Pancreatic cyst fluid harbors a unique microbiome

Abstract

BackgroundIt is clear that specific intestinal bacteria are involved in the development of different premalignant conditions along the gastrointestinal tract. An analysis of the microbial constituents in the context of pancreatic cystic lesions has, however, as yet not been performed. This consideration prompted us to explore whether endoscopically obtained pancreatic cyst fluids (PCF) contain bacterial DNA and to determine the genera of bacteria present in such material.MethodsTotal DNA was isolated from 69 PCF samples. Bacterial 16S rRNA gene-specific PCR was performed followed by Sanger sequencing and de novo deep sequencing for the V3-V4 variable region of 16S rRNA gene.ResultsWe observed that 98.2% of the samples were positive in conventional PCR, and that 100% of selected PCF samples (n = 33) were positive for bacterial microbiota as determined by next generation sequencing (NGS). Comprehensive NGS data analysis of PCF showed the presence of 408 genera of bacteria, of which 17 bacterial genera were uniquely abundant to PCF, when compared to the Human Microbiome Project (HMP) database and 15 bacterial microbiota were uniquely abundant in HMP only. Bacteroides spp., Escherichia/Shigella spp., and Acidaminococcus spp. which were predominant in PCF, while also a substantial Staphylococcus spp. and Fusobacterium spp. component was detected.ConclusionThese results reveal and characterize an apparently specific bacterial ecosystem in pancreatic cyst fluid samples and may reflect the local microbiota in the pancreas. Some taxa with potential deleterious functions are present in the bacterial abundance profiles, suggesting that the unique microbiome in this specific niche may contribute to neoplastic processes in the pancreas. Further studies are needed to explore the intricate relationship between pathophysiological status in the host pancreas and its microbiota.Electronic supplementary materialThe online version of this article (10.1186/s40168-017-0363-6) contains supplementary material, which is available to authorized users.

The Microbiomes of Pancreatic and Duodenum Tissue Overlap and Are Highly Subject Specific but Differ between Pancreatic Cancer and Noncancer Subjects

“…were also extremely high in two RIH subject. In a separate study, 408 genera of bacteria were identified in pancreatic cyst fluids obtained from patients through endoscopy (14); many of the taxa found in pancreatic cysts were similar to those in tissue del Castillo et al…”

“…Other studies have investigated the presence of specific bacterial DNA in the pancreatic tissue of pancreatic cancer subjects, namely species of Helicobacter (11) and Fusobacterium (12). The most comprehensive molecular microbiome studies to date reported the presence of a diverse bacterial populations in fluids collected from the bile duct, pancreas, and jejunum of subjects undergoing pancreaticoduodenectomy (13), and in pancreatic cyst fluid removed endoscopically from pancreatic cysts (14). In mice, bacteria have been shown to translocate from the mouth to the pancreas, and germfree mice have reduced progression of pancreatic ductal adenocarcinoma (15).…”

Association of bacteria in pancreatic fistula fluid with complications after pancreatic surgery

“…In a study of patients with pancreatic cystic lesions that were drained endoscopically, Li et al . also found intestinal bacterial strains, such as Bacteroides spp., E. coli and Shigella spp., to be present in cyst fluid.…”

The Gut Microbiome in Pancreatic Disease

“…6971 Bacteria are also detected in pancreatic cyst fluids including cysts associated with IPMN as well as non-neoplastic cysts, but the significance of these bacteria is not clear. 72 Despite these intriguing studies, the evidence that bacteria within the pancreas contributes to human pancreatic cancer pathogenesis is still limited.…”