Biliary Microbiome Research Articles

HPB O01 - Colonization of bile with gammaproteobacteria reduces survival after surgery for pancreatic cancer in patients receiving gemcitabine-based adjuvant chemotherapy

Abstract Background Evidence suggests that the biliary microbiome influences the progression of pancreatic ductal adenocarcinoma (PDAC) in patients undergoing adjuvant chemotherapy. Specifically, Gammaproteobacteria (GPB) has been shown to have the potential to develop mutations which can metabolise gemcitabine into an inactive form. This study hypothesised that GPB influences survival in patients with PDAC undergoing adjuvant gemcitabine-based chemotherapy following surgery. Method This was a retrospective study of patients undergoing pancreatoduodenectomy from 2010 to 2020. Associations between patient and tumour characteristics, survival data, and results of intraoperative bile cultures (GPB+ or GPB-) were investigated. Analysis of patients matched by chemotherapy regimen and numbers of cycles of adjuvant therapy was also performed. Survival was analysed using Kaplan–Meier curves and Cox regression analysis. Results Analysis of 359 patients revealed that adjuvant gemcitabine-based therapy improved overall survival (OS). Patients who receive gemcitabine-based chemotherapy with a GPB+ biliary culture had a shorter OS compared to those who were GPB-, and a median survival of 17.9 vs 26.1 months, P=0.006. After matching for key chemotherapy variables, survival was greater in the GPB- group 26.8 vs 19.8, P=0.016. This association was not seen among patients who received no adjuvant therapy or non-gemcitabine based therapy. Conclusion Patients receiving gemcitabine-based chemotherapy after surgery are likely to have reduction in OS if they have a biliary culture positive for GPB.

HPB SO02 - Cutting surgical site infection rates in perihilar cholangiocarcinoma with informed changes to perioperative antibiotic prophylaxis: A quality improvement project in a UK hepatopancreatobiliary tertiary centre

Abstract Background Perihilar cholangiocarcinoma (pCCA) is the most common cancer of biliary epithelia. While potentially curative, surgical resection is associated with high morbidity and mortality. Surgical site infections (SSIs) are common and pernicious. Preoperative biliary instrumentation is universal: to confirm histological diagnosis and deploy stents to relieve jaundice. Patients receive multiple antibiotic courses as periprocedural prophylaxis and to treat cholangitis. They are at high risk of harbouring bacteria not quelled by perioperative prophylactic antibiotics given for other general surgical procedures. Studying the biliary microbiome, this quality improvement project sought to reduce SSIs through informed changes to local guidelines on perioperative antibiotic prophylaxis. Method Health records of all patients undergoing resection for pCCA in a UK hepatopancreatobiliary centre from February 2009 to January 2024 were analysed retrospectively (n=118). For all patients, we routinely sent intraoperative bile swabs for culture and sensitivity. Informed by these microbiology results, multidisciplinary discussion led to changes to local guidelines in March 2019. Formerly, cefuroxime and metronidazole were given on anaesthetic induction, with subsequent antibiotic choice and duration according to surgeon preference. New guidance stipulated teicoplanin and piperacillin/tazobactam be given on induction and for 72 hours postoperatively. We studied the impact of these changes on SSIs within 30 days. Results 75 patients received cefuroxime and metronidazole; 43 patients were given teicoplanin and piperacillin/tazobactam after the policy change. Proportions of patients who developed any SSI substantially fell following the guideline change (55% v 28%; p=0.0049), primarily owing to reductions in intraperitoneal collections (39% v 21%; p=0.047). Rates of deep (8% v 2%; p=0.21) and superficial incisional infections (8% v 5%; p=0.49) were not significantly affected. Associated secondary outcomes were drops in post-hepatectomy liver failure (17% v 5%; p=0.047), and 90-day mortality (16% v 5%; p=0.067), albeit the latter was not statistically significant. Conclusion Invasive investigative work-up, disease complications and exposure to multiple courses of antibiotics prior to resection of pCCA subject patients’ biliary systems to colonisation with antimicrobial-resistant bacteria. We urge centres that undertake these operations to introduce intraoperative bile cultures as a part of routine practice to inform local guidance on perioperative antimicrobial prophylaxis. We demonstrated effective antibiotics in the perioperative period can have enormous benefits to patient outcomes.

Cultured Bacteria Isolated from Primary Sclerosing Cholangitis Patient Bile Induce Inflammation and Cell Death.

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by inflammation and progressive fibrosis of the biliary tree. The pathogenesis of PSC remains poorly understood, and there are no effective therapeutic options. Previous studies have observed associations between changes in the colonic and biliary microbiome and PSC. We aimed to determine whether bacterial isolates cultured from PSC patient bile induced disease-associated phenotypes in cells. Bile was collected from PSC patients (n=10) by endoscopic retrograde cholangiography and from non-PSC controls (n=3) undergoing cholecystectomies. Biliary bacteria were cultured anaerobically, and 50 colonies per sample were identified by 16S rRNA sequencing. The effects of supernatants from seven PSC-associated bacterial strains on cellular phenotypes were characterized using human colonic (Caco-2), hepatic (HepG2), and biliary (EGI-1) cells. No bacteria were isolated from non-PSC controls, while bacteria were cultured from most PSC patients. The PSC bile microbiomes exhibited reduced diversity compared to the gut or oral cavity, with one or two bacterial strains predominating. Overall, PSC-associated bacteria produced factors that were cytotoxic to hepatic and biliary cells. Enterococcus faecalis , and to a lesser extent Veillonella parvula , induced epithelial permeability, while Escherichia coli, Fusobacterium necrophorum , and Klebsiella pneumoniae induced inflammatory cytokines in biliary cells. Our data suggest that bacteria cultured from PSC bile induce cellular changes that may contribute to PSC disease pathogenesis. Enterococcus may promote intestinal permeability, facilitating bacterial migration to the biliary tree. Once there, Escherichia, Fusobacterium and Klebsiella , may cause inflammation and damage in biliary and liver cells.

Postoperative prophylactic antibiotic therapy after pancreaticoduodenectomy in bile duct-stented patients reduces postoperative major complications

BackgroundPancreaticoduodenectomy can entail a high complication rate, especially in patients who underwent preoperative bile duct drainage through bile duct stenting. Pancreaticoduodenectomy bile duct stenting patients frequently receive prophylactic antibiotic therapy in the postoperative period. However, the exact value and the benefit of prophylactic antibiotic therapy in pancreaticoduodenectomy bile duct stenting patients remains under-investigated and thus unclear. MethodWe conducted a retrospective single-center study of pancreaticoduodenectomy bile duct stenting patients between January 2007 and December 2022. Demographic, clinical, laboratory, and pathology data of 370 patients were collected, and intraoperative swab cultures of the bile were obtained from all patients upon transection of the common bile duct. The groups to be investigated were formed on the basis of postoperative antibiotic prophylaxis. Postoperative complications and antibiotic resistance analysis were recorded. ResultsPostoperative antibiotic prophylaxis in stented patients after pancreaticoduodenectomy significantly reduced major complications (odds ratio: 0.547 [95% confidence interval 0.327–0.915]; P = .02) such as reoperation (P = .041) and readmission to the intensive care unit (P = .037). Patients with Enterococcus faecalis (odds ratio: 1.699 [95% confidence interval 0.978–2.950];P = .048), Enterococcus faecium (odds ratio: 1.808 [95% confidence interval 1.001–3.264]; P = .050), or Citrobacter (odds ratio: 2.211 [95% confidence interval 1.087–4.497]; P = .029) in their bile had a higher probability of developing wound infections. Appropriate antibiotic prophylaxis, according to the bile duct microbiome, significantly reduced the risk of wound infection (odds ratio: 2.239 [95% confidence interval 1.167–4.298]; P = .015). ConclusionPostoperative antibiotic prophylaxis in pancreaticoduodenectomy bile duct stenting patients significantly reduced major complications such as intensive care stay and reoperation. Targeted antibiotic treatment according to the biliary microbiome reduced the incidence of wound infections.

Profiles of biliary microbiota in biliary obstruction patients with Clonorchis sinensis infection.

Clonorchis sinensis (C. sinensis) is a epidemiologically significant food-borne parasite, causing several hepatobiliary diseases. Biliary microbiota community structure might be influenced by infection with pathogens. However, the biliary microbiome of biliary obstruction patients infected with C. sinensis is still an unexplored aspect. A total of 50 biliary obstruction patients were enrolled, including 24 infected with C. sinensis and 26 non-infected subjects. The bile samples were collected by Endoscopic Retrograde Cholangiopancretography. Biliary microbiota alteration was analyzed through high-throughput 16S ribosomal RNA (rRNA) gene sequencing. Our findings revealed that there was significant increase in both richness and diversity, as well as changes in the taxonomic composition of the biliary microbiota of C. sinensis infected patients. At the phylum level, C. sinensis infection induced Proteobacteria increased and Firmicutes reduced. At the genus level, the relative abundance of Pseudomonas and Staphylococcus increased significantly, while Enterococcus decreased prominently in infected groups (P < 0.05). The PICRUSt analysis further showed remarkably different metabolic pathways between the two groups. C. sinensis infection could modify the biliary microbiota, increasing the abundance and changing the phylogenetic composition of bacterial in biliary obstruction patients. This study may help deepen the understanding of the host-biliary microbiota interplay with C. sinensis infection on the background of biliary obstruction and provide new insights into understanding the pathogenesis of clonorchiasis.

Neoadjuvant therapy does not impact the biliary microbiome in patients with pancreatic cancer.

Pancreatic adenocarcinoma (PDAC) often impinges on the biliary tree and obstruction necessitates stent placement increasing the risk of surgical site infections (SSIs). We sought to explore the impact of neoadjuvant therapy on the biliary microbiome and SSI risk in patients undergoing resection. A retrospective analysis was performed on 346 patients with PDAC who underwent resection at our institution from 2008 to 2021. Univariate and multivariate methods were utilized for analysis. Biliary stenting rates were similar between groups but resulted in increased bile culture positivity (97% vs. 15%, p < 0.001). Culture positivity did not differ between upfront resection or neoadjuvant chemotherapy (NAC) (77% vs. 80%, p = 0.60). NAC-alone versus neoadjuvant chemoradiotherapy did not impact biliary positivity (80% vs. 79%, p = 0.91), nor did 5-fluorouracil versus gemcitabine-based regimens (73% vs. 85%, p = 0.19). While biliary stenting increased incisional SSI risk (odds ratios[OR]: 3.87, p = 0.001), NAC did not (OR: 0.83, p = 0.54). Upfront resection, NAC, and chemoradiotherapy were not associated with biliary organism-specific changes or antibiotic resistance patterns. Biliary stenting is the greatest predictor for positive biliary cultures and SSIs in resected PDAC patients. Neither NAC nor radiotherapy impact bile culture positivity, speciation, rates, or antibiotic resistance patterns, and perioperative antibiotic prophylaxis should not differ.

Bile Composition - which Components Can Have Clinical Significance? A Review of the Literature

Over the years, scientific research concerning the qualitative analysis of bile and its use in diagnostics and treatment, have been very limited. Due to unsatisfactory results of detection, inter alia, cholangiocarcinoma or gallbladder carcinoma, and the necessity to discover more efficient techniques of diagnostics, bile has become an interesting direction to study. Nowadays, thanks to the latest research, analysis of concentration i.e. specific bile salts, proteins, nucleic or fatty acids in bile or imbalance of biliary microbiome, could play a crucial role in cancer detection or prognosis of progression such diseases as primary sclerosing cholangitis/ choledocholithiasis. This review article provides an overview of individual biliary solutes, which may play a role in diagnostics improvement.

Long term assessment of antibiotic prophylaxis and biliary microbiome in pancreaticoduodenectomy.

Surgical site infections (SSI) can represent a major complication of pancreaticoduodenectomy (PD). We summarize the outcomes of process improvement efforts to reduce the SSI rates in PD that includes replacing Cefazolin with Ceftriaxone-Metronidazole as antibiotic prophylaxis. Additional efforts included current assessment of biliary microbiome and potential prophylactic failures based on bile cultures and suspected antibiotic allergies. A single-center review of PD patients from January-2012 to March-2021. Study groups were divided into Pre and Post May-2015 (Group 1 and 2, respectively) when Ceftriaxone-Metronidazole prophylaxis and routine intraoperative cultures were standardized. Univariate and multivariable analyses were conducted to assess groups' differences and association with SSI. Six hundred ninety patients identified [267(38.7%) and 423(61.3%) in Group 1 and Group2, respectively]. After antibiotic change, SSI rates decreased from 28.1% to 16.5% (incisional: 17.6%-7.5%, organ-space or abscess: 17.2%-13.0%), Group 1 and Group 2, respectively, P<0.001. Ceftriaxone-Metronidazole was used in 75.9% of patients Group 2. When adjusting for other covariates, an SSI-decrease was associated only with Ceftriaxone-Metronidazole (OR 0.34, P<0.001). Ongoing process improvement has resulted in decreased SSIs with Ceftriaxone-Metronidazole prophylaxis. The benefit of Ceftriaxone-Metronidazole is independent of the biliary microbiome. Improving prophylaxis for those with suspected penicillin allergy is warranted.

Metagenomic Sequencing of the Gallbladder Microbiome: Bacterial Diversity Does Not Vary by Surgical Pathology

IntroductionAlterations in the microbiome contribute to the pathogenesis of many gastrointestinal diseases. However, the composition of the microbiome in gallbladder disease is not well described. MethodsWe aimed to characterize the biliary microbiome in cholecystectomy patients. Bile and biliary stones were collected at cholecystectomy for a variety of surgical indications between 2017 and 2019. DNA was extracted and metagenomic sequencing was performed with subsequent taxonomic classification using Kraken2. The fraction of bacterial to total DNA reads, relative abundance of bacterial species, and overall species diversity were compared between pathologies and demographics. ResultsA total of 74 samples were obtained from 49 patients: 46 bile and 28 stones, with matched pairs from 25 patients. The mean age was 48 years, 76% were female, 29% were Hispanic, and 29% of patients had acute cholecystitis. The most abundant species were Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pasteurianus. The bacterial fraction in bile and stone samples was higher in acute cholecystitis compared to other non-infectious pathologies (p < 0.05). Neither the diversity nor differential prevalence of specific bacterial species varied significantly between infectious and other non-infectious gallbladder pathologies. Multivariate analysis of the non-infectious group revealed that patients over 40 years of age had increased bacterial fractions (p < 0.05). ConclusionsMetagenomic sequencing permits characterization of the gallbladder microbiome in cholecystectomy patients. Although a higher prevalence of bacteria was seen in acute cholecystitis, species and diversity were similar regardless of surgical indication. Additional study is required to determine how the microbiome can contribute to the development of symptomatic gallbladder disease.

Microbiota analysis with next-generation 16S rDNA gene sequencing in recurrent common bile duct stones.

BackgroundEndoscopic retrograde cholangiopancreatography (ERCP) is the main remedy for gallstones, but the postoperative recurrence rate is high. Recent research has indicated that the biliary microbiome takes part in the pathogenesis of cholelithiasis. However, it is not yet known whether biliary microbiome dysbiosis is relevant to recurrent cholelithiasis.MethodsThus, we investigated the bacterial communities of the biliary microbiomes of patients with recurrent common bile duct (CBD) stones and analyzed the relationship between recurrent CBD stones and biliary microbiota. The bile specimens of 5 patients with recurrent CBD stones (FF) and 45 patients with primary CBD stones (YF) were collected during the ERCP process. The microbiota was analyzed using 16S ribosomal DNA (rDNA) high-throughput sequencing. We also identified the link between recurrent CBD stones and biliary microbiota.ResultsOur results showed that at the phylum level, proteobacteria and firmicutes were the main two genera groups, and proteobacteria was high in FF patients. Additionally, synergistetes were high, but Bacteroidetes and actinobacteria were low in FF patients. The microbiomes in the bile of the YF patients were more evenly distributed than those in the bile of the FF patients. We also discovered that FF patients had decreased microbial bile diversity. At the genus level, klebsiella dominated in the FF patients, while Escherichia-shigella dominated in the YF patients. Additionally, klebsiella was higher in the FF patients than the YF patients.ConclusionsThe observed differences in the genera between the recurrent CBD stone FF patients and the YF patients provide novel insights into the link between biliary microbiota changes and recurrent CBD stones.

Patients with Primary and Secondary Bile Duct Stones Harbor Distinct Biliary Microbial Composition and Metabolic Potential

IntroductionCholelithiasis has a high incidence worldwide and limited treatment options due to its poorly understood pathogenesis. Furthermore, the role of biliary microbiota in cholelithiasis remains understudied. To address these questions, we performed microbial sequencing from biliary samples from primary bile duct stone (PBDS) and secondary bile duct stone (SBDS) patients.ResultsWe analyzed in total 45 biliary samples, including those from cholelithiasis patients with PBDS or SBDS and people with other digestive diseases. 16S rRNA sequencing showed the bacteria family Alcaligenaceae increased in relative abundance in the lithiasis group compared with the non-lithiasis group. In addition, the PBDS group showed significantly lower bacterial diversity than SBDS, with Propionibacteriaceae, Sphingomonadaceae, and Lactobacillaceae as the most significant bacteria families decreased in relative abundance. We further performed whole metagenomic shotgun sequencing (wMGS) and found increased ability of biofilm synthesis and the ability to sense external stimuli in PBDS based on functional annotation of mapped reads. From genome-resolved analysis of the samples, we identified 36 high-quality draft bacterial genome sequences with completion ≥70% and contamination ≤10%. Most of these genomes were classified into Proteobacteria, Firmicutes, or Actinobacteria.ConclusionsOur findings indicated that there is a subtle impact on biliary microbiome from cholelithiasis while the difference is more pronounced between the PBDS and SBDS. It was revealed that the diversity of biliary microbiota in PBDS is lower, while some metabolic pathways are up-regulated, including those linked to higher incidence of different types of cancer, providing new insights for the understanding of cholelithiasis with different origin.

Potential Role of Inflammation-Promoting Biliary Microbiome in Primary Sclerosing Cholangitis and Cholangiocarcinoma.

Simple SummaryThis is the first study to investigate both bile and stool microbiota profiles in PSC and CCA, mostly perihilar CCA. Samples with less than 2000 reads were excluded from the compositional analysis to reduce false associations. We adjusted for demographic and clinical factors influencing the biliary and stool microbiota in PSC and CCA patients. Bile and stool have different profiles of microbiota, although the bile and stool microbiome from the same subject showed more similarity than those from different subjects. Increased species richness and abundance of Fusobacteria in bile was correlated with the duration of PSC and characterized the bile of CCA patients. The unique microbial signature in the bile of patients with CCA raises the possibility of a role for microbiota-driven inflammation in the pathogenesis of perihilar CCA.Background: Primary sclerosing cholangitis (PSC) is a major risk factor for cholangiocarcinoma (CCA). We investigated biliary and fecal microbiota to determine whether specific microbes in the bile or stool are associated with PSC or CCA. Methods: Bile was obtained from 32 patients with PSC, 23 with CCA with PSC, 26 with CCA without PSC, and 17 controls. Over 90% of bile samples were from patients with perihilar CCA. Stool was obtained from 31 patients with PSC (11 were matched to bile), 16 with CCA with PSC (10 matched to bile), and 11 with CCA without PSC (6 matched to bile). Microbiota composition was assessed using 16SrRNA-marker-based sequencing and was compared between groups. Results: Bile has a unique microbiota distinguished from negative DNA controls and stool. Increased species richness and abundance of Fusobacteria correlated with duration of PSC and characterized the biliary microbiota in CCA. Stool microbiota composition showed no significant differences between groups. Conclusions: We identified a unique microbial signature in the bile of patients with increased duration of PSC or with CCA, suggesting a role for microbiota-driven inflammation in the pathogenesis and or progression to perihilar CCA. Further studies are needed to test this hypothesis.

Microbiologic risk factors of recurrent choledocholithiasis post-endoscopic sphincterotomy.

BACKGROUNDCholedocholithiasis is a severe disorder that affects a significant portion of the world’s population. Treatment using endoscopic sphincterotomy (EST) has become widespread; however, recurrence post-EST is relatively common. The bile microbiome has a profound influence on the recurrence of choledocholithiasis in patients after EST; however, the key pathogens and their functions in the biliary tract remain unclear. AIMTo investigate the biliary microbial characteristics of patients with recurrent choledocholithiasis post-EST, using next-generation sequencing.METHODSThis cohort study included 43 patients, who presented with choledocholithiasis at the Guangdong Second Provincial General Hospital between May and June 2020. The patients had undergone EST or endoscopic papillary balloon dilation and were followed up for over a year. They were divided into either the stable or recurrent groups. We collected bile samples and extracted microbial DNA for analysis through next-generation sequencing. Resulting sequences were analyzed for core microbiome and statistical differences between the diagnosis groups; they were examined using the Kyoto Encyclopedia of Genes and Genomes pathway hierarchy level using analysis of variance. Correlation between the key genera and metabolic pathways in bile, were analyzed using Pearson’s correlation test. RESULTSThe results revealed distinct clustering of biliary microbiota in recurrent choledocholithiasis. Higher relative abundances (RAs) of Fusobacterium and Neisseria (56.61% ± 14.81% vs 3.47% ± 1.10%, 8.95% ± 3.42% vs 0.69% ± 0.32%, respectively) and the absence of Lactobacillus were observed in the bile of patients with recurrent disease, compared to that in stable patients. Construction of a microbiological co-occurrence network revealed a mutual relationship among Fusobacterium, Neisseria, and Leptotrichia, and an antagonistic relationship among Lactobacillales, Fusobacteriales, and Clostridiales. Functional prediction of biliary microbiome revealed that the loss of transcription and metabolic abilities may lead to recurrent choledocholithiasis. Furthermore, the prediction model based on the RA of Lactobacillales in the bile was effective in identifying the risk of recurrent choledocholithiasis (P = 0.03).CONCLUSIONWe demonstrated differences in the bile microbiome of patients with recurrent choledocholithiasis compared to that in patients with stable disease, thereby adding to the current knowledge on its microbiologic etiology.

The biliary microbiome in ischaemic-type biliary lesions can be shaped by stenting but is resilient to antibiotic treatment.

This study aims to characterize the biliary microbiome as neglected factor in patients with ischaemic-type biliary lesions (ITBL) after liver transplantation. Therefore, the V1-V2 region of the 16S rRNA gene was sequenced in 175 bile samples. Samples from patients with anastomotic strictures (AS) served as controls. Multivariate analysis and in silico metagenomics were applied cross-sectionally and longitudinally. The microbial community differed significantly between ITBL and AS in terms of alpha and beta diversity. Both, antibiotic treatment and stenting were associated independently with differences in the microbial community structure. In contrast to AS, in ITBL stenting was associated with pronounced differences in the biliary microbiome, whereas no differences associated with antibiotic treatment could be observed in ITBL contrasting the pronounced differences found in AS. Bacterial pathways involved in the production of antibacterial metabolites were increased in ITBL with antibiotic treatment. After liver transplantation, the biliary tract harbours a complex microbial community with significant differences between ITBL and AS. Fundamental changes in the microbial community in ITBL can be achieved with biliary stenting. However, the effect of antibiotic treatment in ITBL was minimal. Therefore, antibiotics should be administered wisely in order to reduce emerging resistance of the biliary microbiome towards external antibiotics.

The association between bacterobilia and the risk of postoperative complications following pancreaticoduodenectomy.

Pre-operative biliary bacterial colonisation (bacterobilia) is considered a risk factor for infectious complications after pancreaticoduodenectomy (PD). This study aimed to investigate the role of the PD biliary microbiome grown in the development of post-PD complications. In a retrospective study of 162 consecutive patients undergoing PD (2008-2018), intra-operative bile cultures were analyzed and sensitivities compared to pre-anesthetic antibiotics and thirty-day post-surgery complications. Bacterobilia was present in 136 patients (84%). Most bile cultures grew bacteria resistant to pre-operative antibiotics (n=112, 82%). Patients with bacterobilia had significantly higher rates of major complication than patients without (P=0.017), as well as higher rates of surgical-site infections (SSI) (P=0.010). Patients with negative bile cultures (n=26) had significantly lower rates of major complication and SSI than those growing sensitive (n=24) or non-sensitive (n=112) bacteria (major complication P=0.029 and SSI P=0.011). Positive bile cultures were associated with a higher incidence of major complications and SSI. Patients with sterile bile cultures had the lowest risk of post-operative complications and efforts to reduce rates of bacterobilia, such as limitation of biliary instrumentation, should be considered. Sensitivity to antibiotics had no effect upon the rate of post-operative complications, but this may reflect low cohort numbers.

Long Term Assessment of Antibiotic Prophylaxis and Biliary Microbiome in Pancreaticoduodenectomy

Introduction: Surgical site infections (SSI) represent a potential major complication of pancreaticoduodenectomy. Quality improvement efforts should be directed at assessing SSI rates, surgical technique, and antibiotic prophylaxis. In addition, we added assessment of the biliary-microbiome as a mechanism to guide prophylaxis and therapy for SSI. This study aimed to analyze our SSI rates based on changes to our prophylaxis protocol and relationship to biliary-microbiome. Method: A Single-center-retrospective analysis was conducted for pancreaticoduodenectomy patients from January-2012 to March-2021. Study groups were divided into Pre and Post May-2015 when Ceftriaxone-Metronidazole prophylaxis and routine intraoperative cultures were standardized. Relevant variables were analyzed in univariate and multivariable logistic regression to demonstrate the association with developing SSI. Results: Six hundred ninety patients received antibiotic prophylaxis [267(38.7%) and 423(61.3%) in Pre and Post-May-2015 periods, respectively]. Ceftriaxone-Metronidazole use was 75.9% Post May-2015, which associated with SSI-decrease from 28.1%-16.5% (incisional: 17.6%-7.5%, organ-space or abscess: 17.2%-13.0%), Pre and Post periods, respectively, P<0.001. The multivariable analysis showed that SSI-decrease was associated only with Ceftriaxone-Metronidazole (OR 0.36, P<0.001). Post May-2015, SSIs in those not receiving Ceftriaxone-Metronidazole (Ciprofloxacin was the dominant alternative) were 28.7% vs. 12.6%, P<0.001. Intraoperative cultures were collected from 356(51.6%) patients, and SSI cultures were available from 69(47.6%) SSIs, Table 1. However, only 56% of positive SSI cultures were similar to those isolated intraoperatively. Conclusions: Ongoing process improvement has resulted in decreased SSIs with Ceftriaxone-Metronidazole prophylaxis. The benefit of Ceftriaxone-Metronidazole is independent of the biliary microbiome. Improving prophylaxis for those intolerant to Ceftriaxone-Metronidazole is warranted.Tabled 1FP14-3Table 1.Culture ResultsCeftriaxone-MetronidazoleOther ProphylaxisIntraoperative Cultures(n=253)SSI Cultures(n=13)Intraoperative Cultures(n=103)SSI Cultures(n=56)Negative culture92 (36.36%)1 (7.69%)41 (39.81%)9 (16.07%)Staphylococcus Species10 (3.95%)2 (15.38%)9 (8.74%)13 (23.21%)Enterococcus Species58 (22.92%)6 (46.15%)14 (13.59%)11 (19.64%)Pseudomonas aeruginosa9 (3.56 %)3 (23.08%)10 (9.71%)10 (17.86 %)Streptococcus Species38 (15.02%)018 (17.48%)10 (17.86%)Klebsiella Species31 (12.25%)1 (7.69%)14 (13.59%)11 (19.64 %)Escherichia coli18 (7.11%)2 (15.38%)5 (4.85%)7 (12.5%)Candida Species69 (27.27%)3 (23.08%)18 (17.48%)6 (10.71%) Open table in a new tab

Intraoperative Bile Culture in Pancreaticoduodenectomy: Teaching Old Dogma New Tricks

IntroductionBiliary stents increase surgical site infections (SSIs) following pancreaticoduodenectomy due to bactibilia and contaminated intraoperative bile spillage. Intraoperative bile culture (IOBC) is performed to guide empiric therapy for SSIs; however, its utility is poorly studied. We sought to evaluate IOBC and the interplay between stenting, bactibilia, and SSI following pancreaticoduodenectomy. MethodsPatients undergoing pancreaticoduodenectomy from January 2008 to April 2020 were identified through our institutional National Surgical Quality Improvement Project (NSQIP) database; patients without IOBC were excluded. Odds of SSI were analyzed with multivariable logistic regression. ResultsFour-hundred-eighty-three patients were identified. One-hundred-eighty-nine (39%) patients had plastic stents and 154 (32%) had metal stents. Three-hundred-twenty-nine (96%) patients with stents had bactibilia versus 18 (13%) without stents (P < 0.001). The biliary microbiome and antibiotic resistance patterns in patients with metal and plastic stents were nearly identical. Of 159 NSQIP-defined SSIs, most were incisional (n = 92, 58%). Bactibilia and stent presence were associated with incisional (OR 3.69 and 3.39, both P < 0.001) but not organ space SSI (P > 0.1); however, stent type was not (P > 0.5). Of the 73 speciated SSI cultures, an IOBC-identified organism was present in 42 (58%), while at least one organism not found in the IOBC was present in 49 (67%). ConclusionBactibilia is associated with incisional but not organ space SSI following pancreaticoduodenectomy and is strongly associated with stent presence. Stent type does not independently influence the biliary microbiome or SSI risk. IOBC has a poor ability to predict causative organisms in SSIs following pancreaticoduodenectomy and is not recommended for routine use.

Biliary Tract Instrumentations Prior to Elective Cholecystectomy: Effect on Biliary Microbiome.

Background: Calculus biliary disease is a common condition that requires invasive procedures in complicated cases. The effect of biliary instrumentation on the biliary microbiome and its impact on surgical complications after elective cholecystectomy remains unclear. This study aimed to assess the impact of prior biliary instrumentation on the biliary microbiome, as well as on the clinical outcomes of cholecystectomy. Patients and Methods: This retrospective study included all patients who underwent elective cholecystectomy for calculus biliary disease between 2015 and 2020 in a single medical center. Data regarding biliary instrumentation prior to cholecystectomy, biliary cultures obtained during cholecystectomy, and clinical outcomes were collected. A comparison between patients with and without prior instrumentation was performed with regard to biliary cultures and clinical outcomes. Results: Of the 508 patients studied, 109 patients underwent biliary instrumentation prior to cholecystectomy. Patients with prior instrumentation were older and more likely to be men (p < 0.0001). Prior instrumentation was also associated with higher rates of conversion to open surgery (p < 0.0001). Positive biliary cultures and polymicrobial growth were both more common among patients with prior instrumentation (p < 0.0001). Prior instrumentation was associated with longer length of hospital stay, as well as higher rates of perioperative complications and surgical site infection (p < 0.0001). Conclusions: Prior instrumentation was associated with poorer clinical outcomes and affected the biliary microbiome. The different results of biliary cultures in these patients may suggest that an alternative empiric antibiotic regimen should be considered when treating patients with biliary instrumentation.

Microbiomic profiles of bile in patients with benign and malignant pancreaticobiliary disease.

417 Background: In pancreaticobiliary (PB) cancers, there is a paucity of data on predictive and pathophysiologic role of the biliary microbiome. We analyzed bile collected from patients with benign and malignant PB diseases to identify microbiomic signatures associated with malignancy. Methods: We collected bile samples from consenting patients during routine endoscopic retrograde cholangiopancreatography at the Cleveland Clinic, approved by the Institutional Review Board. DNA was extracted from bile specimens using PowerViral RNA/DNA Isolation kit. Bacterial 16S rRNA gene amplification and library construction were performed according to the 16S Metagenomic Sequencing Library Preparation guide from Illumina. Post-sequencing analysis was done using QIIME (Quantitative Insights Into Microbial Ecology), Bioconductor phyloseq, microbiomeSeq and mixMC packages. Results: Of 46 enrolled patients, 32 had PB cancers including pancreatic (N = 25), cholangiocarcinoma (N = 6), and gallbladder (N = 1). The rest (N = 14) had benign PB diseases including acute and chronic pancreatitis, and gallstones. Using multivariate approach in mixMC to classify Operational Taxonomic Units (OTUs), we found a predominance of genera Dicekeya (p = 0.0002), [ Eubacterium] hallii group (p = 0.0007) , Bacteroides (p = 0.00099) , Faecalibacterium (p = 0.007) , Facklamia (p = 0.013) , Peptococcus (p = 0.013) , Bergeyella (p = 0.0024) , Lachnospira (p = 0.026) , and Lactobacillus (p = 0.025) in bile samples from PB cancers as compared to benign PB diseases. Furthermore, bile samples from patients with pancreatic cancer showed an increased abundance of genera Enterobacter, Parabacteroides, Atopobium, Alloprevotella, Prevotella 7, Acinetobacter, Bergeyella, Clostridium sensu stricto, Lactobacillus, and Rothia; and a decreased abundance of genera Tannerella, Peptococcus, Colinsella, Capnocytophaga, Achromobacter, Ruminococcus 2, Bacteroides, Alistipes, Barnesiella,, Lachnoclostridium, Lautropia, Akkermansia, and Christensenellaceae R-7 group as compared to bile samples from patients with cholangiocarcinoma. Conclusions: Distinct microbiome signatures are associated with benign and malignant PB diseases. There is a difference in the relative abundance of OTUs in bile samples between patients with benign PB diseases vs PB cancers, and between pancreatic cancer vs cholangiocarcinoma. Our findings raise the possibility that either these OTUs have a role in carcinogenesis, or that changes in the microenvironment of benign PB diseases differ from PB cancers leading to distinct separation of the OTU clusters. Further studies to explore and validate our findings are needed.

Bile Microbiota in Patients with Pigment Common Bile Duct Stones

BackgroundCommon bile duct (CBD) stone is one of the most prevalent gastroenterological diseases, but the role played by biliary microbiota in the pathogenesis of CBD stones remains obscure. The aim of this study was to investigate the characteristics of the biliary tract core microbiome and its potential association with the formation of pigment stones.MethodsTwenty-eight patients with biliary obstruction of various causes were enrolled. Thirteen had new-onset pigment CBD stone. Of the remaining 15, four had benign biliary stricture, four had gallbladder cancer, three had pancreatic cancer, 3 had distal CBD cancer, and one had hepatocellular carcinoma. Endoscopic retrograde cholangiopancreatography was used to collect bile samples for DNA extraction, 16S ribosomal RNA gene sequencing, and bile microbiota composition analysis.ResultsProteobacteria (61.7%), Firmicutes (25.1%), Bacteroidetes (5%), Fusobacteria (4.6%), and Actinobacteria (2.6%) were the most dominant phyla in the bile of the 28 study subjects. A comparison between new-onset choledocholithiasis and other causes of biliary obstruction (controls) showed Enterococcus was found to be significantly abundant in the CBD stone group at the genus level (linear discriminant analysis score = 4.38; P = 0.03). However, no other significant compositional difference was observed.ConclusionThis study demonstrates an abundance of microbiota in bile juice and presents a biliary microbiome composition similar to that of duodenum. The study also shows Enterococcus was significantly abundant in the bile juice of patients with a brown pigment stone than in controls, which suggests Enterococcus may play an important role in the development of pigment stones.