adjustment made with the annual accumulated incidence values shows a slope = -2.15 (p less than 0.001). The most frequent localization of hospital infections were: lower respiratory tract, urine, and blood. These infections show in general a decreasing tendency existing a statistical difference in respiratory = -1.5 (p less than 0.001) and urinary = -1.48 (p less than 0.001) infections. The microorganisms most frequently isolated in these patients were P. aeruginosa, S. marcescens and E. coli.