Relationship between micro-organisms found in biliary cultures and subsequent surgical site infections after Pancreaticoduodenectomy at three University of the Witwatersrand academic hospitals

Abstract

Introduction Surgical site infections (SSI) are common after pancreaticoduodenectomy. Intra-operative bactobilia is a reported risk factor for septic post-operative complications. In this study, we aimed to study the association between the micro-organisms in intra-operative biliary cultures and subsequent SSI at three University of the Witwatersrand academic hospitals. Methodology In this retrospective observational study, we included all patients who underwent a pancreaticoduodenectomy between January 2014 and December 2019. Demographic and peri- operative data were reviewed, and the causative organisms of superficial and deep-seated SSI were correlated with intra-operative biliary organisms. Results A total of 202 patients were included. Intraoperative bile sampling was performed in 94 (46.5 %) cases and bactobilia was detected in 62 (65.9 %) cases. Pre-operative biliary drainage was reported in 142 (70.3 %) patients. Intraoperative biliary cultures were resistant to Piperacillin/Tazobactam in 50 % (30) of the samples, and institutional resistance patterns were significantly different (p = 0.006). Similar micro-organisms in bile and surgical site samples were confirmed in 9/25 (36 %) patients with similar antimicrobial resistance patterns. There was no statistically significant association between bactobilia and surgical site infections (p>0.05). Conclusion Our study demonstrated heterogeneity in bile sampling, PBD, and biliary antimicrobial resistance patterns between the different institutions. Intraoperative biliary cultures assist in predicting the microbial species in postoperative SSI, it is therefore important to perform routine intraoperative bile sampling. We recommend that institutes review their internal practices regarding intraoperative bile sampling in patients undergoing PD, as this will allow guidance of antimicrobial selection in patients developing postoperative SSI. Further studies regarding the choice and duration of prophylactic antibiotics for PD are warranted.