Retrospective analysis of nosocomial infections in an Italian tertiary care hospital.

Nosocomial infections are one of the leading causes of morbidity and mortality in hospitalized patients. Studies of their prevalence in single institutions can reveal trends over time and help to identify risk factors. The aim of this study was to investigate the nosocomial infections trend and identify the prevalence of predominant bacterial microorganisms and their drug resistance patterns in an Italian tertiary care hospital. Infections were classified according to the Centres for Disease Control and Prevention definitions. A retrospective study was carried out from March 2011 to June 2014, based on the bacterial isolate reports of a hospital located in Central Italy. During the 40-month study period, a total of 1547 isolates were obtained from 1046 hospitalized patients and tested for their antibiotic sensitivity. The most common isolates belonged to the Enterobacteriaceae family (61.7%), followed by Enterococcus species (12.4%), Pseudomonas species (10.7%) and S. aureus (10.0%). The incidence density rate of nosocomial infections was 7.4 per 1000 patient days, with a significant difference among the 3 annual infection rates (P<0.001). The highest infection prevalence rate was found in Internal Medicine Unit (41.3%), followed by Intensive Care Units (12.4%), Surgical Units (9.0%,) and Cardiology (7.1%).