Search results for "CagA"
showing 4 items of 14 documents
Helicobacter pylori: clonal population structure and restricted transmission within families revealed by molecular typing.
2000
ABSTRACT Helicobacter pylori infects up to 50% of the human population worldwide. The infection occurs predominantly in childhood and persists for decades or a lifetime. H. pylori is believed to be transmitted from person to person. However, tremendous genetic diversity has been reported for these bacteria. In order to gain insight into the epidemiological basis of this phenomenon, we performed molecular typing of H. pylori isolates from different families. Fifty-nine H. pylori isolates from 27 members of nine families were characterized by using restriction fragment length polymorphism analysis of five PCR-amplified genes, by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA, and …
vacA Genotypes and Genetic Diversity in Clinical Isolates of Helicobacter pylori
1998
ABSTRACT Genetic diversity in Helicobacter pylori strains may affect the function and antigenicity of virulence factors associated with bacterial infection and, ultimately, disease outcome. In this study, DNA diversity of H. pylori isolates was examined by analysis of vacA genotypes and by restriction fragment length polymorphism (RFLP) analysis of H. pylori -associated genes ( vacA , cagA , flaA , ureAB , and ureCD ). Thirty-seven H. pylori isolates from 26 patients were successfully classified into distinct vacA allelic genotypes. The signal sequence allele s1 (31 of 37) predominated over the s2 allele (6 of 37) and was significantly associated with the occurrence (past or present) of gas…
Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily
2015
The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of case…
Identifying the Profile of Helicobacter pylori–Negative Gastric Cancers: A Case-Only Analysis within the Stomach Cancer Pooling (StoP) Project
2022
Abstract Background: The prevalence of Helicobacter pylori–negative gastric cancer (HpNGC) can be as low as 1%, when infection is assessed using more sensitive tests or considering the presence of gastric atrophy. HpNGC may share a high-risk profile contributing to the occurrence of cancer in the absence of infection. We estimated the proportion of HpNGC, using different criteria to define infection status, and compared HpNGC and positive cases regarding gastric cancer risk factors. Methods: Cases from 12 studies from the Stomach cancer Pooling (StoP) Project providing data on H. pylori infection status determined by serologic test were included. HpNGC was reclassified as positive (eight st…