Bacteriology and antimicrobial choice in hepatolithiasis

Bacterial culture and immunohistochemical detection of bacteria and endotoxin in cats with suppurative cholangitis-cholangiohepatitis syndrome

OBJECTIVE

To characterize the frequency and type of bacterial infection by culture- and immunohistochemical (IHC)-based methods and determine the impact of infection on clinical features and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS).

ANIMALS

168 client-owned cats with S-CCHS (cases).

PROCEDURES

Clinical features, bacterial culture results, culture-inoculate sources, and survival details were recorded. Cases were subcategorized by comorbidity (extrahepatic bile duct obstruction, cholelithiasis, cholecystitis, ductal plate malformation, biopsy-confirmed inflammatory bowel disease, and biopsy-confirmed pancreatitis) or treatment by cholecystectomy or cholecystoenterostomy. Culture results, bacterial isolates, Gram-stain characteristics, and IHC staining were compared among comorbidities. Lipoteichoic acid IHC staining detected gram-positive bacterial cell wall components, and toll-like receptor expression IHC reflected pathologic endotoxin (gram-negative bacteria) exposure.

RESULTS

Clinical features were similar among cases except for more frequent abdominal pain and lethargy in cats with positive culture results and pyrexia, abdominal pain, and hepatomegaly for cats with polymicrobial infections. Bacteria were cultured in 93 of 135 (69%) cats, with common isolates including Enterococcus spp and Escherichia coli. IHC staining was positive in 142 of 151 (94%) cats (lipoteichoic acid, 107/142 [75%]; toll-like receptor 4, 99/142 [70%]). With in-parallel interpretation of culture and IHC-based bacterial detection, 154 of 166 (93%) cats had bacterial infections (gram-positive, 118/154 [77%]; gram-negative, 111/154 [72%]; polymicrobial, 79/154 [51%]). Greater frequency of bacterial isolation occurred with combined tissue, bile, and crushed cholelith inoculates. Infection and gram-positive bacterial isolates were associated with significantly shorter long-term survival times.

CLINICAL RELEVANCE

S-CCHS was associated with bacterial infection, pathologic endotoxin exposure, and frequent polymicrobial infection in cats. Combined tissue inoculates improved culture detection of associated bacteria.

Canine intrahepatic biliary disease - what have we learned?

The intrahepatic biliary tract is essential for physiologic homeostasis. Disease that results in aberrant function can have serious deleterious consequences and result in considerable morbidity and mortality. This review aimed to summarise clinically relevant updates on intrahepatic biliary disorders in dogs including human corollaries.

Modified percutaneous transhepatic papillary balloon dilation for patients with refractory hepatolithiasis

BACKGROUND

Some patients with hepatolithiasis cannot tolerate surgery due to severe cardiac or pulmonary comorbidities, or cannot be endoscopically treated because of altered gastrointestinal anatomies.

AIM

To propose a modified percutaneous transhepatic papillary balloon dilation procedure, and evaluate the clinical efficacy and safety of this modality.

METHODS

Data from 21 consecutive patients who underwent modified percutaneous transhepatic papillary balloon dilation with hepatolithiasis were retrospectively analyzed. Using auxiliary devices, intrahepatic bile duct stones were pushed into the common bile duct and expelled into the duodenum with an inflated balloon catheter. The outcomes recorded included success rate, procedure time, hospital stay, causes of failure, and procedure-related complications. Patients with possible long-term complications were followed up for 2 years.

RESULTS

Intrahepatic bile duct stones were successfully removed in 20 (95.23%) patients. Mean procedure time was 65.8 ± 5.3 min. Mean hospital stay was 10.7 ± 1.5 d. No pancreatitis, gastrointestinal, or biliary duct perforation was observed. All patients were followed up for 2 years, and there was no evidence of reflux cholangitis or calculi recurrence.

CONCLUSION

Modified percutaneous transhepatic papillary balloon dilation was feasible and safe with a small number of patients with hepatolithiasis, and may be a treatment option in patients with severe comorbidities or in patients in whom endoscopic procedure was not successful.

Spontaneous cholecystopleural fistula leading to biliothorax and sepsis in a cat

Case summary

A 13-year-old spayed female domestic shorthair cat presented with pleural effusion and suspected triaditis. Intake vitals and leukocytosis were consistent with a diagnosis of systemic inflammatory response syndrome. Biochemical analysis confirmed a pleural fluid-to-serum bile ratio consistent with a diagnosis of biliothorax. Abdominal ultrasound failed to identify a definitive gall bladder but noted a hypoechoic tubular structure ventral to the liver and contacting the diaphragm. Thoracic ultrasound identified a hyperechoic structure contacting the diaphragm at the same location. Thoracoabdominal CT scan identified a fluid-dense tubular structure extending from ventral to the liver, through a diaphragmatic defect and directly communicating with the pleural space, suspected to be an abnormal gall bladder. The cat was humanely euthanized, and post-mortem analysis confirmed a cholecystopleural fistula arising from the gall bladder with multifocal abscesses, mixed inflammatory hepatic infiltrates and small-cell gastrointestinal lymphoma. Culture of the abscess isolated Parabacteroides merdae, meeting the reported feline criteria for sepsis.

Relevance and novel information

To our knowledge, spontaneous cholecystopleural fistula formation leading to biliothorax and sepsis has not been previously reported in the cat. This case highlights a novel sequela of gall bladder disease in this species, and biliothorax should be a differential diagnosis for pleural effusion in cats with evidence of cholecystitis or triaditis.

β-Defensin 1 Is Prominent in the Liver and Induced During Cholestasis by Bilirubin and Bile Acids via Farnesoid X Receptor and Constitutive Androstane Receptor

Background & aims

Knowledge about innate antimicrobial defense of the liver is limited. We investigated hepatic expression and regulation of antimicrobial peptides with focus on the human beta defensin-1 (hBD-1).

Methods

Radial diffusion assay was used to analyze antimicrobial activity of liver tissue. Different defensins including hBD-1 and its activator thioredoxin-1 (TXN) were analyzed in healthy and cholestatic liver samples by qPCR and immunostaining. Regulation of hBD-1 expression was studied in vitro and in vivo using bile duct-ligated mice. Regulation of hBD-1 via bilirubin and bile acids (BAs) was studied using siRNA.

Results

We found strong antimicrobial activity of liver tissue against Escherichia coli. As a potential mediator of this antimicrobial activity we detected high expression of hBD-1 and TXN in hepatocytes, whereas other defensins were minimally expressed. Using a specific antibody for the reduced, antimicrobially active form of hBD-1 we found hBD-1 in co-localization with TXN within hepatocytes. hBD-1 was upregulated in cholestasis in a graded fashion. In cholestatic mice hepatic AMP expression (Defb-1 and Hamp) was enhanced. Bilirubin and BAs were able to induce hBD-1 in hepatic cell cultures in vitro. Treatment with siRNA and/or agonists demonstrated that the farnesoid X receptor (FXR) mediates basal expression of hBD-1, whereas both constitutive androstane receptor (CAR) and FXR seem to be responsible for the induction of hBD-1 by bilirubin.

Conclusion

hBD-1 is prominently expressed in hepatocytes. It is induced during cholestasis through bilirubin and BAs, mediated by CAR and especially FXR. Reduction by TXN activates hBD-1 to a potential key player in innate antimicrobial defense of the liver.

Effective Treatment of Chronic Proliferative Cholangitis by Local Gentamicin Infusion in Rabbits

Background

Hepatolithiasis is highly prevalent in East Asia characterized by the presence of gallstones in the biliary ducts of the liver. Surgical resection is the potentially curative treatment but bears a high risk of stone recurrence and biliary restenosis. This is closely related to the universal presence of chronic proliferative cholangitis (CPC) in the majority of patients. Recent evidence has indicated the association of bacterial infection with the development of CPC in hepatolithiasis. Thus, this study aims to investigate the feasibility and efficacy of local infusion of gentamicin (an antibiotic) for the treatment of CPC in a rabbit model.

Methods

The rabbit CPC model was established based on previously published protocols. Bile duct samples were collected from gentamicin-treated or control animals for pathological and molecular characterization.

Results

Histologically, the hyperplasia of biliary epithelium and submucosal glands were inhibited and the thickness of the bile duct wall was significantly decreased after gentamicin therapy. Consistently, the percentage of proliferating cells marked by ki67 was significantly reduced by the treatment. More importantly, this treatment inhibited interleukin 2 production, an essential inflammatory cytokine, and the enzyme activity of endogenous β-Glucuronidase, a key factor in the formation of bile pigment.

Conclusions

Local gentamicin infusion effectively inhibits the inflammation, cell proliferation, and lithogenesis in a rabbit model of CPC. This approach represents a potential treatment for CPC and thus prevents recurrent hepatolithiasis.

Pyogenic liver abscess related to intrahepatic bile duct stones: Difficulties in infectious control and diagnosis of concomitant cholangiocarcinoma

BACKGROUND AND AIM

Cholangitis, bacteremia, and pyogenic liver abscess (PLA) can be often caused by intrahepatic bile ducts stone (IBDS), which is endemic to South-East Asia. The association between IBDS and cholangiocarcinoma has been well recognized. Concomitant cholangiocarcinoma in the PLA related to IBDS is often missed.

METHODS

A case-control study consisting of 64 patients with PLA related to IBDS and 256 control patients with PLA not related to IBDS was used to investigate clinical features of PLA and incidence of concomitant cholangiocarcinoma in patients with PLA related to IBDS.

RESULTS

The main imaging manifestations of PLA related to IBDS was cystic-solid lesions and solid lesions. Of seven patients (10.9%) with pathology-proven cholangiocarcinoma in the same area of PLA related to IBDS among 64 patients, only two patients were initially diagnosed as having concomitant cholangiocarcinoma by biopsy, and other five patients diagnosed as acute inflammatory lesion. Within 60 days after onset, the infection-related death rate and recurrence rate in patients with PLA related to IBDS were 12.9% and 20.3%, respectively, whereas in patients with PLA not related to IBDS were 3.9% and 3.1%, respectively. Only 25% of patients with PLA related to IBDS underwent surgery after admission. The main pathogens in PLA patients related to IBDS were Escherichia coli and extended-spectrum beta-lactamase-producing Enterobacteriaceae.

CONCLUSIONS

The imaging manifestations of PLA related to IBDS often present cystic-solid or solid lesions. PLA related to IBDS is characterized by high rate of recurrence and infection-related death, difficulty in diagnosis of concomitant cholangicarcinoma.

How the biliary tree maintains immune tolerance?

The liver is a vital organ with distinctive anatomy, histology and heterogeneous cell populations. These characteristics are of particular importance in maintaining immune homeostasis within the liver microenvironments, notably the biliary tree. Cholangiocytes are the first line of defense of the biliary tree against foreign substances, and are equipped to participate through various immunological pathways. Indeed, cholangiocytes protect against pathogens by TLRs-related signaling; maintain tolerance by expression of IRAK-M and PPARγ; limit immune response by inducing apoptosis of leukocytes; present antigen by expressing human leukocyte antigen molecules and costimulatory molecules; recruit leukocytes to the target site by expressing cytokines and chemokines. However, breach of tolerance in the biliary tree results in various cholangiopathies, exemplified by primary biliary cholangitis, primary sclerosing cholangitis and biliary atresia. Lessons learned from immune tolerance of the biliary tree will provide the basis for the development of effective therapeutic approaches against autoimmune biliary tract diseases. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Biliary diseases as main causes of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae

BACKGROUND & AIMS

Little is known about aetiology and morbidity and clinical characteristics of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae.

METHODS

An analysis between pyogenic liver abscess patients caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates and those caused by non-extended-spectrum beta-lactamase-producing Enterobacteriaceae was performed.

RESULTS

Among 817 pyogenic liver abscess patients, there were 176 patients (21.5%) with pyogenic liver abscess of biliary origin, and 67 pyogenic liver abscess patients (8.2%) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates (mainly Escherichia coli and Klebsiella pneumoniae). Of 176 pyogenic liver abscess patients related to biliary disorders, there were 48 pyogenic liver abscess patients (27.3%) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Within 67 pyogenic liver abscess patients caused by Enterobacteriaceae expressing extended-spectrum beta-lactamases, the occurrences of 48 pyogenic liver abscess patients (71.6%) were associated with biliary disorders. When compared with pyogenic liver abscess patients caused by non-extended-spectrum beta-lactamase-producing Enterobacteriaceae, there were significantly greater incidences of polymicrobial infections, bacteremia, pulmonary infection, recurrence and death in pyogenic liver abscess patients caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Carbapenems remain mainstay drugs against extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae. Independent risk factors for occurrence of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae were biliary disorders including extra- and intrahepatic cholangiolithiasis and an abnormal bilioenteric communication between bile and gut, a treatment history of malignancy such as operation and chemotherapy, pulmonary infection, and diabetes mellitus.

CONCLUSIONS

Pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates mainly occurs in patients with biliary disorders or with a treatment history of malignancy. The mainstay of treatment remains carbapenems in combination with adequate aspiration or drainage.

Post-procedural Care in Interventional Radiology: What Every Interventional Radiologist Should Know-Part I: Standard Post-procedural Instructions and Follow-Up Care

Interventional radiology (IR) has evolved into a full-fledged clinical specialty with attendant patient care responsibilities. Success in IR now requires development of a full clinical practice, including consultations, inpatient admitting privileges, and an outpatient clinic. In addition to technical excellence and innovation, maintaining a comprehensive practice is imperative for interventional radiologists to compete successfully for patients and referral bases. A structured approach to periprocedural care, including routine follow-up and early identification and management of complications, facilitates efficient and thorough management with an emphasis on quality and patient safety.

Epidemiology and Resistance Patterns of Bacterial and Fungal Colonization of Biliary Plastic Stents: A Prospective Cohort Study

Background

Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance.

Methods

Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH).

Results

Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective isolates.

Conclusions

Enterococci and Candida species play an important role in the microbial colonization of biliary stents. Therefore, empirical antimicrobial treatment of stent-associated cholangitis should be guided toward enterococci, Enterobacteriaceae, streptococci, anaerobes, and Candida. To determine causative pathogens, an accurate microbiological analysis of the extracted stent(s) may be helpful.

Pathogenesis and Management of Hepatolithiasis: A Report of Two Cases

Hepatolithiasis or primary intrahepatic stones are prevalent in the Far-East countries such as Korea, Japan and Taiwan. It has been associated with helminthiasis, bacterial infections, environmental and dietary factors. Despite high prevalence of helminthiasis like ascariasis, poor environmental condition and low protein diet, India and Middle-East countries have a low incidence of hepatolithiasis. We report two cases of hepatolithiasis associated with bacterial infections and were surgically managed. The first case is a 45-year-old female presenting with upper abdominal pain and fever. She had multiple calculi in intrahepatic biliary radicles, common bile duct, common hepatic duct and gall bladder. She was managed by cholecystectomy, left lateral liver sectionectomy, choledochoscopy assisted stone clearance of the residual liver and Roux-en-Y hepatico-jejunostomy. The second case is a 60-year-old female presenting with epigastric pain and fever and past history of cholecystectomy for cholelithiasis. She had multiple right and left intrahepatic calculi and managed by left lateral liver sectionectomy with excision of CBD and Roux-en-Y hepatico-jejunostomy. Both the cases showed growth of bacteria in the culture of the intraoperatively collected bile.

Spectrum and treatment of anaerobic infections

Anaerobes are the most predominant components of the normal human skin and mucous membranes bacterial flora, and are a frequent cause of endogenous bacterial infections. Anaerobic infections can occur in all body locations: the central nervous system, oral cavity, head and neck, chest, abdomen, pelvis, skin, and soft tissues. Treatment of anaerobic infection is complicated by their slow growth in culture, by their polymicrobial nature and by their growing resistance to antimicrobials. Antimicrobial therapy is frequently the only form of therapy needed, whereas in others it is an important adjunct to drainage and surgery. Because anaerobes generally are isolated mixed with aerobes, the antimicrobial chosen should provide for adequate coverage of both. The most effective antimicrobials against anaerobes are: metronidazole, the carbapenems (imipenem, meropenem, doripenem, ertapenem), chloramphenicol, the combinations of a penicillin and a beta-lactamase inhibitors (ampicillin or ticarcillin plus clavulanate, amoxicillin plus sulbactam, piperacillin plus tazobactam), tigecycline, cefoxitin and clindamycin.

Relationship of Gallbladder Perforation and Bacteriobilia with Occurrence of Surgical Site Infections following Laparoscopic Cholecystectomy

Aim. To assess the occurrence of SSIs in patients with spillage of gallbladder contents and bacteriobilia during laparoscopic cholecystectomy. Methods. We evaluated 113 patients who underwent laparoscopic cholecystectomy between September 2013 and April 2015. The SSIs and their relationship with gallbladder rupture and bacteriobilia were assessed. Results. The mean age of patients developing SSIs was 45.57 ± 8.89 years. 18 patients (16%) had spillage of bile from the gallbladder. Percentage of SSIs overall was 6%, while percentage of SSIs in gallbladder content spillage was 5.5%. Organism profile of the culture from surgical site showed monomicrobial infection: 58% Staphylococcus aureus, 14% Pseudomonas, and 14% E. coli. The occurrence of SSIs in patients with bacteriobilia was 16% as compared to 2% in patients without bacteriobilia. Conclusions. Gallbladder content spillage is not a significant risk factor leading to increase in SSIs. The occurrence of SSIs is significantly higher in patients with bacteriobilia.

Biliary endoprosthesis: a prospective analysis of bacterial colonization and risk factors for sludge formation

Bacterial colonization of biliary stents is one of the driving forces behind sludge formation which may result in stent occlusion. Major focus of the study was to analyze the spectrum and number of microorganisms in relation to the indwelling time of stents and the risk factors for sludge formation. 343 stents were sonicated to optimize the bacterial release from the biofilm and identified by matrix-associated laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF). 2283 bacteria were analyzed in total. The most prevalent microorganisms were Enterococcus species (spp.) (504;22%), followed by Klebsiella spp. (218;10%) and Candida spp. (188;8%). Colonization of the stents mainly began with aerobic gram-positive bacteria (43/49;88%) and Candida spp. (25/49;51%), whereas stents with an indwelling time>60 days(d) showed an almost equal colonization rate by aerobic gram-negative (176/184;96%) and aerobic gram-positive bacteria (183/184;99%) and a high proportion of anaerobes (127/184;69%). Compared to stents without sludge, more Clostridium spp. [(P = 0.02; Odds Ratio (OR): 2.4; 95% confidence interval (95%CI): (1.1-4.9)]) and Staphylococcus spp. [(P = 0.03; OR (95%CI): 4.3 (1.1-16.5)] were cultured from stents with sludge. Multivariate analysis revealed a significant relationship between the number of microorganisms [P<0.01; OR (95%CI): 1.3(1.1-1.5)], the indwelling time [P<0.01; 1-15 d vs. 20-59 d: OR (95%CI): 5.6(1.4-22), 1-15 d vs. 60-3087 d: OR (95% CI): 9.5(2.5-35.7)], the presence of sideholes [P<0.01; OR (95%CI): 3.5(1.6-7.9)] and the occurrence of sludge. Stent occlusion was found in 70/343(20%) stents. In 35% of cases, stent occlusion resulted in a cholangitis or cholestasis. In conclusion, microbial colonization of the stents changed with the indwelling time. Sludge was associated with an altered spectrum and an increasing number of microorganisms, a long indwelling time and the presence of sideholes. Interestingly, stent occlusion did not necessarily lead to a symptomatic biliary obstruction.

Oriental cholangiohepatitis - is our surgery appropriate?

Oriental cholangiohepatitis, or recurrent pyogenic cholangitis is only noted in certain parts of the world, especially South East Asia. Due to increasing immigration the disease is now being seen in western countries also. Treating physicians may face difficulty in managing such cases due to lack of exposure. Furthermore management of such cases is not standardized because of lack of a universally accepted classification system. Here we review the disease and share our long experience with management of these patients.

Bacterial spectrum of hepatolithiasis with biliary tract infection

Hepatolithiasis is prevalent in Far East and Southeast Asian countries, and it is usually associated with cholestasis and bacterial infection and causes repeated episodes of acute cholangitis. If not properly treated, hepatolithiasis can cause serious complications and even death. In addition to removal of stones and management of cholestasis by surgery or interventional radiological treatment, timely and effective antibiotic treatment also plays a crucial role in the treatment of hepatolithiasis. This paper aims to clarify the bacterial spectrum of hepatolithiasis with biliary tract infection. By reviewing relevant papers published over the past 30 years, we discovered that both gram-negative bacteria, in which E. coli was most frequent, followed by Klebsiella sp and Pseudomonas sp, and gram-positive bacteria, mainly Enterococcus sp, were responsible for biliary tract infection. Bacteroides sp and Clostridium were most frequently found anaerobes. Sometimes, anaerobes were found together with aerobes. The purpose of this article is to elaborate the bacterial spectrum of hepatolithiasis with biliary tract infection and provide the appropriate choice of antibiotic therapy.

Advances in cholangiocyte immunobiology

Cholangiocytes, or bile duct epithelia, were once thought to be the simple lining of the conduit system comprising the intra- and extrahepatic bile ducts. Growing experimental evidence demonstrated that cholangiocytes are in fact the first line of defense of the biliary system against foreign substances. Experimental advances in recent years have unveiled previously unknown roles of cholangiocytes in both innate and adaptive immune responses. Cholangiocytes can release inflammatory modulators in a regulated fashion. Moreover, they express specialized pattern-recognizing molecules that identify microbial components and activate intracellular signaling cascades leading to a variety of downstream responses. The cytokines secreted by cholangiocytes, in conjunction with the adhesion molecules expressed on their surface, play a role in recruitment, localization, and modulation of immune responses in the liver and biliary tract. Cholangiocyte survival and function is further modulated by cytokines and inflammatory mediators secreted by immune cells and cholangiocytes themselves. Because cholangiocytes act as professional APCs via expression of major histocompatibility complex antigens and secrete antimicrobial peptides in bile, their role in response to biliary infection is critical. Finally, because cholangiocytes release mediators critical to myofibroblastic differentiation of portal fibroblasts and hepatic stellate cells, cholangiocytes may be essential in the pathogenesis of biliary cirrhosis.

Prophylactic antibiotic guidelines in modern interventional radiology practice

Modern interventional radiology practice is continuously evolving. Developments include increases in the number of central venous catheter placements and tumor treatments (uterine fibroid therapy, radio- and chemoembolization of liver tumor, percutaneous radiofrequency and cryoablation), and new procedures such as abdominal aortic aneurysm stent-graft repair, vertebroplasty, kyphoplasty, and varicose vein therapies. There have also been recent advancements in standard biliary and urinary drainage procedures, percutaneous gastrointestinal feeding tube placement, and transjugular intrahepatic portosystemic shunts. Prophylactic antibiotics have become the standard of care in many departments, with little clinical data to support its wide acceptance. The rise in antibiotic-resistant strains of organisms in all hospitals worldwide have forced every department to question the use of prophylactic antibiotics. The authors review the evidence behind use of prophylactic antibiotics in standard interventional radiology procedures, as well as in newer procedures that have only recently been incorporated into interventional radiology practice.

Cholangiopathy with respect to biliary innate immunity

Biliary innate immunity is involved in the pathogenesis of cholangiopathies in cases of biliary disease. Cholangiocytes possess Toll-like receptors (TLRs) which recognize pathogen-associated molecular patterns (PAMPs) and play a pivotal role in the innate immune response. Tolerance to bacterial PAMPs such as lipopolysaccharides is also important to maintain homeostasis in the biliary tree, but tolerance to double-stranded RNA (dsRNA) is not found. Moreover, in primary biliary cirrhosis (PBC) and biliary atresia, biliary innate immunity is closely associated with the dysregulation of the periductal cytokine milieu and the induction of biliary apoptosis and epithelial-mesenchymal transition (EMT), forming in disease-specific cholangiopathy. Biliary innate immunity is associated with the pathogenesis of various cholangiopathies in biliary diseases as well as biliary defense systems.

Microbiology and antibiotic susceptibility of organisms in bile cultures from patients with and without cholangitis at an Asian academic medical center

PURPOSE

To review the epidemiology of microbial isolates from bile cultures taken from patients with and without cholangitis admitted to an Asian academic medical center in order to compare antimicrobial sensitivities and to make recommendations for empiric antimicrobial therapy of patients with cholangitis in the Philippines.

METHODS

Routine aerobic bile culture results and corresponding clinical abstracts of surgical patients admitted to an academic medical center over a three-year period were analyzed.

RESULTS

The series consisted of 125 patients, 77 with cholangitis (62%) and 48 (38%) without, which was determined according to the Tokyo Guidelines. Patients with cholangitis were significantly more likely to have positive bile cultures (p = 0.012). Gram-negative bacilli were the most common isolates in both patients with (94%) and patients without (95%) cholangitis. For both groups, Escherichia coli (36%) had greatest sensitivity to amikacin, cefepime, ceftriaxone, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam; Klebsiella pneumoniae (16%) had greatest sensitivity to amikacin, cefepime, ceftriaxone, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam; and Pseudomonas aeruginosa (12.5%) was most sensitive to cefepime, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam.

CONCLUSIONS

Gram-negative bacilli (or Enterobacteriaceae) (E. coli, K. pneumoniae, P. aeruginosa, and Enterobacter cloacae) were the most common aerobic microbial isolates in bile cultures from patients with cholangitis in the Philippines. Their antimicrobial susceptibility patterns suggest that imipenem-cilastatin (sensitivity 100%), meropenem (100%), amikacin (90-100%), cefepime (75%-100%), ceftriaxone (75%-100%), gentamicin (67%-100%), and piperacillin-tazobactam (50%-100%) would be the most effective antimicrobials for both groups. However, the authors echo the caution from the Surgical Infection Society/Infectious Diseases Society of America against using aminoglycosides as empiric drugs when safer and equally effective regimens are available.

Biliary innate immunity: function and modulation

Biliary innate immunity is involved in the pathogenesis of cholangiopathies in patients with primary biliary cirrhosis (PBC) and biliary atresia. Biliary epithelial cells possess an innate immune system consisting of the Toll-like receptor (TLR) family and recognize pathogen-associated molecular patterns (PAMPs). Tolerance to bacterial PAMPs such as lipopolysaccharides is also important to maintain homeostasis in the biliary tree, but tolerance to double-stranded RNA (dsRNA) is not found. In PBC, CD4-positive Th17 cells characterized by the secretion of IL-17 are implicated in the chronic inflammation of bile ducts and the presence of Th17 cells around bile ducts is causally associated with the biliary innate immune responses to PAMPs. Moreover, a negative regulator of intracellular TLR signaling, peroxisome proliferator-activated receptor-γ (PPARγ), is involved in the pathogenesis of cholangitis. Immunosuppression using PPARγ ligands may help to attenuate the bile duct damage in PBC patients. In biliary atresia characterized by a progressive, inflammatory, and sclerosing cholangiopathy, dsRNA viruses are speculated to be an etiological agent and to directly induce enhanced biliary apoptosis via the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Moreover, the epithelial-mesenchymal transition (EMT) of biliary epithelial cells is also evoked by the biliary innate immune response to dsRNA.

Significance of controlling chronic proliferative cholangitis in the treatment of hepatolithiasis

BACKGROUND

Recently, high stone recurrence and biliary restenosis rates in hepatolithiasis patients have been confirmed to be closely related to chronic proliferative cholangitis (CPC). However, the effective management of CPC has not yet been established.

METHODS AND RESULTS

A vicious cycle exists between the presence of intrahepatic calculi and CPC: both the stone itself and secondary biliary infection can stimulate persistent hyperplasia in the biliary duct wall, leading to the occurrence of CPC and biliary stricture. The recurrent attacks of CPC will, in turn, facilitate new stone formation via mucoglycoprotein production, or induced biliary stricture and cholestasis. Thus, even when the stone is completely removed and the biliary tract stenosis is corrected, residual CPC will persist and progress, with an underlying risk for postoperative stone recurrence and biliary tract restenosis. Therefore, the perfect hepatolithiasis treatment would target stone removal and correction of the biliary tract stricture, as well as control of postoperative residual CPC. In fact, CPC, the management of which has been traditionally ignored, is the key to breaking this vicious cycle.

CONCLUSIONS

Overall, the subsequent treatment of residual CPC after operation or choledochoscopic lithotomy would be helpful to decrease postoperative stone recurrence and the rate of biliary restenosis. Adding such treatment would reduce the incidence of surgical reintervention and choledochoscopic lithotomy, and it would also improve the postoperative hepatolithiasis outlook.

The immunobiology of cholangiocytes

Cholangiocytes, the epithelial cells lining bile ducts, provide the first line of defense against lumenal microbes in the biliary system. Recent advances in biliary immunity indicate that cholangiocytes express a variety of pathogen-recognition receptors and can activate a set of intracellular signaling cascades to initiate a profound antimicrobial defense, including release of proinflammatory cytokines and chemokines, production of antimicrobial peptides and maintenance of biliary epithelial integrity. Cholangiocytes also interact with other cell types in the liver (for example, lymphocytes and Kupffer cells) through expression and release of adhesion molecules and immune mediators. Subsequently, through an intricate feedback mechanism involving both epithelial and other liver cells, a set of intracellular signaling pathways are activated to regulate the functional state of cholangiocyte responses during microbial infection. Thus, cholangiocytes are actively involved in mucosal immunity of the biliary system and represent a fine-tuned, integral component of liver immunity.

Induction of innate immune response and absence of subsequent tolerance to dsRNA in biliary epithelial cells relate to the pathogenesis of biliary atresia

BACKGROUND/AIMS

Biliary epithelial cells (BECs) possess negative regulatory mechanisms of Toll-like receptor (TLR)-based tolerance to bacteria (e.g. endotoxin tolerance). Viral infections of the Reoviridae genus with a dsRNA genome are suspected to be part of the aetiology of biliary atresia (BA), but the negative biliary mechanisms remain unexplored.

METHODS

Cultured human intrahepatic BECs (HIBECs) pretreated with polyinosinic-polycytidylic acid [poly(I:C)] (a synthetic analogue of viral dsRNA) for 24 h were exposed to poly(I:C) in fresh medium. The activation of nuclear factor-kappaB (NF-kappaB) and the expression of myxovirus resistance protein A (MxA) and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) mRNAs were evaluated. Moreover, after the pretreatment, the transition of these molecules was examined in poly(I:C)-free conditions.

RESULTS

Treatment with poly(I:C) significantly upregulated NF-kappaB activity in fresh HIBECs, and pretreatment failed to show tolerance to poly(I:C). The production of MxA and TRAIL was also preserved. Moreover, upregulation in the pretreated HIBECs was well preserved in poly(I:C)-free medium for at least 72 h.

CONCLUSIONS

BECs fail to show tolerance to poly(I:C), and once innate immunity is activated it is sustained in poly(I:C)-free conditions, suggesting that the initiation of the immune response to dsRNA in HIBECs and its presence after the clearance of virus are closely associated with the progression of BA.

Interaction of Toll-like receptors with bacterial components induces expression of CDX2 and MUC2 in rat biliary epithelium in vivo and in culture

The mechanism of transformation of biliary epithelium leading to intestinal metaplasia, which is significantly involved in biliary diseases, remains unclear. CDX2, an intestine-specific transcription factor, is thought to regulate intestinal mucin MUC2 (mucus core protein) expression. We took advantage of polycystic kidney (PCK) rats as a model of chronic suppurative cholangitis with intestinal metaplasia and of cultured biliary epithelial cells (BECs) from PCK rats to clarify the causal relation between bacterial components such as pathogen-associated molecular patterns (PAMPs) and the development of intestinal metaplasia of bile ducts. Histological, immunohistochemical, and in situ hybridization studies were conducted in PCK rat livers. In cultured BECs, CDX2 and MUC2 were expressed following treatment with PAMPs and inhibitors (anti-Toll-like receptor (TLR)2/TLR4 antibody, nuclear factor-kappaB (NF-kappaB) inhibitor MG132). Chronic suppurative cholangitis with intestinal metaplasia developed as the PCK rats aged, and intestinal metaplasia and aberrant CDX2 and MUC2 expression developed in parallel. Intraluminal bacteria and the expression of TLR2 and TLR4 in BECs were demonstrated in the bile ducts, showing chronic suppurative cholangitis. In cultured BECs, treatment with PAMPs induced upregulation of CDX2 and MUC2 expression, and this effect was abolished by pretreatment with anti-TLR2 and anti-TLR4 antibody and MG132. A knockdown of CDX2 by CDX2 small interfering RNA inhibited MUC2 expression in cultured BECs induced by PAMPs, and transfection of CDX2 expression vector induced MUC2 expression. In conclusion, bacterial components may induce upregulation of the CDX2 expression followed by MUC2 expression via TLR and the NF-kappaB system in cultured BECs, and could be related to the development of intestinal metaplasia of the bile ducts.

Role of ciprofloxacin in patients with cholestasis after endoscopic retrograde cholangiopancreatography

AIM: To determine the role of ciprofloxacin in reducing cholangitis in cholestatic patients with adequate biliary drainage after endoscopic retrograde cholangiopancreatography (ERCP).

METHODS: A randomized, controlled trial was performed in 48 cholestatic patients at Rajavithi Hospital (Tertiary Referral Center for ERCP: 600 cases per year). All the 48 patients received 200 mg ciprofloxacin intravenous injection for 30 min before starting any procedures, and then were randomly divided in two groups. Twenty-two patients in study group continually received ciprofloxacin until 48 h after ERCP. Causes of biliary obstruction, bacteriology of bile and blood (in cholangitis) and clinical cholangitis were recorded.

RESULTS: Forty-eight patients were enrolled and divided into continuous ciprofloxacin treatment group (n = 22) and discontinuous ciprofloxacin treatment group (n = 26). During ERCP, stones were found in 22 patients, malignant diseases in 24 patients and other pathologic lesions in 5 patients. One (4.5%) of the 22 patients who received ciprofloxacin and 2 (6.3%) of the 26 patients who discontinued ciprofloxacin after ERCP developed cholangitis (relative risk = 0.71; 95% CI = 0.14-3.65; p = 0.88). Bacterobilia was found in 27 (56.3%) out of 48 patients. E. coli and Streptococcus viridans were the most common organisms.

CONCLUSION: Continual use of ciprofloxacin in patients with cholestasis after adequate biliary drainage procedures plays no role in reducing cholangitis.

Endotoxin tolerance in human intrahepatic biliary epithelial cells is induced by upregulation of IRAK-M

BACKGROUND/AIM

Biliary epithelial cells possess an innate immune system consisting of Toll-like receptors (TLRs). Although the human bile contains lipopolysaccharide (LPS) in normal as well as diseased livers, LPS physiologically does not elicit an inflammatory response in the biliary tree. This absence of a response to LPS could be due to the 'endotoxin tolerance' speculated to maintain innate immune homeostasis in organs. Our aim here is to clarify the presence and molecular mechanisms of endotoxin tolerance of biliary epithelium.

METHODS AND RESULTS

In nuclear factor-kappaB (NF-kappaB)-DNA binding assays using three-cultured human intrahepatic biliary epithelial cell (HIBEC) lines, all the cells responded to LPS (TLR4 ligand) by activating NF-kappaB, but pretreatment with LPS for 24 h effectively induced tolerance against any subsequent stimulation with LPS (endotoxin tolerance). This tolerance was also induced by pretreatment with Pam(3)Cys-Ser-(Lys)(4) trihydrochloride (Pam(3)CKS(4), TLR1/2 ligand). Then, real-time polymerase chain treaction and Western blotting revealed that LPS treatment upregulated the expression of IRAK-M (a negative regulator of TLR signaling), but did not affect interleukin-1 receptor-associated kinase-1 (IRAK-1, an essential molecule of TLR signaling), in HIBECs. Moreover, immunohistochemistry revealed that IRAK-M was diffusely expressed in intrahepatic bile ducts.

CONCLUSIONS

This study showed that the mechanism of endotoxin tolerance exists in the intrahepatic biliary tree and is possibly induced by the expression of IRAK-M in the intrahepatic biliary epithelium, suggesting that the endotoxin tolerance is important in maintaining innate immune biliary homeostasis.

Hepatolithiasis after hepatic portoenterostomy for biliary atresia

BACKGROUND

Hepatolithiasis after hepatic portoenterostomy for biliary atresia has been paid little attention, with only 22 reported cases.

PATIENTS AND METHODS

Fifteen patients underwent living-related liver transplantation for biliary atresia after hepatic portoenterostomy in our hospital between 1998 and 2004. The resected livers were examined for the existence and location of hepatolithiasis, composition of the calculi, and bacterial infection of bile. The relation between a history of cholangitis and the presence of hepatolithiasis was analyzed.

RESULTS

Intrahepatic calculi were found in 8 (53%) of 15 patients. The calculi consisted of almost 100% calcium bilirubinate. Calculi were found in bile lakes in 8 patients. Bacteria were present in the bile in 8 (53%) of the 15 patients. Of the 8 patients, 7 (88%) had a history of ascending cholangitis.

CONCLUSIONS

Hepatolithiasis occurs after hepatic portoenterostomy for biliary atresia more frequently than previously thought. Bile stasis and possibly bile infection are the main causes of calculi formation.

Bile infection contributes to intrahepatic calculi formation after excision of choledochal cysts

Intrahepatic calculi complicate choledochal cysts in 7-8% of patients. Although congenital stenoses and dilatation of the intrahepatic bile ducts are considered responsible for calculi formation, intrahepatic calculi are usually formed after cyst excision. In this study, bile specimens from patients with choledochal cysts were cultured for bacteria. Results were retrospectively analyzed among the following groups: the primary excision group, consisting of 97 patients undergoing cyst excision as a primary treatment (mean age 5.0 years), the internal drainage group, consisting of 13 patients who had previous cyst-enterostomy at cyst excision (mean age 20.2 years); and the hepatolithiasis group, consisting of 12 patients with postoperative hepatolithiasis (mean age 24.2 years). Bacteria were present in the bile of 10 patients (76.9%) in the internal drainage group and in all patients (100%) in the hepatolithiasis group, but present in only 17 patients (17.5%) in the primary excision group (p<0.01). Polymicrobial infection with Gram-negative enterobacteria such as Escherichia coli and Klebsiella species was predominant in the internal drainage and hepatolithiasis groups, while nonenteric bacteria were found in the primary excision group. Bile infection through bilioenterostomy may play an important role in intrahepatic calculus formation after excision of a choledochal cyst.

Peptide antibiotic human beta-defensin-1 and -2 contribute to antimicrobial defense of the intrahepatic biliary tree

Human beta-defensins (hBDs) are important antimicrobial peptides that contribute to innate immunity at mucosal surfaces. This study was undertaken to investigate the expression of hBD-1 and hBD-2 in intrahepatic biliary epithelial cells in specimens of human liver, and 4 cultured cell lines (2 consisting of biliary epithelial cells and 2 cholangiocarcinoma cells). In addition, hBD-1 and hBD-2 were assayed in specimens of bile. hBD-1 was nonspecifically expressed immunohistochemically in intrahepatic biliary epithelium and hepatocytes in all patients studied, but expression of hBD-2 was restricted to large intrahepatic bile ducts in 8 of 10 patients with extrahepatic biliary obstruction (EBO), 7 of 11 with hepatolithiasis, 1 of 6 with primary biliary cirrhosis (PBC), 1 of 5 with primary sclerosing cholangitis (PSC), 0 of 6 with chronic hepatitis C (CH-C), and 0 of 11 with normal hepatic histology. hBD-2 expression was evident in bile ducts exhibiting active inflammation. Serum C reactive protein levels correlated with biliary epithelial expression of hBD-2. Real-time PCR revealed that in all of 28 specimens of fresh liver, including specimens from patients with hepatolithiasis, PBC, PSC, CH-C and normal hepatic histology, hBD-1 messenger RNA was consistently expressed, whereas hBD-2 messenger RNA was selectively expressed in biliary epithelium of patients with hepatolithiasis. Immunobloting analysis revealed hBD-2 protein in bile in 1 of 3 patients with PSC, 1 of 3 with PBC, and each of 6 with hepatolithiasis; in contrast, hBD-1 was detectable in all bile samples examined. Four cultured biliary epithelial cell lines consistently expressed hBD-1; in contrast these cell lines did not express hBD-2 spontaneously but were induced to express hBD-2 by treatment with Eschericia coli, lipopolysaccharide, interleukin-1beta or tumor necrosis factor-alpha. In conclusion, these findings suggest that in the intrahepatic biliary tree, hBD-2 is expressed in response to local infection and/or active inflammation, whereas hBD-1 may constitute a preexisting component of the biliary antimicrobial defense system.

Antibiotic prophylaxis in interventional radiology

Despite several decades of advances in both minimally invasive techniques and antibiotic therapy, infection remains one of the more common complications of invasive procedures. Interventional radiology (IR) has traditionally been believed to be associated with lower infection rates than surgery. However, new interventional techniques, as well as more aggressive therapeutic interventions, have presented new challenges in relation to pharmacological management of postprocedural infection and pain. The risk of infection associated with IR procedures can never be completely eliminated, and the reasons for this are manifold, including more virulent organisms, ongoing and newly emerging antibiotic resistance, increased numbers of immunocompromised patients, and the adoption into everyday interventional practice of more aggressive interventional techniques such as chemoembolization, uterine fibroid embolization, and complex biliary intervention. Despite the widespread use of prophylactic antibiotics in IR, and the widely held belief that they are beneficial and are the standard of care, randomized controlled clinical trials have never validated the use of antibiotics in this setting. As such, an argument could be made not to use antibiotics at all for prophylaxis in IR. The purpose of this article is to discuss some of the issues relating to the use of prophylactic antibiotics, and what choice of antibiotics physicians make when they decide to use prophylaxis for IR procedures.

The frequency of live bacteria in gallstones

BACKGROUND

Septic complications reported from stones and concretions lost in the peritoneal cavity following laparoscopic cholecystectomy reflect the infective potential of gallstones. Although bacteria have been demonstrated in the core of gallstones by scanning electron microscopy and molecular genetic techniques, gallstone culture is the only conclusive proof of whether such bacteria are viable and can cause infection.

METHODS

Gallstones retrieved from patients undergoing cholecystectomy were decontaminated after surface cleaning with alcohol, and each core was scooped for culture.

RESULTS

In this study organisms were cultured from the cores of gallstones in 81% of cases of cholelithiasis and 77% of cases of gallbladder carcinoma, irrespective of stone type and size. Both enteric (57.5%) and non-enteric (20%) organisms were isolated in cholelithiasis, whereas only enteric bacteria could be cultured from cases of gallbladder carcinoma. Long thought to be a causative agent, Salmonella organisms were detected in none of the 14 cases of gallbladder carcinoma.

CONCLUSION

Contrary to the popular belief that bacteria inside gallstones are dead, gallstones from most patients contain live bacteria with the potential to cause infective complications.

Clinical findings among 62 Thais with cholangiocarcinoma

Cholangiocarcinoma, a malignancy of the biliary duct system, tends to grow slowly and to infiltrate the walls of the ducts, dissecting along tissue planes and leading to biliary tract obstruction. In a retrospective case review, 62 cases diagnosed with cholangiocarcinoma between January 1997 and December 2001 at the King Chulalongkorn Memorial Hospital in Bangkok were studied. The most commonly observed clinical symptoms and signs were fever (96.8%), abdominal pain (87.1%) and malaise or weakness (83.9%). Fifty-one of the 62 tumours detected were distal extrahepatic (82.3%), seven perihilar (11.3%) and four intrahepatic (6.7%). There was a significant increase in serum bilirubin and marked elevation of serum alkaline phosphatase. Almost half (45.2%) of the patients presented with other pathological conditions, mostly cholangitis (19 cases) resulting from acute biliary tract obstruction and ascites (13 cases). The pathogens detected were similar in cases of cholangitis alone and cholangiocarcinoma. The major risk factor for this cancer in Thailand is believed to be exposure to liver fluke in insufficiently cooked traditional foods. As it is still endemic in Thailand, continuous prevention and surveillance of this public health problem are necessary.

Lipopolysaccharide induces overexpression of MUC2 and MUC5AC in cultured biliary epithelial cells: possible key phenomenon of hepatolithiasis

Bacterial infection, bile stasis, mucin hypersecretion, and an alteration of the mucin profile such as an aberrant expression of gel-forming apomucin (MUC2 and MUC5AC) in the intrahepatic biliary tree are thought to be important in the lithogenesis of hepatolithiasis. So far, there have been no detailed studies linking bacterial infection to altered mucus secretion of biliary epithelium. In this study, the influence of lipopolysaccharide (LPS), a bacterial component, on apomucin expression in cultured murine biliary epithelial cells was examined with emphasis on the participation of tumor necrosis factor (TNF)-alpha. It was found that LPS up-regulated the expression of MUC2 and MUC5AC in cultured murine biliary epithelial cells. LPS also induced the expression of TNF-alpha in biliary epithelial cells and its secretion into the culture medium. The up-regulation of these apomucins was inhibited by pretreatment with TNF-alpha antibody. TNF-alpha alone also induced the overexpression of MUC2 and MUC5AC in cultured biliary epithelial cells. This overexpression was inhibited by pretreatment with calphostin C, an inhibitor of protein kinase C. These findings suggest that LPS can induce overexpression of MUC2 and MUC5AC in biliary epithelial cells via synthesis of TNF-alpha and activation of protein kinase C. This mechanism might be involved in the lithogenesis of hepatolithiasis.