[Epidemiologic study of pathogens causing nosocomial infections].

Nosocomial infection is a global problem. It significantly adds to the expected duration of hospitalization resulting with an increased economic burden and represents a leading cause of death. The characteristics of nosocomial infection vary from country to country and also changes with time. In order to understand the pathogens causing nosocomial infection in the large teaching hospital in Taiwan, we collected and analysed the surveillence data of nosocomial infection at the National Taiwan University Hospital from 1981 to 1989. We found that the nosocomial infection rate had been around 4-5% annually since 1981 till 1989. As ranked according to the site of infection, surgical wound infections were the most common, followed by the urinary tract, respiratory tract, and blood stream infections. However, the incidence of surgical wound infections had decreased gradually. About one third of nosocomial infections were caused by multiple microorganisms. The most frequently isolated pathogen has changed from Escherichia coli in early years to Pseudomonas aeruginosa in the most recent years. Gram-negative aerobic bacteria has been the major pathogens resulting in nosocomial infections for the past 9 years, accounting for 55-66%. In contrast, fungi have increased rapidly from 1.8% of total isolates in 1981 to 7.7% in 1989. Gram-positive cocci have also increased in recent years. The leading pathogen by infection site was P. aeruginosa in surgical wound infections, E. coli in urinary tract infections, and P. aeruginosa in respiratory tract infections. In earlier years E. coli was the major isolate in bacteremic cases, but glucose non-fermenters, including P. aeruginosa, Acinetobacter calcoaceticus and others, plus Enterobacter species-emerged as the major pathogens of recent years.(ABSTRACT TRUNCATED AT 250 WORDS)