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Objective To investigate the resistance of Helicobacter pylori (H. pylori) strains to common antibiotics and to analyze the sites of genetic mutations carried by clarithromycin-resistant strains in order to provide reference for selecting sensitive antibiotics against H. pylori and for providing individualized treatment for patients in Changchun area. Methods Drug resistance of H. pylori clinical isolates to common antibiotics was detected by disk dilution method. The 23S rRNA genes of clarithromycin-resistant strains were amplified by PCR and then sequenced to analyze the presence of mutations. Results In this study, 69 strains of H. pylori were successfully isolated with a positive rate of 23. 1％ . Results of the drug susceptibility test to seven commonly used antibiotics showed that there were 52. 2％ of the isolates resistant to clarithromy-cin, 47. 8％ to tinidazole, 37. 7％ to levofloxacin, 33. 3％ to tetracycline hydrochloride, 30. 4％ to furazoli-done, 30. 4％ to metronidazole and 5. 8％ to amoxicillin. Amoxicillin could continue to be used as a first-line antimicrobial agent. Seven mutation sites were found in the 23S rRNA genes carried by the clarithromy-cin-resistant strains, which were A1821G, G1826A, T1830C, G1940A, A2143G, T2182C and A2223G. The A2143G site mutation accounted for 54. 2％ and was the predominant mutation resulting in the resistance to clarithromycin of H. pylori strains circulating in this area. Conclusions The H. pylori strains isolated from patients with gastroduodenal diseases in Changchun area had a high resistance rate to clarithromycin, which was mainly caused by the A2143G mutation in 23S rRNA gene.
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Background: Due to unrational use of antibiotics in clinical practice, the resistance rate of Helicobacter pylori (Hp) has increased year by year. The drug resistance rate is different in different regions. Aims: To investigate the resistance of Hp to seven commonly used antibiotics in Changchun area, and provide the theoretical guidance for clinical treatment of Hp infection. Methods: The gastric mucosal specimens of 298 patients undergone gastroscopy from Sept. 2014 to Oct. 2017 at the First Hospital of Jilin University were collected. Hp was isolated and identified. The antibiotic sensitivity of Hp was detected by agar dilution method. Results: A total of 69 Hp strains were successfully isolated from 298 gastric mucosal specimens, the isolation rate was 23.1%. The susceptibility test results showed that the resistance rate of clarithromycin was the highest among the 69 strains (52.2%), the lowest was the resistance rate to amoxicillin (5.8%). Seventeen (24.6%) strains were sensitive to the seven antibiotics, 16 (23.2%) strains were resistant to one antibiotic, and 36 (52.2%) strains were resistant to more than two antibiotics. Conclusions: Hp in this region is highly resistant to clarithromycin and nitrooxazoles. Amoxicillin can be recommended as a treatment for eradication of Hp infection.
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Objective To investigate the distribution of cytotoxin-associated gene A (cagA) of Helicobacter pylori (Hp) and the polymorphism of EPIYA motifs in patients with upper gastrointestinal diseases in Changchun area of China and to evaluate the association between EPYIA motifs patterns and gastrointestinal diseases.Methods Hp strains were isolated from clinical samples.Their cagA gene was analyzed by PCR and sequencing analysis.Nucleotide sequence of cagA gene was translated into amino acid sequence by using DNAMAN software,and then the amino acid sequence was imported into software MEGA6.0 for multiple comparisons and construction of a phylogenetic tree.Results A total of 60 Hp strains were isolated and identified from gastric mucosa specimens collected from 298 patients.Hp infection was not correlated with patient's age or sex (P>0.05).The isolation rate of Hp in peptic ulcer disease (PUD) group was higher than that in non-peptic ulcer dyspepsia (NUD) group (P<0.05).Of the 60 Hp strains,90% (54/60) carried cagA gene.Twenty-three out of 26 successfully sequenced strains (88.4%) were East Asian-type including 22 containing EPIYA-ABD motif and one containing EPIYA-ABBD motif.The other three strains (11.6%) were Western type including two carrying EPIYA-ABC motif and one carrying EPIYA-BC motif.Results of the phylogenetic tree showed that the sequences of cagA gene were clustered into two groups,East Asian-type and Western-type groups.East Asian-type strains caused no disease cluster of statistical significance.All Western-type Hp strains were isolated from patients with peptic ulcer disease (PUD).Four mutant Hp strains were detected in the PUD group and the amino acid mutations preferentially occurred in the EPIYA-B segment.Conclusion The positive rate of Hp cagA gene is 90% in this region.Its distribution is not related to the type of gastrointestinal diseases.EPIYA-ABD (84.6%,22/26) is the predominant EPIYA motif.The amino acid mutation of EPIYA-B segment is closely related to peptic ulcer disease.Neither significant change in the sequence of 3' region of Hp cagA gene nor regional difference is observed in those Hp strains circulating in Changchun area of China.
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Background:Ulcerative colitis (UC)is a chronic inflammatory disorder. Studies have shown that intestinal injury of UC is related to changes of tight junction proteins. Aims:To investigate the expressions and localizations of tight junction protein claudin-1,-2,-4. Methods:Forty female Wistar rats were randomly divided into normal control group and model group. Rats in model group received 7. 5 mg/ mL oxazolone enema to induce experimental colitis. Rats received 0. 9%NaCl solution enema were served as normal controls. Macroscopic score and histological score were assessed. ELISA was used to determine serum and colon tissue inflammatory factor TNF-α,IL-4,IL-5,IL-10 levels. Protein expressions of tight junction protein claudin-1,-2,-4 were measured by immunohistochemistry and Western blotting. mRNA expressions of claudin-1,-2,-4 were determined by real-time PCR. Results:Compared with normal control group,macroscopic score and histological score were significantly increased (P < 0. 05),serum and colon tissue IL-4 and IL-5 levels were significantly increased (P < 0. 05)in model group,however,no significant differences in TNF-α and IL-10 levels were found between the two groups (P > 0. 05). mRNA and protein expressions of claudin-1,-4 were significantly decreased in model group than in normal control group (P < 0. 05),while mRNA and protein expressions of claudin-2 were significantly increased (P < 0. 05). Conclusions:Changes of distributions and expressions of tight junction protein claudin-1,-2,-4 are found in experimental colitis rats,which may lead to impaired epithelial barrier,and might be served as potential target for treatment of UC.
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Background:Ulcerative colitis (UC)is a chronic inflammatory disorder. Studies have shown that intestinal injury of UC is related to changes of tight junction proteins. Aims:To investigate the expressions and localizations of tight junction protein claudin-1,-2,-4. Methods:Forty female Wistar rats were randomly divided into normal control group and model group. Rats in model group received 7. 5 mg/ mL oxazolone enema to induce experimental colitis. Rats received 0. 9%NaCl solution enema were served as normal controls. Macroscopic score and histological score were assessed. ELISA was used to determine serum and colon tissue inflammatory factor TNF-α,IL-4,IL-5,IL-10 levels. Protein expressions of tight junction protein claudin-1,-2,-4 were measured by immunohistochemistry and Western blotting. mRNA expressions of claudin-1,-2,-4 were determined by real-time PCR. Results:Compared with normal control group,macroscopic score and histological score were significantly increased (P < 0. 05),serum and colon tissue IL-4 and IL-5 levels were significantly increased (P < 0. 05)in model group,however,no significant differences in TNF-α and IL-10 levels were found between the two groups (P > 0. 05). mRNA and protein expressions of claudin-1,-4 were significantly decreased in model group than in normal control group (P < 0. 05),while mRNA and protein expressions of claudin-2 were significantly increased (P < 0. 05). Conclusions:Changes of distributions and expressions of tight junction protein claudin-1,-2,-4 are found in experimental colitis rats,which may lead to impaired epithelial barrier,and might be served as potential target for treatment of UC.