Using a ligate intestinal loop mouse model to investigate Clostridioides difficile adherence to the intestinal mucosa in aged mice

Interaction of Clostridioides difficile spores with the intestinal mucosa contributes to the persistence and recurrence of the infection. Advanced age is one of the main risk factors for C. difficile infection and recurrence of the disease. However, interaction of C. difficile spores with the intestinal mucosa during aging has not been evaluated. In the present work, using intestinal ligated loop technique in a mouse model, we analyzed C. difficile spore adherence and internalization to the ileum and colonic mucosa during aging. Additionally, we provide visual documentation of the critical steps of the procedure. Consequently, our data suggest that spore internalization in the ileum and colonic mucosa is higher in elderly mice rather than adults or young mice. Also, our data suggest that spore adherence to the ileum and colonic mucosa decreases with aging.

Cholera toxin induces intestinal secretion in an acute renal failure rat model

Background: Cholera is a life-threatening secretory diarrheal disease caused by Vibrio cholera bacterium. On the contrary, local and specific use of cholera toxin (CT) at a low concentration can cause controlled fluid secretion. In the study, we explored the secretory action of CT in the intestine of rats with acute renal failure (ARF). Methods: Closed intestinal loop experiments were performed in ARF rats treated with CT. Secreted fluid and serum were analyzed for various ¬solutes and electrolytes. The presence of K+, Na+, Cl-, urea and creatinine were monitored. Histopathology analysis was carried out to evaluate the effect of CT in liver, kidney, and intestinal tissues. Results: A reduction in the absorption of water and electrolytes was observed over time and a secretory response started to appear within hours of CT treatment. The fluid secretory response with entrapped electrolytes was profound in ARF rats. Histopathological analysis of CT exposed tissues revealed that apart from the tissue damage produced by acute renal failure, no CT induced cellular changes occurred. Conclusion: CT can be used as a secretagogue to induce fluid and electrolyte secretion in ARF rats. However, effective measures should be taken to avoid CT induced acidosis.

Litrre’s hernia: partially reduced inguinal hernia in a 3-year-old boy

This report examines the case of a 3-year-old child presenting with a 1-month history of swelling in the right groin. The boy had no associated nausea or vomiting, was afebrile and had had normal bowel movements. Attempts to reduce the swelling were only partially successful. Ultrasonography indicated the presence of turbid hydrocele and a hernia sac containing an intestinal loop. Accordingly, the patient underwent an urgent herniotomy. Exposing the hernia sac revealed 5 cm Meckel’s diverticulum, and the base of the diverticulum was resected from the inside of the hernia sac. The boy was discharged 4 days after the operation in good clinical condition. The presented case highlights the need to consider Littre’s hernia when dealing with partially reduced inguinal hernias in children with no general signs or evidence of intestinal obstruction.

Virulence of Cholera Toxin Gene-Positive Vibrio cholerae Non-O1/non-O139 Strains Isolated From Environmental Water in Kolkata, India

Cholera toxin (CT)-producing Vibrio cholerae O1 and O139 cause acute diarrheal disease and are proven etiological agents of cholera epidemics and pandemics. On the other hand, V. cholerae non-O1/non-O139 are designated as non-agglutinable (NAG) vibrios and are not associated with epidemic cholera. The majority of NAG vibrios do not possess the gene for CT (ctx). In this study, we isolated three NAG strains (strains No. 1, 2, and 3) with ctx from pond water in Kolkata, India, and examined their pathogenic properties. The enterotoxicity of the three NAG strains in vivo was examined using the rabbit ileal intestinal loop test. Strain No. 1 induced the accumulation of fluid in the loop, and the volume of fluid was reduced by simultaneous administration of anti-CT antiserum into the loop. The volume of fluid in the loop caused by strains No. 2 and 3 was small and undetectable, respectively. Then, we cultured these three strains in liquid medium in vitro at two temperatures, 25°C and 37°C, and examined the amount of CT accumulated in the culture supernatant. CT was accumulated in the culture supernatant of strain No.1 when the strain was cultured at 25°C, but that was low when cultured at 37°C. The CT amount accumulated in the culture supernatants of the No. 2 and No. 3 strains was extremely low at both temperature under culture conditions examined. In order to clarify the virulence properties of these strains, genome sequences of the three strains were analyzed. The analysis showed that there was no noticeable difference among three isolates both in the genes for virulence factors and regulatory genes of ctx. However, vibrio seventh pandemic island-II (VSP-II) was retained in strain No. 1, but not in strains No. 2 or 3. Furthermore, it was revealed that the genotype of the B subunit of CT in strain No. 1 was type 1 and those of strains No. 2 and 3 were type 8. Histopathological examination showed the disappearance of villi in intestinal tissue exposed to strain No. 1. In addition, fluid accumulated in the loop due to the action of strain No. 1 had hemolytic activity. This indicated that strain No. 1 may possesses virulence factors to induce severe syndrome when the strain infects humans, and that some strains of NAG vibrio inhabiting pond water in Kolkata have already acquired virulence, which can cause illness in humans. There is a possibility that these virulent NAG vibrios, which have acquired genes encoding factors involved in virulence of V. cholerae O1, may emerge in various parts of the world and cause epidemics in the future.

Mesalamine Reduces Intestinal ACE2 Expression Without Modifying SARS-CoV-2 Infection or Disease Severity in Mice.

Introduction: Coronavirus Disease 2019 (COVID-19) is an ongoing public health crisis that has sickened or precipitated death in millions. The etiologic agent of COVID-19, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), infects the intestinal epithelium, and can induce GI symptoms similar to the human inflammatory bowel diseases (IBD). An international surveillance epidemiology study (SECURE-IBD) reported that the standardized mortality ratio trends higher in IBD patients (1.5-1.8) and that mesalamine/sulfasalazine therapy correlates with poor outcome. The goal of our study was to experimentally address the relationship between mesalamine and SARS-CoV-2 entry, replication, and/or pathogenesis. Methods: Viral infection was performed with a chimeric vesicular stomatitis virus expressing SARS-CoV-2 spike protein and EGFP (VSV-SARS-CoV-2) and SARS-CoV-2 virus derived from an infectious cDNA clone of 2019n-CoV/USA_WA1/2020. Primary human ileal spheroids derived from healthy donors were grown as 3D spheroids or on 2D transwells. We assessed the effect of 10 mM mesalamine (Millipore Sigma) on viral RNA levels, as well as the expression of the SARS-CoV-2 receptor angiotensin II-converting enzyme 2 (ACE2), Transmembrane Serine Protease 2 (TMPRSS2), TMPRSS4, Cathepsin B (CTSB) and CTSL by qRT-PCR. 8-12 week old K18-ACE2 were treated orally with PBS or mesalamine at 200 mg/kg daily. Mice were inoculated intranasally with 1x10^3 FFU of SARS-CoV-2. Mice were weighed daily and viral titers were determined 7 days post infection (dpi) by qRT-PCR. For the intestinal viral entry model, VSV-SARS-CoV-2 was injected into a ligated intestinal loop of anesthetized K18-ACE2 mice and tissues were harvested 6 hours post-infection. Results: We found no change in viral RNA levels in human intestinal epithelial cells in response to mesalamine. Expression of ACE2 was reduced following mesalamine treatment in enteroids, while CTSL expression was increased. Mice receiving mesalamine lost weight at similar rates compared to mice receiving vehicle control. Mesalamine treatment did not change viral load in the lung, heart, or intestinal tissues harvested at 7 dpi. Pretreatment with mesalamine did not modulate intestinal entry of the chimeric VSV-SARS-CoV-2 in K18-ACE2 mice. Conclusions: Mesalamine did not alter viral entry, replication, or pathogenesis in vitro or in mouse models. Mesalamine treatment reduced expression of the viral receptor ACE2 while concurrently increasing CTSL expression in human ileum organoids.

Right-sided Bochdalek hernia in an adult with hepatic malformation and intestinal malrotation

Background Bochdalek hernia is a common congenital diaphragmatic defect that usually manifests with cardiopulmonary insufficiency in neonates. It is very rare in adults, and symptomatic cases are mostly left-sided. Diaphragmatic defects generally warrant immediate surgical intervention to reduce the risk of incarceration or strangulation of the displaced viscera. Case presentation A 47-year-old woman presented with dyspnea on exertion. Computed tomography revealed that a large part of the intestinal loop with superior mesenteric vessels and the right kidney were displaced into the right thoracic cavity. Preoperative three-dimensional (3D) simulation software visualized detailed anatomy of displaced viscera and the precise location and size of the diaphragmatic defect. She underwent elective surgery after concomitant pulmonary hypertension was stabilized preoperatively. The laparotomic approach was adopted. Malformation of the liver and the presence of intestinal malrotation were confirmed during the operation. The distal part of the duodenum, jejunum, ileum, colon, and right kidney were reduced into the abdominal cavity consecutively. A large-sized oval defect was closed with monofilament polypropylene mesh. No complications occurred postoperatively. Conclusion Symptomatic right-sided Bochdalek hernia in adults is exceedingly rare and is frequently accompanied by various visceral anomalies. Accurate diagnosis and appropriate surgical repair are crucial to prevent possible incarceration or strangulation. The preoperative 3D simulation provided comprehensive information on anatomy and concomitant anomalies and helped surgeons plan the operation meticulously and perform procedures safely.

Small Bowel Obstruction Caused by Tubo-Ovarian Abscess Following Chronic Pelvic Inflammatory Disease: A Case Report

BackgroundAlthough there are reports of small bowel obstruction (SBO) secondary to tubo-ovarian abscess (TOA), there have been no documented cases of unexpected SBO, multiple intestinal ruptures and adhesions in a patient with chronic PID followed by successful surgical treatment of TOA who was successfully treated by surgery after failure by conservative treatment.Case presentationA 40-year-old female was admitted with main complaint of abdominal pain and fever for six days. A pelvic mass measuring 6.37x7.85x9.04 cm and ascites at rectovaginal pouch were found despite local treatment with metronidazole and cefazolin. Laboratory tests revealed leukocytosis of 8.9x10^9/L with hyper-neutrocytophilia of 82.8%, C-reactive protein increase at 223 mg/L and Procalcitonin 0.14ng/L. The patient was diagnosed with an acute attack of chronic PID. Tests and body temperature improved after 4 days of IV antibiotics. However, two days later, the patient presented abdominal distension, poor appetite, and difficulty in defecation. Abdominal CT suggested possibility of bowel obstruction. Accordingly, an explorative laparoscopy was performed, revealing 500ml pale yellow ascites within the abdominal cavity. The intestinal tube was clearly dilated with poor peristalsis. Multiple intestinal ruptures and adhesions were found. Dense adhesion existed between the intestinal loop and posterior uterus wall, closing the rectouterine pouch. Pale yellow thick pus could be seen from the end of fallopian tube, and part of the right ovary showed serious pyosis. All the adhesions were split, ruptures were repaired and normal anatomy was restored. Postoperative pathology indicated acute and chronic inflammation of both fallopian tubes with focal abscess formation. The patient was discharged 15 days after operation and followed up at one month without any symptoms.ConclusionIn such cases, close attention should be paid to changes in the patient’s condition and lesion changes. Early laparoscopy is advised when there are significant clinical or CT scan signs of bowel obstruction in TOA patients. Precise predictors or a predictive model for the need of invasive intervention to TOA will require further investigation.

Multi-Omics Approach Reveals the Potential Core Vaccine Targets for the Emerging Foodborne Pathogen Campylobacter jejuni

Campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans around the world. The emergence of bacterial resistance is becoming more serious; therefore, development of new vaccines is considered to be an alternative strategy against drug-resistant pathogen. In this study, we investigated the pangenome of 173 C. jejuni strains and analyzed the phylogenesis and the virulence factor genes. In order to acquire a high-quality pangenome, genomic relatedness was firstly performed with average nucleotide identity (ANI) analyses, and an open pangenome of 8,041 gene families was obtained with the correct taxonomy genomes. Subsequently, the virulence property of the core genome was analyzed and 145 core virulence factor (VF) genes were obtained. Upon functional genomics and immunological analyses, five core VF proteins with high antigenicity were selected as potential core vaccine targets for humans. Furthermore, functional annotations indicated that these proteins are involved in important molecular functions and biological processes, such as adhesion, regulation, and secretion. In addition, transcriptome analysis in human cells and pig intestinal loop proved that these vaccine target genes are important in the virulence of C. jejuni in different hosts. Comprehensive pangenome and relevant animal experiments will facilitate discovering the potential core vaccine targets with improved efficiency in reverse vaccinology. Likewise, this study provided some insights into the genetic polymorphism and phylogeny of C. jejuni and discovered potential vaccine candidates for humans. Prospective development of new vaccines using the targets will be an alternative to the use of antibiotics and prevent the development of multidrug-resistant C. jejuni in humans and even other animals.

A ligated intestinal loop mouse model protocol to study the interactions of Clostridioides difficile spores with the intestinal mucosa during aging.

The interaction of the Clostridioides difficile spores with the intestinal mucosa contribute to the persistence and recurrence of the infection. Advanced age is one of the main risk factors to manifest C. difficile infection and recurrence. However, the interaction of C. difficile spores with the intestinal mucosa during aging has not been evaluated. In the present work, we provide a detailed protocol with all the critical information to perform an intestinal ligated loop. Using this technique in a mouse model, we evaluated C. difficile spore adherence and internalization to the ileum and colonic mucosa during aging. Consequently, our data suggest that spore internalization in the ileum and colonic mucosa is higher in elderly than in adults or young mice. Also, our data suggest that spore-adherence to the ileum and colonic mucosa decreases with aging.