# Antibiotic Resistance Patterns in Pancreatic Surgery: A Tailor-Made Antibiotic Prophylaxis in a Secondary Hospital

## TL;DR

This study finds that patients who had prior bile drainage before pancreatic surgery had more bacterial growth in their bile, and these bacteria were often resistant to standard antibiotics.

## Contribution

The study identifies local antibiotic resistance patterns in bile cultures from patients with prior biliary drainage, suggesting current prophylaxis is inadequate.

## Key findings

- Patients with prior biliary drainage had 90.9% positive bile cultures, compared to others.
- Most isolates showed resistance to cefuroxime, a commonly used surgical antibiotic.
- Despite higher bacterial growth, prior drainage did not significantly increase the risk of pancreatic fistulas.

## Abstract

Background/objectives: The pancreatoduodenectomy is a high-risk surgery, and its high morbidity rate is mostly related to postoperative infectious complications. Positive bile cultures are associated with both increased frequency and severity of pancreatic fistulas; this is more common in previously drained or infected bile ducts. The currently used antibiotic regimens for surgical prophylaxis appear insufficient to cover the microorganisms identified in bile cultures of patients previously submitted to biliary drainage. This study aims primarily to compare the rates of positive bile cultures and antibiotic resistance between patients with and without preoperative biliary drainage.​ And, as a secondary aim, to evaluate whether these positive cultures are associated with an increased risk of postoperative pancreatic fistulas (POPF).

Methods: We conducted a retrospective single-center study of patients undergoing pancreatoduodenectomy to compare intraoperative bile samples from patients with prior bile drainage with those without prior bile drainage between 2015 and 2022. The main aim was to compare the percentage of positive bile cultures, as well as describe the microbiological patterns and the respective antibiotic susceptibility. The secondary aim was to compare postoperative complications, such as pancreatic fistula.

Results: During the study period, 69 patients underwent pancreatoduodenectomy, and 36 patients met the inclusion criteria. Of the 36 patients, 22 had been previously submitted to bile drainage, and 14 went straight to surgery. The mean age of the patients was 72.7 years, with 22 (61.1%) patients being male. The leading surgical indication was pancreatic adenocarcinoma. The presence of positive bile cultures was significantly higher in patients with previously performed bile drainage, with 20 (90.9%) having positive cultures; 16 (80%) of these patients presented with polymicrobial growth. Notably, Klebsiella pneumoniae and Enterococcus faecium were the most frequently isolated Gram-negative and Gram-positive bacteria, respectively. A significant proportion of bacteria exhibited resistance to the common surgical prophylaxis, with 17 (85%) of the instrumented group resistant to cefuroxime. Complications included an 11 (50%) rate of POPF in the drainage group and a 3 (21.4%) rate in the no drainage group, with no difference between the two groups.

Conclusions: In conclusion, our study shows that the frequency of positive bile cultures is much higher in patients previously submitted to biliary drainage, although this did not increase the risk of pancreatic fistula. After subgroup analyses, we concluded that the current standard antibiotic prophylaxis at our institution is inadequate to cover the microbiologic profile observed in our local patient cohort.