AIM: To evaluate the utility of the string test to detect genotypic clarithromycin-resistant Helicobacter pylori (H. pylori) by polymerase chain reaction (PCR)-restriction fragment length polymorphism. METHODS: Patients undergoing endoscopic examinations were enrolled in the present study. String tests were done on the next day of endoscopy. Segments of 23S rRNA were amplified from DNA obtained from string tests. PCR-restriction fragment length polymorphism was accomplished by restriction enzymes BbsI and BsaI recognizing the mutation site A to G at 2143 or at 2142 of 23S rRNA domain V, respectively. RESULTS: One hundred and thirty-four patients with H. pylori infection underwent string tests. To compare phenotypic resistance, 43 isolates were successfully cultured in 79 patients in whom 23S rRNA was successfully amplified. Of five patients with clarithromycin-resistant H. pylori, 23S rRNA of H. pylori isolates from four patients could be digested by BsaI. In 38 susceptible isolates, 23S rRNA of H. pylori isolates from 36 patients could not be digested by either BsaI or BbsI. The sensitivity and specificity of the string test to detect genotypic clarithromycin resistance were 66.7% and 97.3%, respectively. Positive and negative predictive values were 80% and 94.7%, respectively. CONCLUSION: String test with molecular analysis is a less invasive method to detect genotypic resistance before treatment. Further large-scale investigations are necessary to confirm our results.
AIM: To evaluate the utility of the string test to detect genotypic clarithromycin-resistant Helicobacter pylori (H. pylori) by polymerase chain reaction (PCR)-restriction fragment length polymorphism. METHODS:Patients undergoing endoscopic examinations were enrolled in the present study. String tests were done on the next day of endoscopy. Segments of 23S rRNA were amplified from DNA obtained from string tests. PCR-restriction fragment length polymorphism was accomplished by restriction enzymes BbsI and BsaI recognizing the mutation site A to G at 2143 or at 2142 of 23S rRNA domain V, respectively. RESULTS: One hundred and thirty-four patients with H. pyloriinfection underwent string tests. To compare phenotypic resistance, 43 isolates were successfully cultured in 79 patients in whom 23S rRNA was successfully amplified. Of five patients with clarithromycin-resistant H. pylori, 23S rRNA of H. pylori isolates from four patients could be digested by BsaI. In 38 susceptible isolates, 23S rRNA of H. pylori isolates from 36 patients could not be digested by either BsaI or BbsI. The sensitivity and specificity of the string test to detect genotypic clarithromycin resistance were 66.7% and 97.3%, respectively. Positive and negative predictive values were 80% and 94.7%, respectively. CONCLUSION: String test with molecular analysis is a less invasive method to detect genotypic resistance before treatment. Further large-scale investigations are necessary to confirm our results.
Entities:
Keywords:
Clarithromycin resistance; Helicobacter pylori; Polymerase chain reaction-restriction fragment length polymorphism; String test
Authors: Y Yamaoka; M S Osato; A R Sepulveda; O Gutierrez; N Figura; J G Kim; T Kodama; K Kashima; D Y Graham Journal: Epidemiol Infect Date: 2000-02 Impact factor: 2.451
Authors: J Versalovic; D Shortridge; K Kibler; M V Griffy; J Beyer; R K Flamm; S K Tanaka; D Y Graham; M F Go Journal: Antimicrob Agents Chemother Date: 1996-02 Impact factor: 5.191
Authors: Phabiola M Herrera; Melissa Mendez; Billie Velapatiño; Billie Velapatiõ; Livia Santivañez; Livia Santivaez; Jacqueline Balqui; S Alison Finger; Jonathan Sherman; Mirko Zimic; Lilia Cabrera; Jose Watanabe; Carlos Rodríguez; Robert H Gilman; Douglas E Berg Journal: J Clin Microbiol Date: 2008-10-08 Impact factor: 5.948