Clustering of enterococcal infections in a general intensive care unit

This is a retrospective study comparing patients' characteristics, antibiotic consumption and environmental contamination before the impact of a new regimen of intensified infection control measures in a general intensive care unit (ICU) at a university-affiliated tertiary-care teaching hospital. The new regimen consisted of (1) reorganization of patient rooms (2) improved hygienic measures including strict hygiene barrier nursing (3) more isolated patient care and (4) more restrictive use of antibiotics. The regimen was introduced after a cluster of enterococcal infections. All patients admitted to the ICU from 1 March 1995 to 28 february 1997 were included. A study period of 12 months after reorganization of the ward was compared with the 12 months immediately before it. The antibiotic consumption, the individual patient's severity of disease (APACHE score), and the extent of therapeutic interventions (TISS score) were recorded. Enterococci were typed biochemically, antibiograms were established and the relation between the isolates was investigated with pulsed-field gel electrophoresis. The bacteriological results and the patient data suggested a hospital-acquired spread as the cause of the ICU enterococcal outbreak. After implementation of the new regimen, we observed a reduction in the rate of enterococcal bloodstream infections from 3.1 to 1.8%. The consumption of antibiotics fell from 6.11 to 4.24 defined daily doses per patient. The introduction of strict hygiene and barrier nursing, more restrictive use of antibiotics, isolation of infected patients, thorough cleaning and disinfection of the unit was followed by an absence of enterococcal infection clustering and reduction in incidence of enterococcal bacteraemia. We were not able to determine whether the reduction in antibiotic consumption was due to the intervention programme.