The gastrointestinal tract : the undrained abscess of multiple organ failure

This study determined the association between proximal gastrointestinal (GI) colonization and the development of intensive care unit (ICU)-acquired infection and multiple organ failure (MOF) in a population of critically ill surgical patients. ICU-acquired infection in association with progressive organ system dysfunction is an important cause of morbidity and mortality in critical surgical illness. Oropharyngeal and gastric colonization with the characteristic infecting species is common, but its association with ICU morbidity is poorly defined. A prospective cohort study of 41 surgical ICU patients was undertaken. Specimens of gastric and upper small bowel fluid were obtained for quantitative culture; the severity of organ dysfunction was quantitated by a numeric score. One or more episodes of ICU-acquired infection developed in 33 patients and involved at least one organism concomitantly cultured from the upper GI tract in all but 3. The most common organisms causing ICU-acquired infection--Candida, Streptococcus faecalis, Pseudomonas, and coagulase-negative Staphylococci--were also the most common species colonizing the proximal GI tract. Gut colonization correlated with the development of invasive infection within 1 week of culture for Pseudomonas (90% vs. 13% in noncolonized patients, p < 0.0001) or Staphylococcus epidermidis (80% vs. 6%, p < 0.0001); a weaker association was seen for colonization with Candida. Infections associated with GI colonization included pneumonia (16 patients), wound infection (12 patients), urinary tract infection (11 patients), recurrent (tertiary) peritonitis (11 patients), and bacteremia (10 patients). ICU mortality was greater for patients colonized with Pseudomonas (70% vs. 26%, p = 0.03); organ dysfunction was most marked in patients colonized with one or more of the following: Candida, Pseudomonas, or S. epidermidis. The upper GI tract is an important reservoir of the organisms causing ICU-acquired infection. Pathologic GI colonization is associated with the development of MOF in the critically ill surgical patient.