Nosocomial pneumonia and bacteremia in intensive care: results from the Belgian national surveillance, 1996-1998

In 1996 the Scientific Institute of Public Health — Louis Pasteur (IPH), in collaboration with the Belgian Society of Intensive Medicine and Emergency Medicine, started a multicentre surveillance of intensive care units (ICU) acquired pneumonias and bacteremia. From January 1996 to June 1998, 60% of Belgian acutecare hospitals (n = 101) participated during at least one surveillance period (3 months), and 64% of those participated more than one period. A total of 31 374 patients were included for the analysis.

In 4.7% (95% CI 4.5—5.0) of the patients a pneumonia with onset later than 48 h of ICU stay and matching CDC criteria for nosocomial pneumonia was registered. In 89% of those at least one ventilation-day had preceded the onset of the infection (RR 10.4%; 8.9—12.2). The number of ventilator-associated pneumonias per 1000 ventilation-days was 19.0/1000 ventilation-days, varying from 11.9 in coronary surgery patients to more than 25 in patients having undergone neurosurgery, non-cardiac thoracic surgery, vascular surgery and transplantation. The predominant micro-organisms were Pseudomonas aeruginosa (recovered in 18.0% of the episodes), Staphylococcus aureus (17.7%), Escherichia coli (12.6%), Candida spp. (12.1%) and Enterobacter spp. (9.5%).

Bacteremia was reported in 2.4% of the patients. Five percent of bacteremia occurred within the first 48 h. Forty percent (n = 301) were secondary to another infection site and 55% (1.3% of the patients and 2.3 BSIs per 1000 patient-days) matched the CDC case definition of laboratory-confirmed primary bacteremia. The device-adjusted primary bacteremia rate was 3.1/1000 catheter-days and varied between 1.5 in coronary surgery to 4.8 in patients with multiple trauma and 6.0 in neurosurgical patients. The five predominant micro-organisms in primary bacteremia were Staphylococus epidermidis (in 33.3% of the episodes), Staphylococcus aureus (12.8%), Enterococcus faecalis (7.1%), Pseudomonas aeruginosa (6.1 %) and Enterobacter aerogenes (5.7%).

The frequent participation to the national surveillance led to an important national database that allows to study the risk factors of ICU-acquired infections, to identify areas for prevention and to improve the inter-ICU comparability of infection rates according to the risk profile of the different ICU populations. International comparisons remain a delicate matter by lack of internationally standardised surveillance methods.