Detection ofHelicobacter pyloriDNA in peripheral blood from patients with peptic ulcer or gastritis

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

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

Stochastic processes govern bacterial communities from the blood of pikas and from their arthropod vectors

Vector-borne microbes influence pathogen transmission and blood microbiomes, thereby affecting the emergence of infectious diseases. Thus, understanding the relationship between host and vector microbiomes is of importance. In this study, we investigated the bacterial community composition, diversity and assembly of the flea (Rhadinopsylla dahurica vicina), torsalo (Hypoderma curzonial), and the blood and gut of their shared pika host, Ochotona curzoniae. Bartonella, Sphingomonas and Bradyrhizobium were enriched in blood, while Wolbachia and Fusobacterium were more abundant in fleas and torsaloes. Most of potential pathogenic microbes (belonging to Fusobacterium, Rickettsia, Kingella, Porphyromonas, Bartonella and Mycoplasma) were present in the blood of pikas and their vectors. Blood communities were more similar to those from fleas than other sample types and were independent of host factors or geographical sites. Notably, blood microbes originate mainly from fleas rather than gut or torsaloes. Interestingly, the community assembly of blood, fleas or torsaloes was primarily governed by stochastic processes, while the gut microbiome was determined by deterministic processes. Ecological drift plays a dominant role in the assembly of blood and flea microbiomes. These results reflect the difficulty for predicting and regulating the microbial ecology of fleas for the prevention of potential microbiome-associated diseases.

Coinfection with Helicobacter pylori and Opisthorchis viverrini Enhances the Severity of Hepatobiliary Abnormalities in Hamsters

Persistent infection with Opisthorchis viverrini causes hepatobiliary abnormalities, predisposing infected individuals to cholangiocarcinoma (CCA). In addition, Helicobacter pylori is highly prevalent in most countries and is a possible risk factor for CCA; however, its role in enhancing hepatobiliary abnormality is unclear. Here, we investigated the effects of coinfection with H. pylori and O. viverrini on hepatobiliary abnormality. Hamsters were divided into four groups: (i) normal, (ii) H. pylori infected (HP), (iii) O. viverrini infected (OV), and (iv) O. viverrini and H. pylori infected (OV+HP). At 6 months postinfection, PCR and immunohistochemistry were used to test for the presence of H. pylori in the stomach, gallbladder, and liver. In the liver, H. pylori was detected in the following order: OV+HP, 5 of 8 (62.5%); HP, 2 of 5 (40%); OV, 2 of 8 (25%). H. pylori was not detected in normal (control) liver tissues. Coinfection induced the most severe hepatobiliary abnormalities, including periductal fibrosis, cholangitis, and bile duct hyperplasia, leading to a significantly decreased survival rate of experimental animals. The greatest thickness of periductal fibrosis was associated with a significant increase in fibrogenesis markers (expression of alpha smooth muscle actin and transforming growth factor beta). Quantitative reverse transcription-PCR revealed that the highest expression levels of genes for proinflammatory cytokines (interleukin-1 [IL-1], IL-6, and tumor necrosis factor alpha) were also observed in the OV+HP group. These results suggest that coinfection with H. pylori and O. viverrini increased the severity of hepatobiliary abnormalities to a greater extent than either single infection did.

Helicobacter pylori Bacteremia: An Unusual Finding

We report a case of Helicobacter pylori transient bacteremia in a woman with ulcerated antral gastric cancer. The patient was hospitalized for laparoscopy and subtotal gastrectomy. After surgery she developed fever (39°C) and was empirically treated with levofloxacin. Blood cultures, collected and sent immediately to Laboratory, were positive for a spiral Gramnegative bacterium. This isolate was identified as H. pylori and the specific susceptibility test was performed. One day after the fever was decreased but antibiotic treatment with levofloxacin was continued and it was maintained until discharge. In summary, H. pylori transient bacteremia may occur as a rare complication after stomach surgery. Further studies are necessary to elucidate the potential role of H. pylori presence in blood.

The dormant blood microbiome in chronic, inflammatory diseases

Blood in healthy organisms is seen as a ‘sterile’ environment: it lacks proliferating microbes. Dormant or not-immediately-culturable forms are not absent, however, as intracellular dormancy is well established. We highlight here that a great many pathogens can survive in blood and inside erythrocytes. ‘Non-culturability’, reflected by discrepancies between plate counts and total counts, is commonplace in environmental microbiology. It is overcome by improved culturing methods, and we asked how common this would be in blood. A number of recent, sequence-based and ultramicroscopic studies have uncovered an authentic blood microbiome in a number of non-communicable diseases. The chief origin of these microbes is the gut microbiome (especially when it shifts composition to a pathogenic state, known as ‘dysbiosis’). Another source is microbes translocated from the oral cavity. ‘Dysbiosis’ is also used to describe translocation of cells into blood or other tissues. To avoid ambiguity, we here use the term ‘atopobiosis’ for microbes that appear in places other than their normal location. Atopobiosis may contribute to the dynamics of a variety of inflammatory diseases. Overall, it seems that many more chronic, non-communicable, inflammatory diseases may have a microbial component than are presently considered, and may be treatable using bactericidal antibiotics or vaccines.

Atopobiosis of microbes (the term describing microbes that appear in places other than where they should be), as well as the products of their metabolism, seems to correlate with, and may contribute to, the dynamics of a variety of inflammatory diseases.

Diverse bacteria promote macrophage foam cell formation via Toll-like receptor-dependent lipid body biosynthesis

AIM

Atherosclerotic lesions contain DNA signatures from a wide variety of bacteria, although little is known of how exposure to these organisms may modulate the accumulation of lipids in macrophages.

METHODS

To address this, a panel of nine bacteria representing those most frequently reported to be present in human atheroma were examined for their potential to promote lipid accumulation in human primary monocytes and murine J774 macrophages.

RESULTS

All bacteria examined, and defined stimulants of Toll-like receptors (TLRs) 2, 3, 4, 5 and 9, induced lipid body formation and cholesterol ester accumulation in a dose-dependent manner. The mechanisms of bacteria-mediated foam cell formation were found to be dependent on TLR2 and/or TLR4 signalling, but independent of lipoprotein oxidation pathways, since lipid accumulation was significantly inhibited by the TLR4 inhibitors polymyxin-B and TAK-242, or the TLR2 and TLR4 inhibitor oxidised palmitoyl-arachidonyl-phosphatidyl-choline, but not by the scavenger receptor blocker polyinosinic acid or the antioxidant butylated hydroxytoluene. A number of genes involved in lipid body biosynthesis, including perilipin-A, stearoyl-coenzyme-A desaturase 1, fatty acid synthase and HMG-CoA reductase were upregulated in response to TLR4 stimulation.

CONCLUSIONS

The bacterial debris observed in human atheroma, which is currently considered to be harmless, may have potential to contribute to disease progression via TLR-dependent lipid body formation in macrophages.

Helicobacter Pylori DNA in Liver Tissues From Chronic Hepatitis C Egyptian Patients

Background

Hepatitis C virus (HCV) is considered the most common etiology of chronic liver disease in Egypt, which may progress to cirrhosis and hepatocellular carcinoma (HCC). Previous studies have documented an association between Helicobacter pylori (H. pylori) infection and liver cirrhosis with or without HCC. This study aimed to investigate the presence of H. pylori DNA in the liver tissue of Egyptian patients with chronic hepatitis C (CHC).

Methods

Fifty-two CHC Egyptian patients were enrolled in this study. Plasma anti-H. pylori IgG was assessed with ELISA. Liver biopsies were tested for presence of Helicobacter DNA using genus specific nested polymerase chain reaction (PCR) and species was identified by sequencing.

Results

Anti-H. pylori IgG was detected in 31/52 (59.6%) CHC patients while Helicobacter DNA was detected in 6 (11.5%) patients, all were H. Pylori by sequencing. Helicobacter DNA was more frequent in patients with high stage liver fibrosis (33.3%) than in those with low stage fibrosis (2.7%) (P = 0.006). There was no association between the presence of H. pylori DNA in the liver and age, gender of patients, liver function tests, AFP levels or viral load.

Conclusions

These data confirm the presence of H. pylori DNA in liver of some CHC Egyptian patients and suggest an association of this bacterium with progression of liver fibrosis.

The pathological effect of Helicobacter pylori infection on liver tissues in mice

Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. Some reports also suggest that it causes extragastric disease, including hepatitis. In this study, the pathological changes in the liver and gall bladder in H. pylori-colonized C57BL/6 mice were investigated. Twenty mice were inoculated orally with H. pylori strain SS1, and ten controls were injected with phosphate-buffered saline. Gastric colonization with H. pylori was assessed at 2 months after inoculation. Mice were examined at 8 months by histopathology, culture for H. pylori, and PCR for specific H. pylori genes. All C57BL/6 mice infected with H. pylori for 8 months developed severe gastric mucosal inflammation. Three mice showed mild-to-moderate multifocal hepatitis. The gall bladder mucosa of one H. pylori-infected mouse showed thickening of the mucous membrane with mild submucosal lymphocytic infiltration. H. pylori was observed morphologically in four liver specimens and six gall bladders from infected mice by immunohistochemistry. Specific H. pylori genes were also detected in six liver samples from infected mice, six samples of bile, and two blood samples by nested PCR. Thus, H. pylori inoculated orally may reach the hepatobiliary system and cause inflammation as an independent aetiological factor. The pathway to the liver may be via the blood or the biliary system.

Procuration and identification of bacteria in paraffin-embedded liver tissues of hepatocellular carcinoma by laser-assisted microdissection technique

This study was aimed at procuring directly and identifying the bacteria which had been found in paraffin-embedded liver tissues of hepatocellular carcinoma (HCC) patients. In our previous studies, Helicobacter spp. had been detected by polymerase chain reaction (PCR) and observed by histology in the liver tissues of HCC patients but had never been cultured successfully. To obtain and identify the uncultured bacteria, laser microdissection and pressure catapulting (LMPC) techniques were applied. Following microdissection from the liver tissue sections, these bacteria were examined by PCR using Helicobacter genus-specific 16S rRNA primers and sequence analysis. Amplified products of 16S rRNA were positive in all six microdissected samples with bacteria, and showed 99%-100% similarity with Helicobacter pylori by sequence analysis. Another H. pylori-specific 26 kDa gene (encoding one 26 kDa protein as H. pylori-specific antigen) was also tested by PCR. Four of six samples were positive. Therefore, Helicobacter spp. detected by PCR in the liver tissues of HCC patients in our previous studies are actually the bacteria observed by histology and identified as H. pylori by further sequence analysis. The laser-assisted microdissection technique can be extensively applied for identification of bacteria in tissue samples in bacteriology research.