Invasive Non-Typhoidal Salmonella Lineage Biofilm Formation and Gallbladder Colonization Vary But Do Not Correlate Directly with Known Biofilm-Related Mutations

Non-typhoidal Salmonella (NTS) serovars have a broad host range and cause gastroenteritis in humans. However, invasive NTS (iNTS) bloodstream infections have increased in the last decade, causing 60,000 deaths annually. Human-specific typhoidal Salmonella colonizes and forms biofilms on gallstones, resulting in chronic, asymptomatic infection. iNTS lineages are undergoing genomic reduction and may have adapted to person-to-person transmission via mutations in virulence, bile resistance, and biofilm formation. As such, we sought to determine the capacity of iNTS lineages for biofilm formation and the development of chronic infections in the gallbladder in our mouse model. Of the lineages tested (L1, L2, L3 and UK), only L2 and UK were defective for the rough, dry and red (RDAR) morphotype, correlating with the known bcsG (cellulose) mutation but not with csgD (curli) gene mutations. Biofilm-forming ability was assessed in vitro, which revealed a biofilm formation hierarchy of L3 > ST19 > UK > L1 = L2, which did not correlate directly with either the bcsG or the csgD mutation. By confocal microscopy, biofilms of L2 and UK had significantly less curli and cellulose, while L1 biofilms had significantly lower cellulose. All iNTS strains were able to colonize the mouse gallbladder, liver, and spleen in a similar manner, while L3 had a significantly higher bacterial load in the gallbladder and increased lethality. While there was iNTS lineage variability in biofilm formation, gallbladder colonization, and virulence in a chronic mouse model, all tested lineages were capable of colonization despite possessing biofilm-related mutations. Thus, iNTS strains may be unrecognized chronic pathogens in endemic settings.

Genomic characterization of Salmonella enterica serovar Choleraesuis from Brazil reveals a swine gallbladder isolate harboring colistin resistance gene mcr-1.1

Salmonella enterica serovar Choleraesuis (S. Choleraesuis) is a swine-adapted serovar associated to invasive infections in humans. In Brazil, data of strains of this serovar are scarce. In the present study, six S. Choleraesuis strains of animal (n = 5) and human (n = 1) origin from Brazil were screened for phenotypic antimicrobial resistance using disk-diffusion assay and using whole-genome sequencing data to search for antimicrobial resistance genes, plasmids, prophages, and Salmonella pathogenicity islands (SPIs). Its genetic relatedness was evaluated by MLST and SNP analysis. A single isolate from swine gallbladder harbored the colistin resistance gene mcr-1.1 into a IncX4 plasmid. In the six strains analyzed, resistance was found to tetracycline, nalidixic acid, ciprofloxacin, ampicillin, piperacillin, streptomycin, cefazoline, gentamycin, sulfamethoxazole-trimethoprim, and choloramphenicol, along with resistance genes aac(6')-Iaa, aac(3)-IV, aph(3'')-Ib, aph(6)-Id, aph(4)-Ia, aadA1, aph(3')-IIa, blaTEM-1A, floR, sul1, sul2, tet(B), drfA1, erm(B), mph(B), lnu(G), qacE, and gyrA point mutation Serine83 → Tyrosine and parC Threonine57 → Serine. Furthermore, IncF and IncH plasmids, ten SPIs, and seven prophage types were detected. All strains were assigned to ST145 and five belonged to a common SNP cluster of S. Choleraesuis strains from Brazil. The presence of S. Choleraesuis isolated from animals harboring relevant antimicrobial resistance profiles and virulence determinants reinforced the urge for enhanced surveillance to avoid its transmission to humans through food items.

Association of Microbial Dysbiosis with Gallbladder Diseases Identified by Bile Microbiome Profiling

BACKGROUND

Cholecystitis is an important risk factor for gallbladder cancer, but the bile microbiome and its association with gallbladder disease has not been investigated fully. We aimed to analyze the bile microbiome in normal conditions, chronic cholecystitis, and gallbladder cancer, and to identify candidate bacteria that play an important role in gallbladder carcinogenesis.

METHODS

We performed metagenome sequencing on bile samples of 10 healthy individuals, 10 patients with chronic cholecystitis, and 5 patients with gallbladder cancer, and compared the clinical, radiological, and pathological characteristics of the participants.

RESULTS

No significant bacterial signal was identified in the normal bile. The predominant dysbiotic bacteria in both chronic cholecystitis and gallbladder cancer were those belonging to the Enterobacteriaceae family. Klebsiella increased significantly in the order of normal, chronic cholecystitis, and gallbladder cancer. Patients with chronic cholecystitis and dysbiotic microbiome patterns had larger gallstones and showed marked epithelial atypia, which are considered as precancerous conditions.

CONCLUSION

We investigated the bile microbiome in normal, chronic cholecystitis, and gallbladder cancer. We suggest possible roles of Enterobacteriaceae, including Klebsiella, in gallbladder carcinogenesis. Our findings reveal a possible link between a dysbiotic bile microbiome and the development of chronic calculous cholecystitis and gallbladder cancer.

Biliary microbiota and mucin 4 impact the calcification of cholesterol gallstones

BACKGROUND

Cholesterol gallstones account for over 80% of gallstones, and the pathogenesis of gallstone formation involves genetic and environmental factors. However, data on the evolution of cholesterol gallstones with various densities are limited. This study aimed to determine the roles of microbiota and mucins on the formation of calcified cholesterol gallstones in patients with cholelithiasis.

METHODS

Paired gallbladder tissues and bile specimens were obtained from cholelithiasis patients who were categorized into the isodense group and calcified group according to the density of gallstones. The relative abundance of microbiota in gallbladder tissues was detected. Immunohistochemistry and enzyme-linked immunosorbent assay were performed to detect the expression levels of MUC1, MUC2, MUC3a, MUC3b, MUC4, MUC5ac and MUC5b in gallbladder tissues and bile. The correlation of microbiota abundance with MUC4 expression was evaluated by linear regression.

RESULTS

A total of 23 patients with gallbladder stones were included. The density of gallstones in the isodense group was significantly lower than that of the calcified group (34.20 ± 1.50 vs. 109.40 ± 3.84 HU, P < 0.0001). Compared to the isodense group, the calcified group showed a higher abundance of gram-positive bacteria at the fundus, in the body and neck of gallbladder tissues. The concentrations of MUC1, MUC2, MUC3a, MUC3b, MUC5ac and MUC5b in the epithelial cells of gallbladder tissues showed no difference between the two groups, while the concentrations of MUC4 were significantly higher in the calcified group than that in the isodense group at the fundus (15.49 ± 0.69 vs. 10.23 ± 0.54 ng/mL, P < 0.05), in the body (14.54 ± 0.94 vs. 11.87 ± 0.85 ng/mL, P < 0.05) as well as in the neck (14.77 ± 1.04 vs. 10.85 ± 0.72 ng/mL, P < 0.05) of gallbladder tissues. Moreover, the abundance of bacteria was positively correlated with the expression of MUC4 (r = 0.569, P < 0.05) in the calcified group.

CONCLUSIONS

This study showed the potential clinical relevance among biliary microbiota, mucins and calcified gallstones in patients with gallstones. Gram-positive microbiota and MUC4 may be positively associated with the calcification of cholesterol gallstones.

A dual-therapy approach for the treatment of biofilm-mediated Salmonella gallbladder carriage

Asymptomatic carriage of Salmonella Typhi continues to facilitate the transmission of typhoid fever, resulting in 14 million new infections and 136,000 fatalities each year. Asymptomatic chronic carriage of S. Typhi is facilitated by the formation of biofilms on gallstones that protect the bacteria from environmental insults and immune system clearance. Here, we identified two unique small molecules capable of both inhibiting Salmonella biofilm growth and disrupting pre-formed biofilm structures without affecting bacterial viability. In a mouse model of chronic gallbladder Salmonella carriage, treatment with either compound reduced bacterial burden in the gallbladder by 1–2 logs resulting in bacterial dissemination to peripheral organs that was associated with increased mortality. Co-administration of either compound with ciprofloxacin not only enhanced compound efficacy in the gallbladder by a further 1–1.5 logs for a total of 3–4.5 log reduction, but also prevented bacterial dissemination to peripheral organs. These data suggest a dual-therapy approach targeting both biofilm and planktonic populations can be further developed as a safe and efficient treatment of biofilm-mediated chronic S. Typhi infections.

Typhoid fever is an infectious disease caused by Salmonella Typhi (S. Typhi), a bacterium that causes as many as 14 million new infections and 136,000 deaths annually. Asymptomatic chronic carriers of S. Typhi play a major role in the transmission of typhoid fever, as they intermittently shed the bacteria and can unknowingly infect surrounding individuals. Here, we characterized novel compounds that target biofilm formation, a process utilized by S. Typhi to establish and maintain chronic carriage in the gallbladder, in hopes that they may be eventually used in conjunction with traditional antibiotics to prevent and/or cure chronic infections more efficiently than antibiotics alone.

Acalculous cholecystitis with gallbladder necrosis in a patient presenting without abdominal pain

An 83-year-old man with a history of chronic myelogenous leukaemia in remission maintained with bosutinib presented with new-onset fevers. He denied pain and had no other focal symptoms. Ultrasound imaging revealed mild gallbladder wall thickening. Non-contrasted CT revealed right upper quadrant inflammation of indeterminate source. The diagnosis of acalculous cholecystitis was made on the third day when a CT with oral contrast demonstrated a remarkably inflamed biliary tree. The gallbladder was surgically removed and found to be necrotic. The case highlights an unusual presentation for a well-known condition. Both ultrasound and CT have limited diagnostic sensitivity for acalculous cystitis. This case adds to existing literature to support development of acalculous cholecystitis in non-critically ill patients. Clinicians should maintain awareness of this condition among patients presenting to the hospital or clinic with abdominal pain. Careful discussion with radiology and surgery is indicated to guide diagnostic testing when initial imaging results are indeterminate.

Comparison of endoscopic naso-gallbladder drainage and percutaneous transhepatic gallbladder drainage in acute suppurative cholecystitis: Study Protocol Clinical Trial (SPIRIT Compliant)

INTRODUCTION

Transitional drainage, which is followed by cholecystectomy plays a key role in the management of acute cholecystitis, especially in high-risk surgical patients. Endoscopic naso-gallbladder drainage (ENGBD) is an alternative to percutaneous transhepatic gallbladder drainage (PTGBD) for patients who need temporary drainage. There is a lack of prospective comparison on the relevant outcomes of the two drainage methods during the period of drainage, especially the subsequent cholecystectomy.

METHODS

This is a randomized controlled two-arm non-blind single center trial. Patients with acute cholecystitis undergo emergent or early cholecystectomy and need drainage will be randomly assigned to group PTGBD or ENGBD. Pain score is defined as the primary endpoint, whereas several secondary endpoints, such as the rates of technical success, clinical remission, open conversion of cholecystectomy will be determined to elucidate more detailed differences between two groups. The general feasibility, safety, and quality checks required for high-quality evidence will be adhered to.

DISCUSSION

This study would provide the first type A evidence concerning the comparison of ENGBD versus PTGBD in surgically high-risk patients with acute cholecystitis, it will be the first trial designed to determine the impact of two drainage methods on not only peri-drainage but also peri-LC.

TRIAL REGISTRATION

NCT03701464. Registered on October 10, 2018.

Systemic infection facilitates transmission of Pseudomonas aeruginosa in mice

Health care-associated infections such as Pseudomonas aeruginosa bacteremia pose a major clinical risk for hospitalized patients. However, these systemic infections are presumed to be a "dead-end" for P. aeruginosa and to have no impact on transmission. Here, we use a mouse infection model to show that P. aeruginosa can spread from the bloodstream to the gallbladder, where it replicates to extremely high numbers. Bacteria in the gallbladder can then seed the intestines and feces, leading to transmission to uninfected cage-mate mice. Our work shows that the gallbladder is crucial for spread of P. aeruginosa from the bloodstream to the feces during bacteremia, a process that promotes transmission in this experimental system. Further research is needed to test to what extent these findings are relevant to infections in patients.

The human gallbladder microbiome is related to the physiological state and the biliary metabolic profile

BACKGROUND

The microbial populations of the human intestinal tract and their relationship to specific diseases have been extensively studied during the last decade. However, the characterization of the human bile microbiota as a whole has been hampered by difficulties in accessing biological samples and the lack of adequate methodologies to assess molecular studies. Although a few reports have described the biliary microbiota in some hepatobiliary diseases, the bile microbiota of healthy individuals has not been described. With this in mind, the goal of the present study was to generate fundamental knowledge on the composition and activity of the human bile microbiota, as well as establishing its potential relationship with human bile-related disorders.

RESULTS

Human bile samples from the gallbladder of individuals from a control group, without any record of hepatobiliary disorder, were obtained from liver donors during liver transplantation surgery. A bile DNA extraction method was optimized together with a quantitative PCR (qPCR) assay for determining the bacterial load. This allows the selection of samples to perform functional metagenomic analysis. Bile samples from the gallbladder of individuals suffering from lithiasis were collected during gallbladder resection and the microbial profiles assessed, using a 16S rRNA gene-based sequencing analysis, and compared with those of the control group. Additionally, the metabolic profile of the samples was analyzed by nuclear magnetic resonance (NMR). We detected, for the first time, bacterial communities in gallbladder samples of individuals without any hepatobiliary pathology. In the biliary microecosystem, the main bacterial phyla were represented by Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. Significant differences in the relative abundance of different taxa of both groups were found. Sequences belonging to the family Propionibacteriaceae were more abundant in bile samples from control subjects; meanwhile, in patients with cholelithiasis members of the families Bacteroidaceae, Prevotellaceae, Porphyromonadaceae, and Veillonellaceae were more frequently detected. Furthermore, the metabolomics analysis showed that the two study groups have different metabolic profiles.

CONCLUSIONS

Our results indicate that the gallbladder of human individuals, without diagnosed hepatobiliary pathology, harbors a microbial ecosystem that is described for the first time in this study. Its bacterial representatives and metabolites are different from those detected in people suffering from cholelithiasis. In this regard, since liver donors have been subjected to the specific conditions of the hospital's intensive care unit, including an antibiotic treatment, we must be cautious in stating that their bile samples contain a physiologically normal biliary microbiome. In any case, our results open up new possibilities to discover bacterial functions in a microbial ecosystem that has not previously been explored.

Diet: Cause or Consequence of the Microbial Profile of Cholelithiasis Disease?

Recent dietary habits and lifestyle could explain the shaping of the gut microbiota composition and, in consequence, the increasing prevalence of certain pathologies. However, little attention has been paid to the influence of diet on microbiotas, other than the gut microbiota. This is important in cholelithiasis, given that changes in the production of bile acids may affect gallbladder microbial communities. Our aim was to assess the association between regular dietary intake and gallbladder microbial composition. Fourteen adults with cholelithiasis and 14 controls, sex‒age-matched and without gastrointestinal pathology, were included. Diet was assessed through a food frequency questionnaire and quantification of gallbladder microbiota sequences by Illumina 16S rRNA gene-based analysis. The cholelithiasic patients showed greater intake of potatoes and lower consumption of vegetables, non-alcoholic drinks, and sauces, which resulted in a lower intake of energy, lipids, digestible polysaccharides, folate, calcium, magnesium, vitamin C, and some phenolic compounds. Regarding the altered bile microorganisms in cholelithiasic patients, dairy product intake was negatively associated with the proportions of Bacteroidaceae and Bacteroides, and several types of fiber, phenolics, and fatty acids were linked to the abundance of Bacteroidaceae, Chitinophagaceae, Propionibacteraceae, Bacteroides, and Escherichia‒Shigella. These results support a link between diet, biliary microbiota, and cholelithiasis.

Diagnostic metabolite biomarkers of chronic typhoid carriage

Background

Salmonella Typhi and Salmonella Paratyphi A are the agents of enteric (typhoid) fever; both can establish chronic carriage in the gallbladder. Chronic Salmonella carriers are typically asymptomatic, intermittently shedding bacteria in the feces, and contributing to disease transmission. Detecting chronic carriers is of public health relevance in areas where enteric fever is endemic, but there are no routinely used methods for prospectively identifying those carrying Salmonella in their gallbladder.

Methodology/Principal findings

Here we aimed to identify biomarkers of Salmonella carriage using metabolite profiling. We performed metabolite profiling on plasma from Nepali patients undergoing cholecystectomy with confirmed S. Typhi or S. Paratyphi A gallbladder carriage (and non-carriage controls) using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) and supervised pattern recognition modeling. We were able to significantly discriminate Salmonella carriage samples from non-carriage control samples. We were also able to detect differential signatures between S. Typhi and S. Paratyphi A carriers. We additionally compared carriage metabolite profiles with profiles generated during acute infection; these data revealed substantial heterogeneity between metabolites associated with acute enteric fever and chronic carriage. Lastly, we found that Salmonella carriers could be significantly distinguished from non-carriage controls using only five metabolites, indicating the potential of these metabolites as diagnostic markers for detecting chronic Salmonella carriers.

Conclusions/Significance

Our novel approach has highlighted the potential of using metabolomics to search for diagnostic markers of chronic Salmonella carriage. We suggest further epidemiological investigations of these potential biomarkers in alternative endemic enteric fever settings.

Enteric fever, caused by typhoidal Salmonella serovars, remains a substantial public health problem in many low- and middle-income countries. The human-restricted nature of these organisms combined with the development of new vaccines suggests that regional elimination of enteric fever should be possible. However, individuals that chronically carry Salmonella in their gallbladder, such as the notorious Typhoid Mary, complicates enteric fever transmission and maintain circulation of the organisms. The prospective detection of chronic Salmonella carriers is therefore a critical step for regional enteric fever elimination. However, there are currently no diagnostic methods routinely in use for this purpose. Here, we used a novel method for identifying chronic Salmonella carriers by comparing metabolite patterns in plasma samples from patients with chronic Salmonella carriage against non-carriage controls. We could significantly distinguish Salmonella carriers from non-carriers based on a large set of metabolites. Five metabolites were then highlighted, after comparing metabolite patterns obtained during chronic Salmonella carriage and acute enteric fever respectively, which could significantly distinguish Salmonella carriers from non-carriers. These potential biomarkers require further evaluation in epidemiological investigations of enteric fever in alternative endemic settings but this study provides a first step towards improved detection of Salmonella carriers.

Tuberculosis of Gallbladder Mimicking Carcinoma

Gallbladder is a rare site of tuberculous involvement. Less than 150 cases have been documented in the last 150 years. It may mimic malignancy. Histopathology examination is the mainstay of diagnosis. Gallstones and obstruction appear to be pre-disposing factors. Treatment involves localizing other sites and starting patient on anti-tuberculosis therapy. The report describes this rare site of involvement in an adult Pakistani man.

Tuberculosis of Gal-Blader Mimicking Malignancy - A Case Report

A correct preoperative diagnosis of gall-bladder tuberculosis is exceptionally unusual in the absence of pathognomic features both on clinical presentation and on imaging. Herein we present a case of 50 year female who was operated with a provisional diagnosis of gall-bladder malignancy and was found to have tuberculosis of gall-bladder on histopathology.

An 86-year-old man with acute abdominal pain

An 86-year-old man presented with severe pain in the upper abdomen along with fever. On physical examination, we found an arterial blood pressure of 84/43 mm Hg, a heart rate of 80 bpm and a temperature of 38.3°C. The abdomen was painful and peristalsis was absent. Empiric antibiotic therapy for sepsis was started with amoxicillin/clavulanate and gentamicin. CT scan of the abdomen revealed an emphysematous cholecystitis. Percutaneous ultrasound-guided cholecystostomy was applied. Bile cultures revealed Clostridium perfringens. Emphysematous cholecystitis is a life-threatening form of acute cholecystitis that occurs as a consequence of ischaemic injury to the gallbladder, followed by translocation of gas-forming bacteria (ie, C. perfringens, Escherichia coli, Klebsiella and Streptococci). The mortality associated with emphysematous cholecystitis is higher than in non-emphysematous cholecystitis (15% vs 4%). Therefore, early diagnosis with radiological imaging is of vital importance.

Characterization of the Invasive, Multidrug Resistant Non-typhoidal Salmonella Strain D23580 in a Murine Model of Infection

A distinct pathovar of Salmonella enterica serovar Typhimurium, ST313, has emerged in sub-Saharan Africa as a major cause of fatal bacteremia in young children and HIV-infected adults. D23580, a multidrug resistant clinical isolate of ST313, was previously shown to have undergone genome reduction in a manner that resembles that of the more human-restricted pathogen, Salmonella enterica serovar Typhi. It has since been shown through tissue distribution studies that D23580 is able to establish an invasive infection in chickens. However, it remains unclear whether ST313 can cause lethal disease in a non-human host following a natural course of infection. Herein we report that D23580 causes lethal and invasive disease in a murine model of infection following peroral challenge. The LD₅₀ of D23580 in female BALB/c mice was 4.7 x 10⁵ CFU. Tissue distribution studies performed 3 and 5 days post-infection confirmed that D23580 was able to more rapidly colonize the spleen, mesenteric lymph nodes and gall bladder in mice when compared to the well-characterized S. Typhimurium strain SL1344. D23580 exhibited enhanced resistance to acid stress relative to SL1344, which may lend towards increased capability to survive passage through the gastrointestinal tract as well as during its intracellular lifecycle. Interestingly, D23580 also displayed higher swimming motility relative to SL1344, S. Typhi strain Ty2, and the ST313 strain A130. Biochemical tests revealed that D23580 shares many similar metabolic features with SL1344, with several notable differences in the Voges-Proskauer and catalase tests, as well alterations in melibiose, and inositol utilization. These results represent the first full duration infection study using an ST313 strain following the entire natural course of disease progression, and serve as a benchmark for ongoing and future studies into the pathogenesis of D23580.

A deadly form of non-typhoidal Salmonella has emerged as a major cause of invasive disease in sub-Saharan Africa. Initial genomic profiling of this novel Salmonella sequence type, ST313, indicated that although it is technically classified as S. Typhimurium (a serovar characterized by a broad host range), it may be evolving towards becoming a more human-specific, ‘typhoid-like’ pathogen. However, it was recently demonstrated that ST313 strains were indeed able to establish an invasive and damaging infection in chickens. Despite these important findings, it remains unclear whether ST313 is able to cause lethal disease in a non-human host, since no study has yet followed the entire natural course of disease progression. As such, there are no data available concerning the median lethal dose (LD₅₀) of any ST313 strain. This is an important metric, as the LD₅₀ value will serve as a benchmark for mechanistic studies focused on understanding the relationship between virulence and the phenotypic and molecular genetic attributes associated with ST313 infections. Here we report that D23580 causes lethal disease in BALB/c mice and determined the LD₅₀ following peroral challenge. Phenotypic characterization revealed distinct differences in tissue distribution, acid stress resistance, and biochemical utilization between D23580 and the ‘classic’ Typhimurium strain SL1344.

[DISSEMINATION BY H. PYLORI IN PATIENTS, SUFFERING VARIOUS FORMS OF CHOLECYSTITIS]

Comparative analysis of dissemination by H. pylori of the bile portions in patients of a control group, suffering an acute calculous cholecystitis (ACCH), was performed. Dissemination of H. pylori in a control group was significantly less, than in a bile portions of patients, suffering ACCH. While analyzing the rate and degree of dissemination by H. pylori of the gastic and gallbladder mucosa biopsies of patients, suffering chronic non-calculous cholecystitis, associated with duodenogastric reflux and gastroduodenitis, bacteria were revealed trustworthy more often and in more number, than in a gallbladder mucosa in patients, suffering ACCH.

Isolation and Antimicrobial Testing of Aeromonas spp., Citrobacter spp., Cronobacter spp., Enterobacter spp., Escherichia spp., Klebsiella spp., and Trabulsiella spp. from the Gallbladder of Pigs

The presence of Gram-negative bacteria species, other than Salmonella spp., in the gallbladder of pigs was examined. Isolated Gram-negative bacteria were assigned to species using the Microgen™ GnA+B-ID Systems. Of the 64 isolated strains 43 were identified as Escherichia coli, seven as Enterobacter spp., three each as Klebsiella spp., Citrobacterfreundii, Aeromonas hydrophila and Cronobacter sakazakii and one each as Escherichiafergusonii and Trabulsiella guamensis. Their antibiograms showed very high resistance to ampicillin, amoxicillin, tetracycline, chloramphenicol and sulfamethoxazole/trimethoprim. It was concluded that the pigs' gallbladder is a reservoir of potentially pathogenic Gram-negative bacteria for pork consumers.

Histopathological analysis of Salmonella chronic carriage in the mouse hepatopancreatobiliary system

Salmonella Typhi asymptomatic chronic carriage represents a challenge for the diagnosis and prevention of typhoid fever in endemic areas. Such carriers are thought to be reservoirs for further spread of the disease. Gallbladder carriage has been demonstrated to be mediated by biofilm formation on gallstones and by intracellular persistence in the gallbladder epithelium of mice. In addition, both gallstones and chronic carriage have been associated with chronic inflammation and the development of gallbladder carcinoma. However, the pathogenic relationship between typhoid carriage and the development of pre-malignant and/or malignant lesions in the hepatopancreatobiliary system as well as the host-pathogen interactions occurring during chronic carriage remains unclear. In this study, we monitored the histopathological features of chronic carriage up to 1 year post-infection. Chronic cholecystitis and hepatitis ranging from mild to severe were present in infected mice regardless of the presence of gallstones. Biliary epithelial hyperplasia was observed more commonly in the gallbladder of mice with gallstones (uninfected or infected). However, pre-malignant lesions, atypical hyperplasia and metaplasia of the gallbladder and exocrine pancreas, respectively, were only associated with chronic Salmonella carriage. This study has implications regarding the role of Salmonella chronic infection and inflammation in the development of pre-malignant lesions in the epithelium of the gallbladder and pancreas that could lead to oncogenesis.

Emphysematous cholecystitis with massive gas in the abdominal cavity

Emphysematous cholecystitis is a rare variant of acute cholecystitis with a high mortality rate. The combination of emphysematous cholecystitis and pneumoperitoneum is also rare. We herein describe a case of emphysematous cholecystitis with massive gas in the abdominal cavity. A 77-year-old male presented with epigastric pain and lassitude lasting for one week. A computed tomography scan demonstrated massive gas in the abdominal cavity. Gas was also detectable inside the gallbladder. Massive ascites as well as a pleural effusion were also detected. Under the diagnosis of perforation of the digestive tract, we performed emergency surgery. Beyond our expectations, the perforation site was not in the alimentary tract, but rather in the gallbladder. We then diagnosed the patient with emphysematous cholecystitis with perforation, and performed cholecystectomy. A pathological examination of the resected gallbladder revealed necrosis in the mucosa and thinning of the wall. Cultures of the ascites detected Clostridium perfringens, a gas-producing microorganism.

The microbiological and clinical characteristics of invasive salmonella in gallbladders from cholecystectomy patients in kathmandu, Nepal

Gallbladder carriage of invasive Salmonella is considered fundamental in sustaining typhoid fever transmission. Bile and tissue was obtained from 1,377 individuals undergoing cholecystectomy in Kathmandu to investigate the prevalence, characteristics and relevance of invasive Salmonella in the gallbladder in an endemic area. Twenty percent of bile samples contained a Gram-negative organism, with Salmonella Typhi and Salmonella Paratyphi A isolated from 24 and 22 individuals, respectively. Gallbladders that contained Salmonella were more likely to show evidence of acute inflammation with extensive neutrophil infiltrate than those without Salmonella, corresponding with higher neutrophil and lower lymphocyte counts in the blood of Salmonella positive individuals. Antimicrobial resistance in the invasive Salmonella isolates was limited, indicating that gallbladder colonization is unlikely to be driven by antimicrobial resistance. The overall role of invasive Salmonella carriage in the gallbladder is not understood; here we show that 3.5% of individuals undergoing cholecystectomy in this setting have a high concentration of antimicrobial sensitive, invasive Salmonella in their bile. We predict that such individuals will become increasingly important if current transmission mechanisms are disturbed; prospectively identifying these individuals is, therefore, paramount for rapid local and regional elimination.

Tuberculosis of the gall bladder clinically mimicking carcinoma--a case report

Gall bladder tuberculosis is very rare and curable but, sometimes can be confused with the clinical diagnosis like carcinoma. A 32-year-old male presented with acute pain in right abdomen for one month and fever off and on for two months. CT scan (whole abdomen) showed features suggestive of lymphadenopathy although peroperatively no significant lymph node could be identified but there were multiple white patches on gastrohepatic ligament and neck of gall bladder probably which were identified as lymph nodes on scanning. On the basis of peroperative findings clinician diagnosed it as a case of carcinoma gall bladder and was subjected to cholecystectomy. On histopathological examination it turned out to be tuberculosis gall bladder. Therefore tuberculosis of gall bladder can mimic carcinoma clinically.

Multi-locus variable-number tandem repeat profiling of Salmonella enterica serovar Typhi isolates from blood cultures and gallbladder specimens from Makassar, South-Sulawesi, Indonesia

Multi-locus variable-number tandem repeat analysis differentiated 297 Salmonella enterica serovar Typhi blood culture isolates from Makassar in 76 genotypes and a single unique S. Typhi genotype was isolated from the cholecystectomy specimens of four patients with cholelithiasis. The high diversity in S. Typhi genotypes circulating in Makassar indicates that the number of carriers could be very large, which may complicate disease prevention and control.

[Histopathological study of the presence of Helicobacter pylori-type bacteria in surgical specimens from patients with chronic cholecystitis]

INTRODUCTION

Helicobacter species have recently been found to be associated with some diseases of the biliary tree but this relationship remains unclear and further studies are required. The aim of this study was to determine the presence of H. pylori-type bacteria in patients with a diagnosis of chronic cholecystitis through histopathological study of surgical gallbladder specimens.

MATERIALS AND METHODS

Surgical gallbladder specimens from patients with a diagnosis of chronic cholecystitis were examined histopathologically. The macroscopic characteristics of the specimens were identified. Histopathological slices were stained with hematoxylin-eosin and Giemsa.

RESULTS

Of the 68 patients who underwent cholecystectomy, 56 (81%) were women and 12 (19%) were men. The mean age was 39.56+11.94 years. H. pylori-type bacteria were found in 6%.

CONCLUSIONS

The results of this study do not allow us to conclude that the presence of H. pylori-type bacteria is a major factor in the etiology and/or pathogenesis of chronic cholecystitis. In patients with chronic cholecystitis undergoing cholecystectomy included in the present study, the etiology of the disease may be more closely linked with the presence of gallstones.

Chronic effects of a Salmonella type III secretion effector protein AvrA in vivo

BACKGROUND

Salmonella infection is a common public health problem that can become chronic and increase the risk of inflammatory bowel diseases and cancer. AvrA is a Salmonella bacterial type III secretion effector protein. Increasing evidence demonstrates that AvrA is a multi-functional enzyme with critical roles in inhibiting inflammation, regulating apoptosis, and enhancing proliferation. However, the chronic effects of Salmonella and effector AvrA in vivo are still unknown. Moreover, alive, mutated, non-invasive Salmonella is used as a vector to specifically target cancer cells. However, studies are lacking on chronic infection with non-pathogenic or mutated Salmonella in the host.

METHODS/PRINCIPAL FINDINGS

We infected mice with Salmonella Typhimurium for 27 weeks and investigated the physiological effects as well as the role of AvrA in intestinal inflammation. We found altered body weight, intestinal pathology, and bacterial translocation in spleen, liver, and gallbladder in chronically Salmonella-infected mice. Moreover, AvrA suppressed intestinal inflammation and inhibited the secretion of cytokines IL-12, IFN-gamma, and TNF-alpha. AvrA expression in Salmonella enhanced its invasion ability. Liver abscess and Salmonella translocation in the gallbladder were observed and may be associated with AvrA expression in Salmonella.

CONCLUSION/SIGNIFICANCE

We created a mouse model with persistent Salmonella infection in vivo. Our study further emphasizes the importance of the Salmonella effector protein AvrA in intestinal inflammation, bacterial translocation, and chronic infection in vivo.

Does Salmonella Typhi primarily reside in the liver of chronic typhoid carriers?

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Does Helicobacter pylori identification in the mucosa of the gallbladder correlate with cholesterol gallstone formation?

OBJECTIVE

Helicobacter pylori (H pylori) represents a potential initiator of cholesterol crystallization and it has been proposed that it is related to gallstone formation. In this study, any possible association between the H pylori identification in the mucosa of gallbladder and cholesterol gallstone formation was evaluated

METHODS

Gallbladders containing pure or mixed cholesterol gallstones (cholelithiasis group, n = 89) and gallbladders without gallstones (control group, n = 42) were submitted to standard histopathological examination for H pylori detection, as well as to nested polymerase chain reaction amplification for H pylori DNA detection.

RESULTS

Helicobacter pylori was identified in the gallbladder's epithelium in four patients with cholelithiasis and in two patients in the control group by histology. In all the cases which were found to be H pylori positive by histological examination, H pylori DNA were also detected. No correlation between gallstone formation and H pylori detection in the biliary epithelium was found. A higher incidence of acute inflammation in the cholelithiasis (22.5% vs 9.5%, p = not significant [ns]) and in the H pylori positive groups (33% vs 17.6%, p = ns) were histologically detected. A higher incidence (10% vs 0%), p = ns) of H pylori in gallbladders with gallstones and acute inflammation, compared to gallbladders with acute inflammation but without gallstones, was noticed

CONCLUSION

Helicobacter pylori is detectable in low frequency in the mucosa of the gallbladder and it does not seem to act as a lithogenic component for cholesterol gallstone formation. Its higher incidence in gallbladders with gallstones and acute inflammation, suggests a possible accessory role in a subset of patients with cholelithiasis.

[Cholecystitis as a complication of typhoid fever]

The problems of chronic infection, pertaining to typhoid fever, with main complication as an acute and chronic cholecystitis, were addressed. The main method of chronic cholecystitis treatment, pertaining to typhoid fever, is cholecystectomy with consequent speciphic treatment using various routes of the drug introduction.

Bioluminescence imaging to evaluate infections and host response in vivo

The continued prospect of emerging pathogens and recent events including the acceptance of widespread drug resistance and threats of bioterrorism have introduced the necessity be creative in our development of therapies for bacterial infections. Many pathogens have both acute and persistent phases. There is a need to understand these pathogens throughout their entire life cycle within the host and determine the role that the host response including innate immunity plays in the establishment and maintenance of the infection. Contag et al. first suggested in 1995 that a novel whole animal, non-invasive imaging modality may provide more data from which to draw conclusions about infectious disease progression and pathogenicity in the context of a living animal. Here are presented methods for imaging two animal models that represent advances in both following the progression of infectious disease in the host and the response of the host to the pathogen.

The culture site of the gallbladder affects recovery of bacteria in symptomatic cholelithiasis

AIM

Traditional methods for bile culturing may miss a large number of underlying bacterial infections that could lead to acute or chronic cholecystitis.

AIM

to evaluate possible differences regarding the site of material collection and thus to detect the most suitable sample site for gallbladder culture.

METHODS

A cohort of 137 patients with symptomatic cholelithiasis was enrolled. After surgical excision of the gallbladder, bile cultures were separately performed from fundus, body and neck. Identification of bacteria as well as computation of mean bacterial concentrations were performed with standard microbiological techniques. Wilcoxon's paired and Chi-square tests were used for comparison between continuous and discrete parameters, respectively.

RESULTS

Thirty-one patients (22.6%) demonstrated at least one positive culture sample. Positivity was 31/31 (100.0%) in neck samples, 20/31 (64.5%) in body and 13/31 (41.9%) in fundus samples (P<0.001). The microorganisms identified were Escherichia coli (14 cases) and Enterococcus faecalis (10 cases), followed by Staphylococcus aureus (3 cases), Pseudomonas aeruginosa, Enterococcus faecium, Enterobacter aerogenes and Enterobacter cloacae (1 case each). Mean bacterial concentrations in positive samples derived from the neck (272.2 +/- 187.5) were higher (P<0.01) when compared to those derived from both the body (38.2 +/- 28.7) and the fundus (12.5 +/- 11.3). Mean bacterial concentrations in positive samples derived from the body were higher (P<0.01) than those derived from the fundus.

CONCLUSION

The neck of the gallbladder hosts the biggest bacterial load in comparison with the body and the fundus. This difference might be attributed to the presence of Rokitansky-Aschoff sinuses, which is the main histological characteristic of the region.

Acute calculous cholecystitis caused by Candida lusitaniae: an unusual causative organism in a patient without underlying malignancy

Candidiasis of the gallbladder is an uncommon cause of acute cholecystitis. Candidal cholecystitis is seen especially in patients with malignancies. In the present case, we report that acute calculous cholecystitis was caused by Candida lusitaniae in a 33-year-old patient without underlying malignancy. According to our review of the literature, this is the first report of acute cholecystitis caused by C. lusitaniae.

Helicobacter pylori in areas of gastric metaplasia in the gallbladder and isolation of H. pylori DNA from gallstones

AIMS

To assess if the areas of gastric metaplasia in the gallbladder are colonised by Helicobacter pylori and to conduct a molecular study of gallstones for presence of H. pylori DNA.

METHODS

Sections from 111 gallbladders with evidence of gastric metaplasia on H&E and Alcian blue-periodic acid-Schiff (pH 2.5) stain were stained with Loeffler's methylene blue and Warthin Starry stain for demonstration of H. pylori. Presence of H. pylori was confirmed by immunohistochemistry. Formalin fixed mucosal tissues and gallstones from 11 cases showing heavy colonisation were subjected to molecular analysis.

RESULTS

Helicobacter pylori was present in 50 of 111 (45%) sections with gastric metaplasia. Areas adjacent to gastric metaplasia in gallbladder showed acute inflammation (6%) and lymphoid follicle formation in 58% of cases with H. pylori that were significantly higher than those seen in sections without H. pylori. In molecular study, 8 of 11 gallstones showed 16S rDNA. Amplification of material from one stone showed positivity for atpA, efp, mutY, ppa, trpC, UreI and vacA genes. Phylogenetic affiliation study of the isolates indicated that H. pylori sequence from the gallstones clustered with Indian strains of H. pylori. No considerable difference was observed in phylogenetic affiliations of eight stones studied.

CONCLUSION

H. pylori colonises areas of gastric metaplasia in gallbladder producing histological changes similar to those seen in gastric mucosa. Isolation of H. pylori DNA from gallstones further support its presence in the gallbladder.

A new concept to stimulate mucosal as well as systemic immunity by parenteral vaccination as applied to the development of a live attenuated Salmonella enterica serovar Dublin vaccine

A new concept of slow "drip feeding" that enables activation of mucosal as well as systemic immunity following parenteral vaccination was demonstrated using Salmonella Dublin in a mouse model. The live vaccine candidate, N-RM25, generated from a wild S. Dublin strain utilising metabolic-drift (spontaneous chromosomal) mutations had a unique sensitivity to bile and restricted growth in the presence of a very low concentration of bile salts No. 3 (0.075% (w/v)) but also had the ability to survive in a high concentration (19.2%) of the substance. Following intraperitoneal administration with 10(7) cfu, N-RM25 colonised and survived (10(1)-10(3) cfu/g) in the liver and spleen of mice for over 24 days without causing disease. A small number of the mutant organisms also penetrated the gall bladder and gut, most likely via the enterohepatic circulation. N-RM25 induced significant levels of serum IgG, IgA and intestinal secretory IgA. A second metabolic-drift mutant (R-NM29) that was rapidly eliminated from the liver and spleen and highly unlikely to penetrate the gall bladder and gut, stimulated some systemic immunity, but induced no mucosal immunity because it did not reach the immune stimulation sites within the gut. In vaccine trials, N-RM25 was significantly more effective in eliminating the homologous challenge bacteria (S. Dublin wild strain FD436) from the internal organs and intestinal lumen when compared to R-NM29 and the negative control. N-RM25 prevented the development of systemic infection and produced 100% protection.

Bacterial culture results from liver, gallbladder, or bile in 248 dogs and cats evaluated for hepatobiliary disease: 1998-2003

BACKGROUND

Information is lacking on the prevalence and susceptibility patterns of bacterial isolates in dogs and cats with suspected hepatobiliary disease.

OBJECTIVES

To characterize the prevalence, identity, and antimicrobial susceptibility of common hepatobiliary isolates from such patients.

ANIMALS

Dogs and cats presented to the University of Wisconsin-Madison Veterinary Medical Teaching Hospital for which samples of bile, gallbladder, or liver were submitted for culture from 1998 to 2003, including 190 dogs (192 culture episodes) and 58 cats (61 culture episodes).

METHODS

Cases were identified from the microbiology laboratory database. Data from patient medical records were extracted, including the history of antimicrobial administration, the presence of fever, the results of CBC and serum biochemistry, the presence of biliary obstruction or hepatobiliary inflammation, and the results of aerobic and anaerobic bacterial cultures and aerobic antimicrobial susceptibilities.

RESULTS

Biliary cultures yielded a significantly higher percentage of positive results overall (30% [18 of 60]) than did hepatic cultures (7% [15 of 215]). In patients with cholecystitis, 62% (8 of 13) had positive biliary cultures. In patients with hepatic inflammation, 23% (7 of 30) had positive bile cultures, whereas only 6% (6 of 103) had positive hepatic cultures. Escherichia coli, Enterococcus spp., Bacteroides spp., Streptococcus spp., and Clostridium spp. were the most common true-positive isolates. More than 80% of Enterobacteriaceae were susceptible to ciprofloxacin or aminoglycosides, with only 30-67% susceptible to first-generation aminopenicillins and cephalosporins. Liver samples obtained by surgery or laparoscopy were more likely to yield positive cultures than those obtained by percutaneous needle biopsy.

H pylori exist in the gallbladder mucosa of patients with chronic cholecystitis

AIM: To study whether H pylori locate in the gallbladder mucosa of patients with chronic cholecystitis.

METHODS: Using Warthy-Starry (W-S) silver stain and immunohistochemistry stain with anti-H pylori antibodies, we screened paraffin specimens in 524 cases of cholecystitis. H pylori urease gene A (HPUA) and H pylori urease gene B (HPUB) were analyzed by polymerase chain reaction (PCR) in the fresh tissue specimens from 81 cases of cholecystitis.

RESULTS: H pylori-like bacteria were found in 13.55% of the gallbladders of the cholecystitis patients using W-S stain. Meanwhile, bacteria positive for H pylori antibodies were also found in 7.1% of the gallbladders of patients with cholecystitis by immunohistochemistry. Of 81 gallbladders, 11 were positive for both HPUA and HPUB, 4 were positive for HPUA only and 7 were positive for HPUB only.

CONCLUSION: H pylori exist in the gallbladders of patients with chronic cholecystitis.

H pylori are associated with chronic cholecystitis

AIM: To study whether H pylori are associated with chronic cholecystitis.

METHODS: The subjects were divided into three groups: H pylori-infected cholecystitis group, H pylori-negative cholecystitis group and control group. Pathologic changes of the gallbladder were observed by optic and electronic microscopes and the levels of interleukin-1, 6 and 8 (IL-1, 6 and 8) were detected by radioimmunoassay.

RESULTS: Histological evidence of chronic cholecystitis including degeneration, necrosis, inflammatory cell infiltration, were found in the region where H pylori colonized. Levels of IL-1, 6 and 8 in gallbladder mucosa homogenates were significantly higher in H pylori-infected cholecystitis group than those in H pylori-negative cholecystitis group and control group.

CONCLUSION: H pylori infection may be related to cholecystitis.

Antimicrobial therapy for acute cholecystitis: Tokyo Guidelines

Acute cholecystitis consists of various morbid conditions, ranging from mild cases that are relieved by the oral administration of antimicrobial drugs or that resolve even without antimicrobials to severe cases complicated by biliary peritonitis. Microbial cultures should be performed by collecting bile at all available opportunities to identify both aerobic and anaerobic organisms. Empirically selected antimicrobials should be administered. Antimicrobial activity against potential causative organisms, the severity of the cholecystitis, the patient’s past history of antimicrobial therapy, and local susceptibility patterns (antibiogram) must be taken into consideration in the choice of antimicrobial drugs. In mild cases which closely mimic biliary colic, the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) is recommended to prevent the progression of inflammation (recommendation grade A). When causative organisms are identified, the antimicrobial drug should be changed for a narrower-spectrum antimicrobial agent on the basis of the species and their susceptibility testing results.

Prevalence of Escherichia coli O157:H7 in gallbladders of beef cattle

Gallbladders and rectal contents were collected from cattle (n=933) at slaughter to determine whether the gallbladder harbors Escherichia coli O157:H7. Both gallbladder mucosal swabs and homogenized mucosal tissues were used for isolation. Only five gallbladders (0.54%) were positive for E. coli O157:H7. Fecal prevalence averaged 7.1%; however, none of the cattle that had E. coli O157:H7 in the gallbladder was positive for E. coli O157:H7 in feces. Therefore, the gallbladder does not appear to be a common site of colonization for E. coli O157:H7 in beef cattle.

Natural presence of Campylobacter spp. in various internal organs of commercial broiler breeder hens

Campylobacter are known to cause acute bacterial gastroenteritis in humans. Poultry products have been implicated as a significant source of these infections. Six experiments were performed to determine whether Campylobacter could be isolated naturally from the primary and secondary lymphoid organs, liver/gallbladder, and ceca of commercial broiler breeder hens. Broiler breeder hens were acquired from different commercial sources during the early, middle, and late lay cycles. The birds were euthanatized, defeathered, and aseptically opened. To reduce the possibility of cross-contamination between samples, the thymus, spleen, and liver/gallbladder were aseptically removed prior to removal of the ceca. Individual samples were placed in sterile bags, packed on ice, and transported to the laboratory for evaluation. In this study Campylobacter were found in 11 of 43 thymii, eight of 43 spleens, four of 43 liver/gallbladders, and 30 of 43 ceca. Overall, 28 of 53 isolates from the above samples were Campylobacter coli and 25 of 53 isolates were found to be Campylobacter jejuni.

Isolation of Escherichia coli O157:H7 from the gall bladder of inoculated and naturally-infected cattle

To determine if Escherichia coli O157:H7 is capable of residing in the gall bladder of cattle, inoculation studies were conducted with O157:H7 strain 86-24 in weaned Holstein calves. Strain 86-24 was isolated from the gall bladders of five calves 36 days after inoculation. Two other calves contained the inoculation strain in the distal colon but the organism was absent in their gall bladders. A second trial in which the calves were euthanized 15 days after inoculation found strain 86-24 in six of seven inoculated calves but only in colon and/or rumen samples. In a third trial that inoculated eight calves with a four-strain cocktail of O157:H7 strains, the gall bladders from all eight animals were positive 9 days after inoculation. The colon and rumen samples from these calves were also positive. E. coli O157:H7 isolates recovered from bile samples and subtyped by pulsed field gel electrophoresis found that three of the four inoculation strains were present in one or more of the calves. Thus, residence in the gall bladder is not restricted to a single strain. Additional evidence of the ability to localize in the gall bladder of cattle was provided by testing the bile from 150 gall bladders (five collection dates, 30 samples each) obtained at an abbatoir and the isolation of E. coli O157:H7 from four samples (2.7%). This study establishes that E. coli O157:H7 can reside transiently or permanently at a low level in the gall bladder of cattle.

Helicobacter species ribosomal DNA in the pancreas, stomach and duodenum of pancreatic cancer patients

AIM: To determine whether gastric and enteric Helicobacter species are associated with pancreatic cancer.

METHODS: Patients with exocrine pancreatic cancer (n = 40), neuroendocrine cancer (n = 14), multiple endocrine neoplasia type 1 (n = 8), and chronic pancreatitis (n = 5) were studied. Other benign pancreatic diseases (n = 10) and specimens of normal pancreas (n = 7) were included as controls. Pancreatic tissue specimens were analyzed by Helicobacter-specific PCR-assay and products were characterized by denaturing gradient electrophoresis and DNA-sequencing. From a subset of the pancreatic cancer patients, gastric and/or duodenal tissue as well as gallbladder and ductus choledochus tissue were analyzed. Gallbladder and choledochus samples were included as controls. Stomach and duodenum samples were investigated to analyze whether a gastric helicobacter might disseminate to the pancreas in pancreatic cancer patients. Pancreatic specimens were analyzed by Bacteroides-specific PCR for detecting the translocation of indigenous gut microbes to the diseased pancreas.

RESULTS: Helicobacter DNA was detected in pancreas (tumor and/or surrounding tissue) of 75% of patients with exocrine cancer, 57% of patients with neuroendocrine cancer, 38% of patients with multiple endocrine neoplasia, and 60% of patients with chronic pancreatitis. All samples from other benign pancreatic diseases and normal pancreas were negative. Thirty-three percent of the patients were helicobacter-positive in gastroduodenal specimens. Surprisingly, H. bilis was identified in 60% of the positive gastroduodenal samples. All gallbladder and ductus choledochus specimens were negative for helicobacter. Bacteroides PCR-assay was negative for all pancreatic samples.

CONCLUSION: Helicobacter DNA commonly detected in pancreatic cancer suggests a possible role of the emerging pathogens in the development of chronic pancreatitis and pancreatic cancer.

Heterogeneity of Campylobacter jejuni and Campylobacter coli strains from healthy sheep

The objectives of this study were to identify, at species level, thermophilic campylobacters isolated from clinically healthy sheep by a multiplex polymerase chain reaction (mPCR). The heterogeneity among Campylobacter jejuni and C. coli isolates was also investigated using a restriction fragment length polymorphism (RFLP) analysis of the flagellin (flaA) gene. Samples of intestinal contents, gall bladders and faeces were collected from 610 healthy sheep. While gall bladder samples were plated directly onto Preston agar, an enrichment stage was applied for intestinal and faecal samples. Of the 610 samples, 302 (49.5%) were positive for Campylobacter spp. Using a mPCR assay for species identification, 103 (34.1%) were positive with C. jejuni-specific primers, while 100 (33.1%) were positive with C. coli-specific primers. Additionally, 16 (11.9%) of the intestinal content samples were positive for both species by mPCR. All the isolates identified as C. jejuni and C. coli were successfully subtyped by flaA typing. Of 203 isolates tested, 48 different flaA types were found. Twenty-six flaA types were identified among C. jejuni isolates and the remaining 22 from C. coli isolates.

Acute calculous cholecystitis associated with brucellosis: a report of two cases and review of the literature

Acute cholecystitis is a very rare complication of Brucella infections. We report 2 cases of acute cholecystitis due to Brucella and review previously reported cases.

Infection as a risk factor for gallbladder cancer

Gallbladder cancer is a common hepato-biliary malignancy with poor prognosis. The main associated risk factors identified so far include cholelithiasis (especially mixed gall stone), chronic infections of the gallbladder, obesity, reproductive factors, diet, hepato-biliary anamolies, and environmental exposure to specific chemicals. Genetic and molecular predisposing factors have also been described. This article reviews the association of chronic infection and gallbladder cancer. Most of the studies have shown a good association of mixed bacterial and Salmonella infections in the carcinogenesis of cancer gallbladder especially in the area of high endemicity of typhoid. Bacterial degradation of bile and chronic inflammation may also play some role in the carcinogenic process. Mutations in multiple tumor suppressor gene and oncogenes (P53 and K-ras) have also been found in a few studies. This review seeks to bring out many hidden infective etiological aspects of the pathogenesis of gallbladder cancer. Review of the entire published literature suggests a need for further studies for better understanding of the disease.

Helicobacter pylori and cholesterol gallstone formation in C57L/J mice: a prospective study

Recently, we demonstrated that cholesterol gallstone-prone C57L/J mice rarely develop gallstones unless they are infected with certain cholelithogenic enterohepatic Helicobacter species. Because the common gastric pathogen H. pylori has been identified in the hepatobiliary tree of cholesterol gallstone patients, we wanted to ascertain if H. pylori is cholelithogenic, by prospectively studying C57L infected mice fed a lithogenic diet. Weanling, Helicobacter spp.-free male C57L mice were either infected with H. pylori SS1 or sham dosed. Mice were then fed a lithogenic diet (1.0% cholesterol, 0.5% cholic acid, and 15% dairy triglycerides) for 8 wk. At 16 wk of age, mice were euthanatized, the biliary phenotype was analyzed microscopically, and tissues were analyzed histopathologically. H. pylori infection did not promote cholesterol monohydrate crystal formation (20% vs. 10%), sandy stone formation (0% for both), or true gallstone formation (20%) compared with uninfected mice fed the lithogenic diet (10%). Additionally, H. pylori failed to stimulate mucin gel accumulation in the gallbladder or alter gallbladder size compared with uninfected animals. H. pylori-infected C57L mice developed moderate to severe gastritis by 12 wk, and the lithogenic diet itself produced lesions in the forestomach, which were exacerbated by the infection. We conclude that H. pylori infection does not play any role in murine cholesterol gallstone formation. Nonetheless, the C57L mouse develops severe lesions of both the glandular and nonglandular stomach in response to H. pylori infection and the lithogenic diet, respectively.

A prfA transposon mutant of Listeria monocytogenes F2365, a serotype 4b strain, is able to survive in the gastrointestinal tract but does not cause systemic infection of the spleens and livers of intragastrically inoculated mice

prfA is a member of the Crp/Fnr family of global regulatory genes in Listeria monocytogenes that has been shown previously to regulate several key virulence determinants both in vitro and in parenterally inoculated laboratory rodents. However, the role of prfA in the ability of L. monocytogenes to cause infection via the gastrointestinal (GI) tract has not been clearly established. In this study, we used a prfA transposon mutant of L. monocytogenes F2365, a serotype 4b strain, to assess the role of prfA in the pathogenesis of gastrointestinal listeriosis in mice. We found that the prfA mutant was able to survive in the GI tract (i.e., cecum) of mice, albeit in numbers somewhat less than those of the wild-type parent strain of L. monocytogenes. However, mice inoculated with the prfA mutant did not exhibit systemic infection of the spleen and liver, as was noted for mice inoculated with the wild-type parent strain. Survival of the prfA mutant in synthetic gastric fluid at pH 2.5 or 5 was somewhat reduced compared to that of the wild-type strain, as was its ability to invade and multiply within differentiated human intestinal epithelial cells (Caco-2 cells). Prior infection with the prfA mutant gave mice some protection against a subsequent challenge with virulent L. monocytogenes, although much less than that gained by prior gastrointestinal infection with the wild-type parent strain. These findings indicate that the global regulatory gene prfA is dispensable for colonization of the GI tract in mice but not for systemic infection.