Nosocomial bloodstream infection from abdominal origin in a general ICU: microbiological factors influencing outcome

Purpose and methods

A retrospective (January 1992–December 2000) cohort study was performed in order to identify microbiological factors associated with bad outcome in ICU patients with nosocomial bloodstream infection (BSI) from abdominal infection (n = 96).

Results

During the study period, 1071 episodes of nosocomial BSI were found in 29,727 patients admitted to the ICU. In 91 patients, 143 BSI were found originating from an abdominal source. In patients with multiple episodes only the first was considered for the outcome analysis. Mean (± SD) age of the patients was 54 (± 16.1). APACHE II scores averaged 24 (± 9.5). The median length of ICU stay prior to the BSI was 6 days and the total ICU stay 20 days. The inhospital mortality was 57.2%. In 25 patients the BSI was polymicrobial (27.5%). The causative microorganisms and respectively associated mortality rates were: Gram-negative bacteria (n = 64; 59.4%), E. coli (n = 20; 60.0%), Enterobacter spp. (n = 11; 63.6%), P. aeruginosa (n = 9; 66.7%), Klebsiella spp. (n = 9; 44.4%), Acinetobacter spp. (n = 8; 37.5%), other Gram-negatives (n = 12; 75.0%), Gram-positives (n = 30; 50.0%), coagulase-negative Staphylococci (n = 11; 45.5%), Enterococci and Streptococci (n = 16; 50.0%), S. aureus (n = 6; 50.0%), Candida spp. (n = 9; 77.8%) and anaerobe bacteria (n = 6; 50.0%). No type of microorganism was associated with a statistically significant higher mortality (P > 0.05). In 39.6% of BSI the microorganism involved was antibiotic resistant. In Table 1, microbiological factors are compared for hospital survivors and nonsurvivors. Also in a multivariate analysis no microbiological factor could be recognised as independently associated with mortality (P > 0.05).

Table 1 -

Conclusion

In our cohort of ICU patients with nosocomial BSI from abdominal origin, microbiological characteristics of the infection seem not to affect the outcome.