SECULAR TRENDS IN NOSOCOMIAL BLOOD-STREAM INFECTIONS IN A 55-BED CARDIOTHORACIC INTENSIVE-CARE UNIT

Background. Although bloodstream infections (BSIs) occur more frequent ly in intensive care unit patients than in ward patients, most studies of nosocomial BSIs in critically ill patients have not distinguished between intensive care unit populations beyond surgical, medical, and pediatric patients. Methods. The primary objective of this study was t o characterize the secular trends in rates of nosocomial BSIs for all pathogens among patients admitted to a busy cardiothoracic intensive c are unit in a single tertiary care institution between January 1986 an d December 1995. Patients with nosocomial BSIs were identified through continual prospective surveillance. Results. A total of 40,207 patien ts were admitted to the cardiothoracic intensive care unit during the 10-year study period, and 804 episodes of nosocomial BSIs among 681 pa tients were identified. The mean crude BSI infection rate was 6.0 per 1,000 patient-care days and increased linearly during the study period (range, 4.4 to 8.1 per 1000 patient-care days), and approached statis tical significance (p value = 0.07). The most common organisms causing BSIs were Staphylococcus aureus (12%), coagulase-negative staphylococ ci (11%), Candida albicans (11%), Pseudomonas aeruginosa (10%), and En terococci (9%). The leading sources of nosocomial BSIs were primary BS Is (33%), intravascular devices (27%), lower respiratory tract infecti ons (17%), and surgical wound infections (12%). The etiologic fraction or the proportion of deaths in cardiothoracic intensive care unit pat ients with BSIs was 15-fold higher than those patients without BSIs (3 7% versus 2.5%, p < 0.001). Conclusions. Rates of nosocomial BSIs amon g patients in our cardiothoracic intensive care unit have increased li nearly during the past decade and patients with nosocomial BSIs have a n increased risk of in hospital mortality. (C) 1998 by The Society of Thoracic Surgeons.