Clinical characteristics and prognosis of bacteraemia during postoperative intra-abdominal infections

Bloodstream infections of abdominal origin are usually associated with poor prognosis. We assessed the clinical and microbiological characteristics of critically ill patients admitted to the intensive care unit (ICU) for postoperative intra-abdominal infection (PIAI) and analysed the influence of bacteraemia on their outcome.

All consecutive PIAI patients admitted to the ICU between 1999 and 2014 were prospectively analysed. Bacteraemic patients (at least one positive blood culture in the 24 h preceding/following surgery) were compared with non-bacteraemic patients. Demographic characteristics, underlying disease, severity scores at the time of reoperation, microbiological results, therapeutic management, outcome, and survival were recorded. Results are expressed as median (interquartile range (IQR)) or proportions.

Overall, 343 patients (54% male, 62 (49-73) years old) with PIAI were analysed, including 64 (19%) bacteraemic patients. Immunosuppression and cancer were more frequent in bacteraemic patients (p < 0.001 in both cases). No difference between groups was observed for the characteristics of initial surgery. Time to reoperation, site, and cause of PIAI were similar in both groups. At the time of reoperation, Sequential Organ Failure Assessment (SOFA) score was higher in bacteraemic patients (8 (6-10) versus 7 (4-10); p < 0.05). A predominance of Gram-positive (34%) and Gram-negative (47%) bacteria were recovered from blood cultures (polymicrobial bacteraemia in 9 (14%) patients and bacteraemia involving multidrug-resistant organisms in 14 (22%) patients). In multivariate analysis, risk factors for bacteraemia were immunosuppression or cancer, high SOFA score, and E. coli in peritoneal samples. Bacteraemia did not impact the management (with similar results for the adequacy of antibiotic therapy, anti-infective agents used, de-escalation or duration of therapy in both groups). Neither hospital mortality nor morbidity criteria differed between groups. Risk factors for mortality in multivariate analysis were urgent initial surgery, high Simplified Acute Physiology Score (SAPS) II score and documented antifungal therapy, but not perioperative bacteraemia.

In this ICU population, bacteraemia did not change the overall management of patients with PIAI. Our data suggest that bacteraemic patients do not require a specific management.