Background: Clinical and demographic characteristics of patients, their interaction with pathogens and antimicrobial therapies are prompting changes in the epidemiology of hospital-acquired infections (HI). The knowledge of the etiology of hospital-acquired infections is valuable for the treatment of infected patients and for the prevention of HI.
Patients and method: We analyzed a series of 10 annual prevalence studies during the period 1990-1999 (EPINE project) in Spanish hospitals. Estimate of prevalence of infection was calculated by means of the percent distribution of every organism regarding overall identified organisms and infections.
Results: 40,550 HI were identified among 484,013 patients (HI prevalence = 8.4%; 95% CI, 8.3-8.5%). Gram-positive organism predominated steadily in bloodstream and surgical wound infections, while gram-negative bacilli predominated in respiratory and urinary tract infections. There was an increase in HI infections by Acinetobacter baumannii (from 1.9% in 1990 to 3.6% in 1999; P < 0.001) and Candida albicans (from 2.4 to 3.2%; P < 0.001), as well as an increase in both HI and community-acquired infections by methicillin-resistant Staphylococcus aureus [HI: from 4.7 to 40.2% (P < 0.001); community-acquired: from 2.7 to 15.6% (P < 0.001)].
Conclusions: We observed some changes in the etiology of infections over the last decade: rates of methicillin-resistant S. aureus hospital-acquired and community-acquired infections increased steadily and their initial rates multiplied by 8 and 6, respectively. Rates of HI caused by yeasts and A. baumannii increased also.