Clinical outcome and microbial flora in patients with secondary and tertiary peritonitis

BACKGROUND: Tertiary peritonitis is defined as a severe recurrent or persistent intra-abdominal infection after adequate surgical source control. Aim of the study was to compare clinical outcome and microbial flora of patients with secondary and tertiary peritonitis. METHODS: A retrospective study was conducted between January 2001 and November 2002. Among 118 patients with severe abdominal infections, 43 patients with a positive microbiology were investigated. The Mannheim Peritonitis Index (MPI) score was recorded at the time of operation. RESULTS: Secondary peritonitis was detected in 20 patients (46.5%) and tertiary peritonitis in 23 patients (53.5%). Mean ICU stay was 18.6 days and mean hospital stay 35.5 days. 100 laparotomies including reoperations were carried out at a follow-up of 38 months. MPI scores in patients with tertiary peritonitis (30.4 ± 8.3) were significantly higher than in patients suffering from the secondary form (24.4 ± 8.0; p < 0.025). Mortality in patients suffering from tertiary peritonitis reached 30.4%. Cardiac co-morbidities (p < 0.035) and fungal infections (p < 0.015) were significantly associated with higher mortality rates. Gram negative and anaerobic isolates in patients with secondary peritonitis were joined or even replaced by fungal and gram positive organisms such as Enterococcus faecalis, faecium and Candida. CONCLUSIONS: In our cohort co-morbidities and microbial isolates were insufficient predictors of tertiary peritonitis and fatal outcome. However, cardiac diseases and fungal organisms correlated with higher mortality. The Mannheim Peritonitis Index can successfully assess and compare patients with different prognoses and therapeutic strategies.