Perspectives on methodology for in vitro culture of Helicobacter pylori

Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori-Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria-yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to nutrient concentrations and also were strain-dependent. In conclusion, reduced nutrients stresses H. pylori, promoting its entry into Candida cells. The starvation of both H. pylori and Candida strains reduced the percentages of Y-BLBs, suggesting that starving yeast cells may be less capable of harboring stressed H. pylori cells. Moreover, the endosymbiotic relationship between H. pylori and Candida is dependent on the strains co-cultured.

Validation of a High-Throughput Multiplex Genetic Detection System for Helicobacter pylori Identification, Quantification, Virulence, and Resistance Analysis

Helicobacter pylori (H. pylori) infection is closely related to various gastroduodenal diseases. Virulence factors and bacterial load of H. pylori are associated with clinical outcomes, and drug-resistance severely impacts the clinical efficacy of eradication treatment. Existing detection methods are low-throughput, time-consuming and labor intensive. Therefore, a rapid and high-throughput method is needed for clinical diagnosis, treatment, and monitoring for H. pylori. High-throughput Multiplex Genetic Detection System (HMGS) assay was established to simultaneously detect and analyze a set of genes for H. pylori identification, quantification, virulence, and drug resistance by optimizing the singlet-PCR and multiple primers assay. Twenty-one pairs of chimeric primers consisted of conserved and specific gene sequences of H. pylori tagged with universal sequence at the 5' end were designed. Singlet-PCR assay and multiple primers assay were developed to optimize the HMGS. The specificity of HMGS assay was evaluated using standard H. pylori strains and bacterial controls. Six clinical isolates with known genetic background of target genes were detected to assess the accuracy of HMGS assay. Artificial mixed pathogen DNA templates were used to evaluate the ability to distinguish mixed infections using HMGS assay. Furthermore, gastric biopsy specimens with corresponding isolated strains were used to assess the capability of HMGS assay in detecting biopsy specimens directly. HMGS assay was specific for H. pylori identification. HMGS assay for H. pylori target genes detection were completely consistent with the corresponding genetic background. Mixed infection with different drug-resistant isolates of H. pylori could be distinguished by HMGS assay. HMGS assay could efficiently diagnose H. pylori infection in gastric biopsy specimens directly. HMGS assay is a rapid and high throughput method for the simultaneous identification and quantification of H. pylori, analysis of virulence and drug resistance in both isolated strains and biopsy specimens. It could also be used to distinguish the mixed infection with different resistant genotype strains. Furthermore, HMGS could detect H. pylori infection in gastric biopsy specimens directly.

Direct detection of Helicobacter pylori in biopsy specimens using a high-throughput multiple genetic detection system

AIM

We evaluated the direct high-throughput multiple genetic detection system (dHMGS) for Helicobacter pylori in gastric biopsies.

MATERIALS & METHODS

One hundred and thirty-three specimens were concurrently analyzed by dHMGS, rapid urease test, culture and sequencing.

RESULTS

dHMGS was highly sensitive and specific for H. pylori identification compared with culture and rapid urease test. The correlation coefficient of the quantitative standard curve was R² = 0.983. A significant difference in the relative H. pylori DNA abundance was found in different gastroduodenal diseases. Concordance rates between dHMGS and sequencing for resistance mutations were 97.1, 100.0, 85.3 and 97.1%, respectively. Finally, dHMGS could efficiently distinguish mixed infection in biopsy specimens.

CONCLUSION

The dHMGS could efficiently diagnose and quantify H. pylori burden in biopsies, simultaneously screening for virulence, antibiotic resistance and presence of the multistrain infections.

Draft genome sequence of Janthinobacterium lividum strain MTR reveals its mechanism of capnophilic behavior

Janthinobacterium lividum is a Gram-negative bacterium able to produce violacein, a pigment with antimicrobial and antitumor properties. Janthinobacterium lividum colonizes the skin of some amphibians and confers protection against fungal pathogens. The mechanisms underlying this association are not well understood. In order to identify the advantages for the bacterium to colonize amphibian skin we sequenced Janthinobacterium lividum strain MTR, a strain isolated from Cajón del Maipo, Chile. The strain has capnophilic behavior, with growth favored by high concentrations (5 %) of carbon dioxide. Its genome is 6,535,606 bp in size, with 5,362 coding sequences and a G + C content of 62.37 %. The presence of genes encoding for products that participate in the carbon fixation pathways (dark CAM pathways), and the entire set of genes encoding for the enzymes of the glyoxylate cycle may explain the capnophilic behavior and allow us to propose that the CO2 secreted by the skin of amphibians is the signal molecule that guides colonization by Janthinobacterium lividum.

A Creative Helicobacter pylori Diagnosis Scheme Based on Multiple Genetic Analysis System: Qualification and Quantitation

BACKGROUND

Currently, several diagnostic assays for Helicobacter pylori (H. pylori) are available, but each has some limitations. Further, a high-flux quantitative assay is required to assist clinical diagnosis and monitor the effectiveness of therapy and novel vaccine candidates.

METHODS

Three hundred and eighty-seven adult patients [nonulcer dyspepsia (NUD) 295, peptic ulcer disease (PUD) 77, gastric cancer (GC) 15] were enrolled for gastrointestinal endoscopies. Three biopsy samples from gastric antrum were collected for the following tests: culture, rapid urease test (RUT), histopathology, conventional polymerase chain reaction (PCR), and Multiple Genetic Analysis System (MGAS). The diagnostic capability of H. pylori for all methods was evaluated through the receiver operating characteristic (ROC) curves.

RESULTS

Based on the gold standard, the sensitivity and specificity of MGAS were 92.9 and 92.4%, and positive predict value (PPV) and negative predict value (NPV) were 96.0 and 87.1%, respectively. All the above parameters of MGAS were higher than that of culture (except its specificity), RUT and histopathology, and nearly closed to that of conventional PCR. The area under curve (AUC) was 0.7575 (Culture), 0.8870 (RUT), 0.9000 (Histopathology), 0.9496 (Conventional PCR), and 0.9277 (MGAS). No significant statistical difference was observed for the H. pylori DNA load in different disease groups (p = .067). In contrast, a statistically significant difference in the H. pylori DNA copy number was observed based on age (p = .043) and gender (p = .021).

CONCLUSIONS

The data showed that MGAS performed well in detecting H. pylori infection. Furthermore, the quantitative analysis showed that the load of H. pylori was significantly different within both age and gender groups. These results suggested that MGAS could be a potential alternative method for clinical detection and monitoring of the effectiveness of H. pylori therapy.

Flavonoid Glycosides of Polygonum capitatum Protect against Inflammation Associated with Helicobacter pylori Infection

The antibacterial and anti-inflammatory activities, and protective effects of extracts (flavonoid glycosides) of Polygonum capitatum were investigated to detect the evidence for the utilization of the herb in the clinical therapy of gastritis caused by H. pylori. A mouse gastritis model was established using H. pylori. According to treating methods, model mice were random assigned into a model group (MG group), a triple antibiotics group (TG group, clarithromycin, omeprazole and amoxicillin), low/middle/high concentrations of flavonoid glycosides groups (LF, MF and HF groups) and low/middle/high concentrations of flavonoid glycosides and amoxicillin groups (LFA, MFA and HFA groups). A group with pathogen-free mice was regarded as a control group (CG group). The eradicate rates of H. pylori were 100%, 93%, 89% in TG, MFA and HF groups. The serum levels of IFN-gamma and gastrin were higher in a MG group than those from all other groups (P < 0.05). The serum levels of IFN-gamma and gastrin were reduced significantly in LF, MF and HF groups (P < 0.05) while little changes were observed in LFA, MFA and HFA groups. In contrast, the serum levels of IL-4 were lower and higher in MG and CG groups compared with other groups (P<0.05). The serum levels of IL-4 were increased significantly in LF, MF and HF groups (P < 0.05) while little changes were found in LFA, MFA and HFA groups. According to pathological scores, flavonoid glycosides therapy showed better protection for gastric injuries than the combination of flavonoid glycoside and amoxicillin (P < 0.05). The results suggested that flavonoid glycoside has repairing functions for gastric injuries. The results suggest that the plant can treat gastritis and protect against gastric injuries. The flavonoid glycosides from Polygonum capitatum should be developed as a potential drug for the therapy of gastritis caused by H. pylori.

[Overview of researches for Helicobacter pylori in oral cavity and stomach]

Helicobacter pylori (H. pylori) is one of the most common pathogens in human and it is closely related to gastrointestinal diseases. It is essential for us to understand the transmission process of H. pylori to prevent its spreading. The oral cavity has been proposed as a reservoir for gastric H. pylori, which has been detected by culture and polymerase chain reaction (PCR) in both dental plaque and saliva. Some researchers have proposed H. pylori in oral cavity may play an important role in its transmission and reinfection. Oral-oral or fecal-oral transmission are thought to be the most possible transmit way. This review will discuss the evidence for the role of the oral cavity in the transmission of H. pylori, the difficulties encountered in addressing this topic and possible directions for future research. Oral H. pylori may also play a role in the diagnosis and prevention of deceases related to H. pylori such as gastritis, gastric ulcer and gastric carcinoma. The recent progresses in this area are also reviewed. Moreover, we also discussed the relationship between oral H. pylori and oral deceases like periodontal disease and oral ulcer.

[Overview of researches for Helicobacter pylori in oral cavity and stomach]

Helicobacter pylori (H. pylori) is one of the most common pathogens in human and it is closely related to gastrointestinal diseases. It is essential for us to understand the transmission process of H. pylori to prevent its spreading. The oral cavity has been proposed as a reservoir for gastric H. pylori, which has been detected by culture and polymerase chain reaction (PCR) in both dental plaque and saliva. Some researchers have proposed H. pylori in oral cavity may play an important role in its transmission and reinfection. Oral-oral or fecal-oral transmission are thought to be the most possible transmit way. This review will discuss the evidence for the role of the oral cavity in the transmission of H. pylori, the difficulties encountered in addressing this topic and possible directions for future research. Oral H. pylori may also play a role in the diagnosis and prevention of deceases related to H. pylori such as gastritis, gastric ulcer and gastric carcinoma. The recent progresses in this area are also reviewed. Moreover, we also discussed the relationship between oral H. pylori and oral deceases like periodontal disease and oral ulcer.