Enterococci increase the morbidity and mortality associated with severe intra-abdominal infections in elderly patients hospitalized in the intensive care unit

OBJECTIVES: Enterococci may increase morbidity and mortality in elderly patients with intra-abdominal infections (IAIs) hospitalized in the intensive care unit (ICU). PATIENTS AND METHODS: A single-centre, retrospective evaluation of an ICU database (1997-2007) of elderly ICU patients (≥75 years) with a severe IAI was performed. Demographics, severity scores, underlying diseases, microbiology and outcomes were recorded. Patients with enterococci isolated in peritoneal fluid (E+ group) were compared with those lacking enterococci in peritoneal fluid (E- group). Stepwise multivariate logistic regression was used to identify independent factors associated with mortality. RESULTS: One hundred and sixty patients were included (mean ± SD age 82 ± 5 years; n = 72 in the E+ group). The E+ group was more severely ill than the E- group, with higher Simplified Acute Physiologic Score 2 (61 ± 20 versus 48 ± 16, P = 0.0001) and Sequential Organ Failure Assessment scores (8 ± 3 versus 5 ± 3, P = 0.0001), a greater postoperative infection rate (58.3% versus 34.1%, P = 0.01), a higher incidence of inappropriate empirical antimicrobial therapies (33.3% versus 19.3%, P = 0.04), a longer duration of mechanical ventilation (11.8 ± 10.9 versus 7.8 ± 10.2 days, P = 0.02) and greater vasopressor use (7.2 ± 7.1 versus 3.3 ± 4.1 days, P = 0.001). ICU mortality was higher in the E+ group than in the E- group (54.2% versus 38.6%, P = 0.05). In the multivariate analysis, E+ status was independently associated with mortality (odds ratio 2.24; 95% confidence interval 1.06-4.75; P = 0.03). CONCLUSIONS: In severely ill, elderly patients in the ICU for an IAI, the isolation of enterococci was associated with increased disease severity and morbidity and was an independent risk factor for mortality.