Impact of Remote Cholecystectomy on Clinical Outcomes Following Pseudomonas aeruginosa Bloodstream Infection.

Background: Mortality associated with Pseudomonas aeruginosa bloodstream infection (PABSI) remains high despite advances in clinical care and therapeutics. In a recent study using a mouse model of PABSI, the gallbladder was identified as a reservoir for bacterial expansion. Furthermore, bile exposure has been linked to increased antimicrobial resistance. Therefore, we asked whether patients with retained gallbladders might experience more antimicrobial-resistant PABSIs, extended culture positivity, and worsened clinical outcomes. Methods: We conducted a retrospective cohort study of adults hospitalized over a 5-year period with PABSI. PABSI cases were defined as patients with ≥1 positive P. aeruginosa bacterial culture from the blood. Patients were categorized as those retaining a gallbladder (no cholecystectomy) or not (cholecystectomy). Cholecystectomy was defined as a history of cholecystectomy ≥1 year prior to the index episode of PABSI. Inferential statistics were used to identify associations between remote cholecystectomy and antimicrobial resistance profile, length of blood culture positivity, and in-hospital and 90-day mortality. Results: The overall study population included 336 patients: 262 (78%) with a retained gallbladder and 74 (22%) without. Using the entire study population and a matched cohort, we observed no difference in length of culture positivity, 90-day mortality, or in-hospital mortality between groups based on the presence of a gallbladder. Overall, composite 90-day mortality was 30.1%, which was similar to a prior investigation of PABSI outcomes at our institution. While the presence of a gallbladder did not affect the outcome, patients with PABSI and liver disease had significantly higher 90-day mortality than those without liver disease. Furthermore, no robust differences were observed in the antimicrobial resistance profile of P. aeruginosa isolates from the group with or without a gallbladder. Conclusions: In our study, neither PABSI antimicrobial resistance pattern nor clinical outcomes were affected by remote cholecystectomy. However, we do demonstrate that mortality for patients with PABSI in the modern era remains high despite advances in antipseudomonal therapeutics.