To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were ...To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.METHODSA collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.RESULTSThe strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.CONCLUSIONThe present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.展开更多
AIM： To evaluate the usefulness of stooI-PCR test for diagnosis of Helicobacter pylori （H pylon） infection in pediatric populations. METHODS： Based on endoscopic features （including nodular gastritis, erosive duo...AIM： To evaluate the usefulness of stooI-PCR test for diagnosis of Helicobacter pylori （H pylon） infection in pediatric populations. METHODS： Based on endoscopic features （including nodular gastritis, erosive duodenitis and ulcer） and/or a positive rapid urease test （RUT） obtained during endoscopy, 28 children from a group of children admitted to the Children＇s Medical Center of Tehran for persistent upper gastrointestinal problems were selected to compare biopsy-based tests with stool- PCR. Their gastric activity and bacterial density were graded by the updated Sydney system, and their first stool after endoscopy was stored at -70℃. Biopsies were cultured on modified campy-blood agar plates and identified by gram-staining, biochemical tests, and PCR. Two methods of phenol-chloroform and boiling were used for DNA extraction from H pylori isolates. Isolation of DNA from stool was performed using a stool DNA extraction kit （Bioneer Inc, Korea）. PCR was performed using primers for detection of vacA, cagA, and 16srRNA genes in both isolates and stool. RESULTS： Sixteen out of 28 child patients （57%） were classified as H pylori positive by biopsy-based tests, of which 11 （39%） were also positive by stool- PCR. Sensitivity and specificity of stool-PCR was 62.5% and 92.3% respectively. H pylori was observed in histological sections for 10 out of 11 stool-positive patients. Association was observed between higher score of H pylori in histology and positivity of stool- PCR. Also association was observed between the more severe form of gastritis and a positive stool-PCR. CONCLUSION： Association between higher score of H pylori in histology and a positive stool-PCR make it a very useful test for detection of H pylori active infection in children. We also suggest that a simple stool-PCR method can be a useful test for detection of Hpylori virulence genes in stool.展开更多
文摘To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.METHODSA collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.RESULTSThe strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.CONCLUSIONThe present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.
文摘AIM： To evaluate the usefulness of stooI-PCR test for diagnosis of Helicobacter pylori （H pylon） infection in pediatric populations. METHODS： Based on endoscopic features （including nodular gastritis, erosive duodenitis and ulcer） and/or a positive rapid urease test （RUT） obtained during endoscopy, 28 children from a group of children admitted to the Children＇s Medical Center of Tehran for persistent upper gastrointestinal problems were selected to compare biopsy-based tests with stool- PCR. Their gastric activity and bacterial density were graded by the updated Sydney system, and their first stool after endoscopy was stored at -70℃. Biopsies were cultured on modified campy-blood agar plates and identified by gram-staining, biochemical tests, and PCR. Two methods of phenol-chloroform and boiling were used for DNA extraction from H pylori isolates. Isolation of DNA from stool was performed using a stool DNA extraction kit （Bioneer Inc, Korea）. PCR was performed using primers for detection of vacA, cagA, and 16srRNA genes in both isolates and stool. RESULTS： Sixteen out of 28 child patients （57%） were classified as H pylori positive by biopsy-based tests, of which 11 （39%） were also positive by stool- PCR. Sensitivity and specificity of stool-PCR was 62.5% and 92.3% respectively. H pylori was observed in histological sections for 10 out of 11 stool-positive patients. Association was observed between higher score of H pylori in histology and positivity of stool- PCR. Also association was observed between the more severe form of gastritis and a positive stool-PCR. CONCLUSION： Association between higher score of H pylori in histology and a positive stool-PCR make it a very useful test for detection of H pylori active infection in children. We also suggest that a simple stool-PCR method can be a useful test for detection of Hpylori virulence genes in stool.
