The results of a study on the incidence of nosocomial infections in a 1800 bed University hospital .are reported. Tl~e study, carried out over a 9 months period, included: 1) continuous microbiological surveillance, and 2) a clinical and epidemiological survey. On ihe basis of the microbiological data collected and analyzed by a computer data system, developed and employed for the control of nosocomial infections, a aveekly bed-to-bed survey ~vas carried out by the staff of the Institute of Infectious Diseases. Among 2777 suspected nosocomial infections, as revealed by microbiological monitoring, 701 were confirmed after the bed-to-bed survey. The nosocomial infection rate was 6.75 per I00 discharges. It was t~igher 'in the surgical than in the medical ~ards (7.3 and 6 per 100 discharges, respectively).
Nosocomial urinary tract infections were the most frequent (74.2%). The urinary infection rate was higher in the surgical than in the medical wards (5.3 and 4.6 per 100 discharges, respectively).
Escherichia coil (19.4%), P s e u d o m o n a s aeruginosa (19.3%), Proteus spp. ('18.4%) were the pathogens most frequently associated with nosocomial infections. They were fotlowed by KIebsieIIa p n e u m o n i a e (7.8%) and S t a p h y l o c o c c u s aureus (6.5%) in frequency.
Among the risk factors, involved in nosocomial infections, the importance of catheterization was confirmed: among our patients with nosocomial urinary tract infections, 73.4% and 79.5% --in the medical and surgical wards, respectively --underwent urological instrumentation, mainly catheterization.
An analogous and more detailled study is now in progress and will be extended in the next years.