Fine-needle aspiration in infected necrotizing pancreatitis in the delayed intervention era: a post hoc analysis of safety, microbiological yield and therapeutic implications

Abstract Objectives Infected necrotizing pancreatitis is preferably managed by postponing invasive interventions and, in selected cases, treatment with antibiotics alone. Consequently, microbial cultures are often lacking, possibly increasing the risk of antibiotic treatment failure and unnecessary use of broad-spectrum antibiotics. The main objective was to describe the culture results of fine-needle aspirations (FNA) in a retrospective cohort of necrotizing pancreatitis patients, and relate this to the administered empirical antibiotic regimen to explore FNA’s potential clinical value. Methods Post hoc analysis of a cohort of 618 patients hospitalized with acute necrotizing pancreatitis in 17 Dutch hospitals (2010–2020). Results Of 618 acute necrotizing pancreatitis patients, 68 (11%) underwent 71 FNA procedures: 11 (15%) endoscopic and 60 (85%) percutaneous. Three patients underwent repeated FNA procedures. Most FNA samples (75%) were culture-positive, all endoscopic FNA were polymicrobial (versus 27% in percutaneous FNA) and therefore suspect for contamination. Among 22 patients who received antimicrobial therapy before percutaneous FNA, 4 (18%) grew pathogens not susceptible to the administered antibiotics. Resistance in positive samples to common Dutch empirical regimens was 28% for cephalosporin/metronidazole, 19% for piperacillin-tazobactam and 21% for meropenem. No periprocedural complications occurred. Conclusions This study suggests that diagnostic percutaneous FNA is a safe procedure with no observed complications, that may be useful in guiding antimicrobial therapy in patients with infected necrotizing pancreatitis, especially when delaying or omitting drainage procedures. Prospective studies and clinical trials are needed to confirm this. Percutaneous FNA is preferred over endoscopic FNA, as the latter carries a high risk of sample contamination.