Impact of Remote Cholecystectomy on Clinical Outcomes Following Pseudomonas aeruginosa Bloodstream Infection: A Retrospective Cohort Study

Purpose: Mortality associated with Pseudomonas aeruginosa bloodstream infection (PABSI) remains high despite advances in clinical care and therapeutics. In a recent study using mice to model PABSI, the gallbladder (GB) was identified as a reservoir for bacterial expansion. Furthermore, bile exposure has been linked to increased antimicrobial resistance (AMR). Therefore, we asked whether patients with retained gallbladders might suffer from more antimicrobial resistant P. aeruginosa (Pa) infections, extended culture positivity, and worsened clinical outcomes. Methods: Retrospective cohort study of adults hospitalized over a five-year period with PABSI. PABSI cases were defined as patients with ≥ 1 positive Pa bacterial culture from the blood. Patients were categorized as either those retaining a gallbladder (no cholecystectomy) or those without (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 final study population included 336 patients, 262 (78%) with retained gallbladder and 74 (22%) without. We observed no difference in 90-day or in-hospital mortality between groups. Overall, composite 90-day mortality was 30.1%. Furthermore, no robust differences were observed in the antimicrobial resistance profile of Pa isolates between the groups. Conclusions: In our study, neither PABSI AMR pattern nor clinical outcome was affected by remote cholecystectomy. However, we do demonstrate that mortality for patients with PABSI in the modern era remains high despite advances in anti-pseudomonal therapeutics. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by grants from an American Cancer Society (ACS) Clinician Scientist Development Grant (#134251-CSDG-20-053-01-MPC, awarded to K.E.R.B.), and a Pilot Award from the Northwestern Enterprise Data Warehouse (awarded to L.R.H.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This research study (STU00210641) was reviewed by the Northwestern University Institutional Review Board and was deemed an observational study where no ethical approval was required. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are contained within the manuscript.