High risk pathogens and risk factors for postoperative pancreatic fistula after pancreatectomy; a retrospective case-controlled study

Background: Although the rates of surgical site infection are decreasing, surgical site infection after pancreatectomy remains frequent because of postoperative pancreatic fistula. Recent studies suggested a relationship between postoperative pancreatic fistula and pathogens cultured from drainage fluids after pancreatectomy. This study aimed to assess and evaluate high-risk pathogens cultured from postoperative drainage fluids for postoperative pancreatic fistulas or severe postoperative complications after pancreatectomy. Materials and methods: We retrospectively enrolled patients who underwent pancreaticoduodenectomy or distal pancreatectomy between 2012 and 2019. We assessed clinical characteristics and microbiological results of drainage cultures of pancreaticoduodenectomy or distal pancreatectomy patients, and we investigated the risk factors for clinically relevant postoperative pancreatic fistulas and Clavien-Dindo status using univariate and multivariate analyses. Finally, we detected high-risk pathogens from drainage cultures and analyzed the correlation between these pathogens and the severity of clinically relevant postoperative pancreatic fistula or Clavien-Dindo status. Results: Four hundred and twenty-nine patients were enrolled: 257 underwent pancreaticoduodenectomy and 172 underwent distal pancreatectomy. Clinically relevant postoperative pancreatic fistulas and Clavien-Dindo status ≥ III were more frequently seen in pancreaticoduodenectomy patients than in distal pancreatectomy patients, namely grade C postoperative pancreatic fistula, which was observed in 19 pancreaticoduodenectomy patients. The most common pathogen found from drainage cultures was Enterococcus species, followed by Enterobacter species and Candida species. All pathogens were associated with clinically relevant postoperative pancreatic fistulas; however, Candida species was a dominant microorganism of clinically relevant postoperative pancreatic fistulas grade C, Clavien-Dindo status ≥ IV, and hemorrhage due to pseudoaneurysm. Conclusion: The presence of Candida species in the drainage fluid culture after pancreaticoduodenectomy can be a predictive factor of severe infectious complications, including postoperative pancreatic fistulas; thus, we should regularly collect cultures from drainage fluids and monitor for Candida infection.