Listeria monocytogenes 10403S Alternative Sigma-54 Factor σL Has a Negative Role on Survival Ability Under Bile Exposure

Listeria monocytogenes is a Gram-positive bacterium causing listeriosis in animals and humans. To initiate a foodborne infection, L. monocytogenes has to pass through the host gastrointestinal tract (GIT). In this study, we evaluated survival abilities of L. monocytogenes 10403S wild type (WT) and its isogenic mutants in alternative sigma (σ) factor genes (i.e., sigB, sigC, sigH, and sigL) under simulated gastric, duodenal, and bile fluids. Within 10min of exposures, only bile fluid was able to significantly reduce survival ability of L. monocytogenes WT by 2 logs CFU/ml. Loss of sigL showed the greatest bile resistance among 16 strains tested, p<0.0001, (i.e., WT, four single alternative σ factor mutants, six double mutants, four triple mutants, and one quadruple mutant). To further investigate the role of σL in bile response, RNA-seq was conducted to compare the transcriptional profiles among L. monocytogenes 10403S ΔBCH triple mutant (lacking sigB, sigC, and sigH genes; expressing housekeeping σA and σL) and ΔBCHL quadruple mutant (lacking all alternative sigma factor genes; expressing only σA) strains under BHI and 1% bile conditions. A total of 216 and 176 differentially expressed genes (DEGs) were identified in BHI and bile, respectively. We confirmed that mpt operon was shown to be strongly activated by σL. Interestingly, more than 80% of DEGs were found to be negatively regulated in the presence of σL. This includes PrfA regulon and its mediated genes (i.e., hly, hpt, inlB, clpP, clpE, groL, and inlC) which were downregulated in response to bile in the presence of σL. This result suggests the potential negative role of σL on bile survival, and the roles of σL and σB might be in a seesaw model prior to host cell invasion.

Biliary Migration, Colonization, and Pathogenesis of O. viverrini Co-Infected with CagA+ Helicobacter pylori

Co-infection with the cagA strain of Helicobacter pylori exacerbates the pathology of human liver fluke Opisthorchis viverrini (OV) infection leading to cholangiocarcinoma. However, underlying mechanisms remain unclear. We report a significant increase in cagA-positive and cagA-negative H. pylori in the stomach, blood, bile, and in the OV worms of co-infected Syrian golden hamsters at one hour, three hours, and one month, post-infection, compared to hamsters infected with either OV or H. pylori alone. Except in the worms, H. pylori numbers declined at three months post-infection, particularly in the bile fluid of co-infected animals. Both strains of H. pylori were immunohistochemically detected in the tegument of the worm, as well as in the bile duct epithelium when co-infected with O. viverrine, but not in H. pylori infection alone. Interestingly, only the cagA-positive strain was detected in the gut of the worm. Co-infection between cagA-positive H. pylori and O. viverrini resulted in a more severe biliary pathology and decreased E-cadherin expression in vivo and in vitro than those of the cagA-negative strain. These data suggest that O. viverrini acts as a carrier of cagA-positive H. pylori and co-migrates to the bile ducts, whereas O. viverrini facilitates H. pylori colonization and enhances the biliary pathogenesis and carcinogenesis.

Digestive system

The chapter entitled ‘Digestive system’ opens with an overview of the anatomy of the abdomen, including the abdominal wall and peritoneal cavity, and the structure and histology of the major structures found therein, namely the intestinal tract (oesophagus, stomach, duodenum, jejunum, ileum, large intestine, rectum), spleen, liver, and pancreas. The functions of the gastrointestinal tract are described, covering motility, secretion (saliva, gastric acid, pancreatic fluid, bile, fluid, and electrolytes) and digestion/absorption of nutrients. Pathologies such as gastric and duodenal ulcers, malabsorption, intestinal obstruction, diarrhoea, and inflammatory diseases of the gut are considered, as are the immune functions of the gut. Similarly, the roles of the liver are covered, including protein synthesis, iron transport and storage, and detoxification, along with the effects of hepatic diseases such as hepatitis and cirrhosis.

Role of biliary drainage before pancreatoduodenectomy in treatment periampullary cancer

Introduction: Many studies show that biliary drainage prior to pancreatoduodenectomy increases the risk of biliarys bacterial infection. Our studys question: How does biliary drainage through ERCP before pancreatoduodenectomy affect the rate of post-operation infection? Materials and Methods: Prospective cohort study. All cases of periampullary cancer were scheduled to be performed standardize pancreatoduodenectomy from September 1st, 2018 to May 1st, 2019, at Cho Ray Hospital. Results: During the period of study, there were 38 cases that achieved criteria. There were 19 cases of ERCP with stenting before surgery, accounting for 50%, 19 cases of non-preoperative biliary drainage (accounting for 50%). The rate of positive culture with bacteria is common in patients with biliary tract stenting prior to surgery, the difference is statistically significant (p = 0.01). The incidence of surgical site infection is common among patients with biliary tract drainage prior to surgery and positive bile culture results for bacteria, but the difference is not statistically significant (p = 0.068). Conclusions: Biliary infection in patients with pancreatoduodenectomy treating periampullary cancer accounted for 60.5%. Bile duct stenting prior to surgery increases the risk of biliary tract infections and changes the type of bacteria in bile fluid. Keywords: Bilary drainage, pancreatoduodenectomy. Tóm tắt Đặt vấn đề: Dẫn lưu đường mật trước phẫu thuật cắt khối tá tụy làm tăng nguy cơ nhiễm khuẩn dịch mật. Câu hỏi nghiên cứu chúng tôi: ERCP dẫn lưu đường mật trước phẫu thuật ảnh hưởng thế nào đến tỉ lệ nhiễm trùng sau phẫu thuật cắt khối tá tụy. Phương pháp nghiên cứu: Nghiên cứu tiến cứu, mô tả hàng loạt ca. Thời gian từ 01 tháng 9 năm 2018 đến 01 tháng 5 năm 2019, các trường hợp cắt khối tá tụy thỏa tiêu chuẩn chọn bệnh tại Bệnh viện Chợ Rẫy. Kết quả: Có 38 trường hợp thỏa tiêu chuẩn chọn mẫu. Nghiên cứu ghi nhận có 19 trường hợp ERCP đặt stent dẫn lưu đường mật trước mổ (chiếm 50%), 19 trường hợp không dẫn lưu đường mật trước mổ (chiếm 50%). Tỉ lệ cấy dương tính với vi khuẩn thường gặp ở nhóm người bệnh có đặt stent dẫn lưu đường mật trước mổ, có ý nghĩ thống kê (p = 0,01). Tỉ lệ nhiễm khuẩn vết mổ thường gặp ở nhóm bệnh có đặt dẫn lưu đường mật trước mổ, sự khác biệt không có ý nghĩa thống kê (p = 0,068). Kết luận: Nhiễm khuẩn dịch mật sau phẫu thuật cắt khối tá tụy chiếm 60,5%. Đặt stent dẫn lưu đường mật trước mổ làm tăng nhiễm khuẩn dịch mật và làm thay đổi chủng vi khuẩn trong dịch mật.

Effects of Frozen Storage on Viability of Probiotics and Antioxidant Capacities of Synbiotic Riceberry and Sesame-Riceberry Milk Ice Creams

According to many recent studies, ice cream was found to be an effective carrier of probiotics along the human gastrointestinal tract. While probiotics have long been known to improve gut health, prebiotic-supplemented ice creams have demonstrated properties that could be linked to various health benefits and improvement of the gut microbiota. In this study, riceberry and sesame-riceberry milk ice creams were supplemented with inulin, Lactobacillus casei 01 and Lactobacillus acidophilus LA5 to examine the changes of probiotic populations in different formulations of ice cream. The survivability of probiotics after 60 days of frozen storage and the level of viable cell tolerance towards the simulated gastrointestinal environment were also assessed, followed by sensory evaluation with 100 untrained panelists and determination of chemical qualities of ice cream samples. Findings revealed L. casei 01 to be more resistant to frozen storage compared to L acidophilus LA5, whereas addition of sesame milk and inulin were shown to minimize levels of viable cell loss following environmental and mechanical stress, suggesting enhanced probiotic activity. Significant reductions in probiotic viability were observed for all ice cream samples, however higher survival rates were observed in prebiotic-supplemented samples prior to and after 60 days of frozen storage. Probiotic cell counts in all samples exceeded the minimum recommended value (6 log CFU/g). In simulated gastric and bile fluid, all samples illustrated a significant change in probiotic levels, which significantly decreased with increase time of exposure to acidic and basic conditions. Probiotic strains in samples containing riceberry, sesame and inulin demonstrated greatest survivability as observed by reduction in pH and increased total acidity, with increased antioxidant and phenolic contents. On the other hand, changes in physicochemical properties of ice cream lowered overall sensory scores in terms of color and flavor. This study contributes to future development and applications of riceberry and sesame for inducement of synbiotic effects in novel probiotic products.

Toxoplasma gondii-associated cholecystitis in a cat receiving immunosuppressive treatment

A 9-year-old female neutered domestic shorthair cat diagnosed with immune-mediated thrombocytopenia that was treated with prednisolone and cyclosporine, was presented for anorexia, vomiting, increased liver enzymes, and hyperbilirubinemia. Abdominal ultrasound revealed a markedly thickened gallbladder and common bile duct wall. Bile cytology detected severe neutrophilic inflammation and protozoal zoites. Suspected Toxoplasma gondii infection was confirmed by real-time PCR of bile. The cat was treated with clindamycin and ursodeoxycholic acid for 6 weeks, recovered and remained stable for 2 years despite ongoing immunosuppressive treatment. Thereafter, the cat was presented with suspicion of intestinal lymphoma, and recurrence of toxoplasmosis was diagnosed. Following treatment with clindamycin and prednisolone over 4 weeks the cat was euthanized. This is the first report of Toxoplasma gondii zoites detected in bile fluid from a cat with cholecystitis. Pathogenesis of toxoplasmosis in cats is still not fully understood. Although immunosuppression can represent a relevant predisposing factor, other factors, such as virulence of the parasite and genetic polymorphism of the host, can also play an important role. Toxoplasmosis should be included as a differential diagnosis in cats developing clinical signs of an inflammatory disease while receiving immunosuppressive treatment.

Alterations of the bile microbiome in primary sclerosing cholangitis

BackgroundPatients with primary sclerosing cholangitis (PSC) display an altered colonic microbiome compared with healthy controls. However, little is known on the bile duct microbiome and its interplay with bile acid metabolism in PSC.MethodsPatients with PSC (n=43) and controls without sclerosing cholangitis (n=22) requiring endoscopic retrograde cholangiography were included prospectively. Leading indications in controls were sporadic choledocholithiasis and papillary adenoma. A total of 260 biospecimens were collected from the oral cavity, duodenal fluid and mucosa and ductal bile. Microbiomes of the upper alimentary tract and ductal bile were profiled by sequencing the 16S-rRNA-encoding gene (V1–V2). Bile fluid bile acid composition was measured by high-performance liquid chromatography mass spectrometry and validated in an external cohort (n=20).ResultsThe bile fluid harboured a diverse microbiome that was distinct from the oral cavity, the duodenal fluid and duodenal mucosa communities. The upper alimentary tract microbiome differed between PSC patients and controls. However, the strongest differences between PSC patients and controls were observed in the ductal bile fluid, including reduced biodiversity (Shannon entropy, p=0.0127) and increase of pathogen Enterococcus faecalis (FDR=4.18×10−5) in PSC. Enterococcus abundance in ductal bile was strongly correlated with concentration of the noxious secondary bile acid taurolithocholic acid (r=0.60, p=0.0021).ConclusionPSC is characterised by an altered microbiome of the upper alimentary tract and bile ducts. Biliary dysbiosis is linked with increased concentrations of the proinflammatory and potentially cancerogenic agent taurolithocholic acid.