Time Trends in the Prevalence ofHelicobacter pyloriInfection and Future Directions in Korea

The Prevalence of Multidrug Resistance of Helicobacter pylori and Its Impact on Eradication in Korea from 2017 to 2019: A Single-Center Study

Antimicrobial resistance is one of the major factors determining the efficacy of Helicobacter pylori eradication therapy. This study aimed to estimate the recent prevalence of multidrug resistance of H. pylori and its impact on eradication in Korea. A total of 174 patients were prospectively enrolled at Chung-Ang University Hospital from 2017 to 2019. H. pylori strains were isolated from the gastric body and antrum. The minimum inhibitory concentrations of antibiotics were determined by the serial twofold agar dilution method. Eradication results were reviewed and analyzed in connection with antibiotic resistance. The prevalence of H. pylori infection was 51.7% (90/174). The culture success rate was 77.8% (70/90). The resistance rates for clarithromycin, metronidazole, amoxicillin, tetracycline, levofloxacin, and moxifloxacin were 28.6% (20/70), 27.1% (19/70), 20.0% (14/70), 18.6% (13/70), 42.9% (30/70), and 42.9% (30/70), respectively. The multidrug resistance (resistance to two or more classes of antimicrobials) rate was 42.9% (30/70). Dual resistance to clarithromycin and metronidazole was confirmed in 8.6% (6/70). Eradication with a first-line treatment was successful in 75% (36/48), and those who received second-line treatment all achieved successful eradication. The rate of multidrug resistance is increasing, and standard triple therapy (STT) is no longer an acceptable first-line option for H. pylori eradication in Korea.

Changing trends in lymphoid neoplasm distribution in South Korea: analysis of 8615 cases from a single institute, 1997-2016: An observational study

The purpose of this study was to evaluate changes in the proportion of lymphoid neoplasm subtypes in South Korea. A total of 8615 cases of lymphoid neoplasms diagnosed in 1997-2016 at Samsung Medical Center in South Korea were classified according to the 2008 World Health Organization system. The total number and proportion of lymphoid neoplasms were compared between these two decades, with data from nationwide studies, and with other countries. To evaluate changes in the proportion of subtypes, crude rate of each subtype per 100 lymphoma patients during each decade and age adjusted rate were calculated. There were 3024 patients with lymphoid neoplasm in 1997-2006, and 5591 in 2007-2016, which represents an average increase of 1.85 times over the 20-year study period. Crude rate and age adjusted rate were increased in Hodgkin's lymphoma and mature B cell lymphoma while precursor lymphoid neoplasms and mature T cell lymphoma were decreased. Among B cell neoplasms, age adjusted rate of plasma cell neoplasm, follicular lymphoma, mantle cell lymphoma increased while there was no significant change in extranodal marginal zone lymphoma and Burkitt lymphoma. The increase in follicular lymphoma was due to the increases in nodal follicular lymphoma of low grade and duodenal-type follicular lymphoma. These results are consistent with the dynamics of causative factors, including socioeconomic factors, in Korea.

The analysis of virulence factors and antibiotic resistance between Helicobacter pylori strains isolated from gastric antrum and body

Background

Individuals can be infected with multiple strains of Helicobacter pylori. However, the differences among co-infecting strains have not been well analyzed yet. This study aimed to investigate whether the virulence factors and antibiotic resistance patterns of H. pylori differ between strains isolated from different locations of the stomach in the same patient.

Methods

H. pylori isolates were obtained from the antrum and body of the stomach. Genetic differences were examined by random amplified polymorphic DNA (RAPD) fingerprinting. Antibiotic resistance was assessed using the agar dilution method. Virulence factors were identified by polymerase chain reaction and DNA sequencing.

Results

Among 80 patients, co-infection by two H. pylori strains was detected in 10 patients. Among the 10 pairs of H. pylori strains, differences in antibiotic resistance patterns were detected in 7 pairs (clarithromycin, 1 patient; quinolone, 3 patients; metronidazole, 4 patients) and differences in virulence factors were detected in 5 pairs. The cagA virulence gene was detected in all 10 patients, and 2 patients had H. pylori strains with different EPIYA motifs. Differences in vacA genotypes were detected in 4 patients.

Conclusions

Co-infection by two H. pylori strains was confirmed by RAPD fingerprinting. Frequently, two H. pylori strains obtained from a single host differed in their virulence factors and antibiotic resistance patterns. Co-infection by multiple H. pylori strains could undermine the success of eradication therapy and should be considered when interpreting the results of antimicrobial susceptibility tests.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-1062-5) contains supplementary material, which is available to authorized users.