Cardiopulmonary Bypass Time Predicts Early Postoperative Enterobacteriaceae Bloodstream Infection

Background A bloodstream infection in patients undergoing cardiovascular operations is crucial because it can result in significantly worse outcomes. However, microbiological patterns have rarely been investigated in these patients. Methods We retrospectively reviewed the data of 1,041 adult patients who underwent cardiovascular operations using cardiopulmonary bypass from January 2013 to December 2017 at the National Cheng Kung University Hospital, Tainan, Taiwan. The microbiological pattern and associated variables were analyzed in patients with early postoperative primary bloodstream infection. Results Primary bloodstream infection developed in 28 patients (2.7%) within 7 days after cardiovascular operations using cardiopulmonary bypass. In patients with early primary bloodstream infection, 36 microorganisms were isolated, and a gram-negative bacillus was identified to be the predominant pathogen (28 of 36 [77.8%]). The most common microorganisms comprised the Enterobacter (n = 8) and Acinetobacter (n = 7) species, and 16 of the 28 gram-negative bacilli belonged to the Enterobacteriaceae family. Compared with those without postoperative bloodstream infection, patients with Enterobacteriaceae family–related early postoperative bloodstream infections had a significantly longer cardiopulmonary bypass time and also worse early and late survival rates. Conclusions Most patients with early primary bloodstream infection after cardiovascular operations using cardiopulmonary bypass were infected with gram-negative bacilli, and the Enterobacteriaceae family was the most common microorganism observed. Endogenous bacterial translocation after prolonged cardiopulmonary bypass is a possible mechanism of Enterobacteriaceae family–related early primary bloodstream infection in these patients. Prophylactic use of an antibiotic regimen with broader gram-negative bacteria coverage in cardiovascular surgical patients with prolonged cardiopulmonary bypass should be considered.