Epidemiological trends of emerging organisms and antimicrobialresistance in Italian ICUs: risk adjusted rates from the SPIN-UTI project

Objectives: The main aims of our study were to compare risk adjusted rates from the first two editions of the SPIN-UTI, Italian Nosocomial Infections (NIs) Surveillance in Intensive Care Units (ICUs), project and to follow up epidemiological time-trends of nosocomial pathogens, emerging organisms and their antimicrobial resistance patterns. Methods: The SPIN-UTI methodology is based on the HELICS-ICU protocol (version 6.1, 2004) (Agodi et al., 2010). Prospective patient-based surveillance was implemented from October 2006 to March 2007 by 49 ICUs in the first edition and from October 2008 to March 2009 in the second one by 28 ICUs. Results: In the first study, the cumulative incidence of ICU-acquired infections for all sites was 19.8 per 100 patients and the incidence density 17.1 per 1000 patient-days. The most frequently reported NI type was pneumonia (PN, 53.6%) followed by bloodstream infections (BSIs, 23.4%), urinary tract infections (UTIs, 16.7%) and catheter-related infections (6.3%). In the second study, the cumulative incidence and the incidence density were 19.9 per 100 patients and 19.0 per 1000 patient-days, respectively. Comparing the proportion of infections by type, a decrease of PN (from 53.6% to 47.3%) and a significant increase of UTIs (from 16.7% to 22.3%; p < 0.000) were shown. In the first edition, bacterial species most frequently detected were: Pseudomonas aeruginosa (19.0%), Staphylococcus aureus (9.4%) and Acinetobacter baumannii (7.5%) (Agodi et al., 2010). In the second, P. aeruginosa remained the most frequently reported micro-organism (16.9%), while the proportion of A. baumannii (14.2%) and K. pneumoniae (9.6%) significantly increased. Trend of resistance rates were as follows: imipenem-resistant A. baumannii revealed no change (76.9% and 77.3%), imipenem-resistant K. pneumoniae increased (from 8.3% to 13.9%), and imipenem-resistant or ciprofloxacin-resistant P. aeruginosa revealed an increase from 40.5% to 48.1% and from 42.7% to 50.6% respectively. Conclusion: Our risk estimates of ICU-acquired PN and BSI reflect the European scenario, as reported by the BURDEN project (Lambert et al., 2010). Furthermore, our study revealed an increasing risk of UTIs as a target for infection control and highlighted the emerging role of A. baumannii and K. pneumoniae in Italy as well as an increasing trend in time of specific resistance patterns. National and international cooperative efforts are needed to prevent NIs in ICUs.