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Mitochondria are essential organelles that are not only responsible for energy production but are also involved in cell metabolism, calcium homeostasis, and apoptosis. Targeting mitochondria is a key strategy for bacteria to subvert host cells' physiology and promote infection. Helicobacter (H.) pylori targets mitochondria directly. However, mitochondrial genome (mtDNA) polymorphism (haplogroup) is not yet considered an important factor for H. pylori infection. Here, we clarified the association of mitochondrial haplogroups with H. pylori prevalence and the ability to perform damage. Seven mtDNA haplogroups were identified among 28 H. pylori -positive subjects. Haplogroup B was present at a higher frequency and haplotype D at a lower one in the H. pylori population than in that of the H. pylori -negative one. The fibroblasts carrying high-frequency haplogroup displayed a higher apoptotic rate and diminished mitochondrial respiration following H. pylori infection. mtDNA mutations were accumulated more in the H. pylori -positive population than in that of the H. pylori -negative one in old age. Among the mutations, 57% were located in RNA genes or nonsynonymous protein-coding regions in the H. pylori -positive population, while 35% were in the H. pylori -negative one. We concluded that gastric disease caused by Helicobacter virulence could be associated with haplogroups and mtDNA mutations.

Background and Aims: Isolation of Helicobacter pylori is considered difficult because of the requirement of the additional biopsy tissue and the effort involved in the isolation of the bacterium. We investigated whether H pylori can be cultured from tissue samples used for the rapid urease test (RUT)., Methods: Totally, 174 specimens from 87 patients referred for endoscopy were prospectively included. During endoscopy, two biopsy specimens were obtained, one each from the gastric antrum and the corpus, and were placed into a commercially available RUT kit. After detection of urease activity, H pylori was cultured using tissue leftover in the RUT, regardless of the result., Results: H pylori was successfully isolated using leftover tissue in 72.4% (63/87) of the patients. In 32 patients, H pylori was isolated from both specimens, while in 31 patients, it was isolated from either antrum or corpus. Eighty-one H pylori strains were isolated from 141 specimens with positive RUT results (57.4%), whereas 14 strains were isolated from 33 specimens with negative RUT results (42.4%). The median interval between tissue acquisition and inoculation onto the isolation media was 3.6 hours (range: 0.5-27.5 hours) in cases with successful cultures, compared to 23.5 hours (range: 0.5-76.0 hours) in cases with failed cultures. Among the positive RUT tissues, 80.4% (45/56) were cultured successfully when the tissue was inoculated within 4 hours of the biopsy., Conclusions: RUT kits can be used as transport media for H pylori, and this media is most efficient when used within 4 hours of the test., (© 2020 John Wiley & Sons Ltd.)

Background/aims: The increased resistance of Helicobacter pylori to antibiotics has increased the need to develop new treatments for this bacterium. The aim of our study was to identify new drugs with anti- H. pylori activity., Methods: We screened a small molecule library-the library of pharmacologically active compounds (LOPAC), which includes 1,280 pharmacologically active compounds-to identify inhibitors of H. pylori growth. The minimal inhibitory concentrations (MICs) of antibiotics against multidrug-resistant H. pylori strains were determined using the agar dilution method., Results: We identified diphenyleneiodonium (DPI) as a novel anti- H. pylori agent. The MIC values for DPI were ＜0.03 µg/mL against all tested H. pylori strains. DPI also exhibited strong antibacterial activity against common gram-negative and gram-positive pathogenic bacteria., Conclusions: DPI may be a candidate anti- H. pylori drug for future development.

Background/aims: MicroRNAs (miRNAs) regulate gene expression. We assess miRNA regulation by Helicobacter pylori infection and elucidate their role in H. pylori -infected gastric epithelial cells., Methods: The relationship between miRNA expression and DNA methylation was examined. Cells were treated with the nuclear factor-kappaB (NF-κB) inhibitor Bay 11-7082 to determine the relationship between miRNA expression and NF-κB signal transduction., Results: In the negative control cells infected with H. pylori 26695, the expression of six miRNAs was increased, whereas the expression of five miRNAs was decreased. The expression of upregulated miRNAs was increased when the host cells were treated with H. pylori and an NF-κB inhibitor. miR-127-5p, -155, and -181 were associated with increased interleukin 6 (IL-6) secretion in H. pylori infected cells treated with anti-miRNA. The expression of miR-155, -127-5p, -195, -216, -206, and -488 increased by approximately 3-fold following treatment with the methylation inhibitor Aza., Conclusions: We found novel miRNAs in H. pylori -infected negative control cells using miRNA microarrays. Upregulated miRNA expression was inversely related to the transcription of NF-κB. miR-195 and miR-488 appear to play a pivotal role in controlling IL-6 activity in H. pylori infection. miRNA expression in H. pylori infection was affected by methylation.

Helicobacter pylori (H. pylori) infection induces a chronic inflammatory response, which promotes gastric carcinogenesis. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) plays a key role as a tumor suppressor in gastrointestinal cancers. The aim of this study was to elucidate the role of 15-PGDH in gastric carcinogenesis associated with H. pylori. 15-PGDH expression in gastric biopsies from H. pylori-infected (n = 25) and noninfected (n = 15) subjects was analyzed by quantitative real-time PCR, Western blot analysis, and immunohistochemistry. 15-PGDH DNA methylation was evaluated by methylation-specific PCR and pyrosequencing. The expression of 15-PGDH, Snail, extracellular signal-regulated kinase (ERK)1/2, TLR4, and MyD88 in response to H. pylori infection was assessed by immunoblot analysis. Compared with negative specimens, H. pylori-positive specimens had 2-fold lower 15-PGDH mRNA levels and significantly less 15-PGDH protein. In four H. pylori-infected subjects with longitudinal follow-up, the suppression of 15-PGDH expression was reversed by H. pylori eradication therapy. In parallel with suppressing 15-PGDH expression, H. pylori infection activated expression of TLR4 and MyD88 expression, increased levels of phospho-ERK1/2, and increased expression of EGF receptor (EGFR)-Snail. Inhibition of Snail and MyD88 reversed suppression of 15-PGDH expression, and siMyD88 reduced phosphorylated ERK1/2. Similarly, treatment with an ERK1/2 and EGFR inhibitor also restored 15-PGDH expression. H. pylori appeared to promote gastric carcinogenesis by suppressing 15-PGDH. This process is mediated by the TLR4/MyD88 pathway via ERK1/2 or EGFR-Snail transcriptional regulation. 15-PGDH may be a useful marker and a potential therapeutic target in H. pylori-induced gastric carcinogenesis.

Background and Aim: Increased resistance of Helicobacter pylori to antibiotics has increased the need to develop new first-line treatments for H. pylori. We have prospectively evaluated 10-day sequential versus conventional triple therapy in peptic ulcer patients., Methods: One hundred and fifty-nine patients with peptic ulcer diseases were prospectively randomized to receive 10 days of lansoprazole, amoxicillin, and clarithromycin (conventional triple therapy) or 5 days of lansoprazole and amoxicillin followed by 5 days of lansoprazole, clarithromycin, and metronidazole (sequential therapy). Post-treatment H. pylori status was determined by the (13) C-urea breath test. Eradication rates, antibiotic resistance rates by agar dilution method, drug compliance, and side-effects were compared., Results: The intention-to-treat eradication rates were 75.9% (95% CI 66.5-85.3%, 60/79) in the sequential therapy group and 58.7% (95% CI 47.9-69.5%, 47/80) in the conventional triple therapy group (P = 0.01), while the per-protocol eradication rates were 86.8% (95% CI 78.7-94.8%, 59/68) and 67.6% (95% CI 56.5-78.7%, 46/68) (P = 0.01), respectively. Compliance and side-effects were similar in the two groups. Culture of H. pylori showed that 18.2% were resistant to clarithromycin, 41.9% to metronidazole. Dual resistance to both antibiotics was 9.6%., Conclusions: Although 10-day sequential therapy yielded a higher H. pylori eradication rate than 10-day conventional triple therapy, the sequential therapy protocol did not result in a sufficiently satisfactory eradication rate. This might be related to the higher antibiotics resistance rate especially to dual resistance. More effective regimens are needed to overcome antibiotic resistance in Korea., (© 2012 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Background and Aim: New regimens, including those with new fluoroquinolones, have been developed to overcome the antibiotic resistance of Helicobacter pylori. We aimed to assess the antibiotic resistance rates, as well as the molecular mechanisms of fluoroquinolone resistance, of the clinical isolates obtained in Korea., Methods: The minimal inhibitory concentration (MIC) values of ciprofloxacin, amoxicillin, clarithromycin, metronidazole and tetracycline were determined by the agar dilution method for 185 treatment-naïve Helicobacter pylori isolates. The resistant strains were evaluated for the presence of point mutations in the quinolone resistance-determining region (QRDR) of the gyrA and gyrB genes by direct nucleotide sequencing., Results: Twenty-nine (29/185, 15.7%) of the strains were found to be resistant to ciprofloxacin. The resistance rates to amoxicillin, clarithromycin, metronidazole and tetracycline were 2.2% (four of 185), 10.8% (20 of 185), 30.3% (56 of 185) and 0.5% (one of 185), respectively. The most common mutations in the H. pylori gyrA gene were found at codons corresponding to Asp87 (16/29, 55.2%) and Asn91 (10/29, 34.5%)., Conclusions: Primary H. pylori resistance to ciprofloxacin occurred at a high frequency. The fluoroquinolone resistance is most likely mediated through amino acid point mutation in the gyrA gene at Asn87 and Asp91., (© 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)

A Helicobacter pylori mutant defective in a putative mfd gene was constructed and characterized. The mfd gene is required for DNA repair and is involved in DNA recombination processes. The mfd mutant strain displayed a greatly increased susceptibility to antibiotics, indicating that this gene plays a significant role in the antibiotic resistance of H. pylori strain J99.

Background/Aim. In Korea, the rate of Helicobacter pylori (H. pylori) eradication has declined steadily as a result of increasing resistance to antibiotics, especially dual resistance to clarithromycin and metronidazole. However, microbiological culture data on drug-resistant H. pylori is lacking. This study evaluated the antimicrobial efficacy of candidate antibiotics against resistant H. pylori strains. Methods. After retrospectively reviewing the data from the Helicobacter Registry in Gil Medical Center (GMC) and Asan Medical Center (AMC), along with 4 reference strains, we selected the 31 single- or multidrug-resistant strains. The susceptibility of the H. pylori strains to seven antibiotics (clarithromycin, metronidazole, levofloxacin, amoxicillin, tetracycline, rifabutin, and furazolidone) and minimum inhibitory concentration were tested using the broth microdilution technique. Results. Among 31 antibiotic resistance strains for H. pylori, there were no strains resistant to rifabutin or furazolidone, which had MICs of <0.008 and 0.5 μg/mL, respectively. Only one tetracycline-resistant strain was found (MIC < 2 μg/mL). Amoxicillin and levofloxacin were relatively less effective against the H. pylori strains compared to rifabutin or furazolidone (resistance rates 22.6%, 1.9%, respectively). Tetracycline showed the relatively low resistance rates (3.2%) for H. pylori strains. Conclusions. Therefore, along with tetracycline which has already been used as a component for second-line eradication regimen for Helicobacter, rifabutin and furazolidone, alone or in combination, could be used to eradicate antibiotic-resistant H. pylori strains where drug-resistant Helicobacter spp. are increasing. [ABSTRACT FROM AUTHOR]

Background: Increased prevalence of antibiotic resistance to Helicobacter pylori (H. pylori) infection worldwide has driven the search for a new therapeutic candidate. Recently, sitafloxacin, a novel 4-quinolone agent, has emerged as a new therapeutic option for H. pylori eradication, in Japan. However, data on its efficacy for H. pylori eradication in Korea are limited. Therefore, we aimed to investigate the therapeutic potential of sitafloxacin as a first-line treatment for patients with Helicobacter infection through gastric tissue culture-based studies. Materials and Methods: We prospectively enrolled treatment-naïve patients with H. pylori infection who visited the Gil Medical Center between March 2015 and March 2018. After obtaining written informed consent from patients, a total of 121 H. pylori strains were collected. We tested the susceptibility of these strains to sitafloxacin, and other antibiotics for Helicobacter eradication, including clarithromycin (CLR), metronidazole (MTZ), amoxicillin (AMX), tetracycline (TET), levofloxacin (LEV), and ciprofloxacin (CIP) using the agar dilution technique. The minimum inhibitory concentration (MIC) of these antibiotics against H. pylori strains were determined. Results: None of the H. pylori strains obtained were resistant to sitafloxacin (MIC > 1, n = 0), while other conventional eradication drugs including CLR, MTZ, AMX, and TET showed 24.8% (n = 30), 30.6% (n = 37), 5.0% (n = 6), and 0.8% (n = 1) resistance, respectively. Compared to the resistance rates of other quinolones (LEV [36.4%, n = 44] and CIP [37.2%, n = 45]), sitafloxacin showed the best antibiotic performance against Helicobacter strains (0%, n = 0). Furthermore, sitafloxacin also inhibited the growth of 14 H. pylori strains (12.4%), which were resistant to both of clarithromycin, and metronidazole, and 27 strains (22.3%) with multidrug resistance. Conclusions: Sitafloxacin might be a new promising candidate for Helicobacter eradication where antibiotic resistance for Helicobacter is an emerging medical burden, such as in Korea. [ABSTRACT FROM AUTHOR]

Background: The increasing prevalence of antimicrobial resistance, together with the lack of novel treatment options, negatively affects successful eradication of Helicobacter pylori. The aim of this study was to investigate genetic mutations in the 23S rRNA genes, which is associated with clarithromycin resistance, and to determine the clinical impact of genotype on phenotypic antimicrobial resistance. Methods: A total of 46 H. pylori strains were obtained from 13 patients, before and after unsuccessful eradication with clarithromycin-based triple therapy. The phenotypic resistance of each H. pylori strain was determined by minimum inhibitory concentration against clarithromycin using the serial two-fold agar dilution method. The genomic sequences of 23S rRNA genes were identified through next-generation sequencing, and nucleotide variants were determined based on comparison with genome sequences of the reference strain H. pylori 26695. Results: Clarithromycin resistance was found in 9 of 13 subjects before treatment and all subjects after unsuccessful eradication. Whole-genome sequencing of the 23S rRNA genes detected 42 mutations on 40 nonidentical loci, including 2147A>G (formerly 2143A>G) and 2146A>G (formerly 2142A>G). All strains with clarithromycin-resistant phenotype had either 2147A>G or 2146A>G mutation. When comparing genotype and phenotype for clarithromycin resistance, there was a significant association between 2147A>G mutation and clarithromycin-resistant phenotype. Conclusions: All clarithromycin-resistant strains had either 2146A>G or 2147A>G mutation, suggesting that tests targeting these two mutations may be enough for the prediction of clarithromycin resistance in this population. [ABSTRACT FROM AUTHOR]