Point Mutations at gyrA and gyrB Genes of Levofloxacin Resistant Helicobacter pylori Strains and Dual Resistance with Clarithromycin

High antibiotic resistance rates in Helicobacter pylori strains in Turkey over 20 years: implications for gastric disease treatment

OBJECTIVE

Helicobacter pylori (Hp) eradication therapy is crucial for preventing the development of gastritis, peptic ulcers, and gastric cancer. An increase in resistance against antibiotics used in the eradication of Hp is remarkable. This meta-analysis aims to examine the resistance rates of Hp strains isolated in Turkey over the last 20 years against clarithromycin (CLR), metronidazole (MTZ), levofloxacin (LVX), tetracycline (TET), and amoxicillin (AMX) antibiotics.

BASIC METHODS

Literature search was carried out in electronic databases, by searching articles published in Turkish and English with the keywords ' helicobacter pylori ' or 'Hp' and 'antibiotic resistance' and 'Turkey'. That meta-analysis was carried out using random-effect model. First, the 20-year period data between 2002 and 2021 in Turkey were planned to be analyzed. As a second stage, the period between 2002 and 2011 was classified as Group 1, and the period between 2012 and 2021 as Group 2 for analysis, with the objective of revealing the 10-year temporal variation in antibiotic resistance rates.

MAIN RESULTS

In gastric biopsy specimens, 34 data from 29 studies were included in the analysis. Between 2002-2021, CLR resistance rate was 30.9% (95% CI: 25.9-36.2) in 2615 Hp strains. Specifically, in Group 1, the CLR resistance rate was 31% in 1912 strains, and in Group 2, it was 30.7% in 703 strains. The MTZ resistance rate was found to be 31.9% (95% CI: 19.8-45.4) in 789 strains, with rates of 21.5% in Group 1 and 46.6% in Group 2. The overall LVX resistance rate was 25.6%, with rates of 26.9% in Group 1 and 24.8% in Group 2. The 20-year TET resistance rate was 0.8%, with 1.50% in Group 1 and 0.2% in Group 2. The overall AMX resistance rate was 2.9%, 3.8% between 2002-2011, and 1.4% between 2012-2021.

PRINCIPAL CONCLUSION

Hp strains in Turkey exhibit high resistance rates due to frequent use of CLR, MTZ, and LVX antibiotics. However, a significant decrease has been observed in TET and AMX resistance to Hp in the last 10 years. Considering the CLR resistance rate surpasses 20%, we suggest reconsidering the use of conventional triple drug therapy as a first-line treatment. Instead, we recommend bismuth-containing quadruple therapy or sequential therapies (without bismuth) for first-line treatment, given the lower rates of TET and AMX resistance. Regimens containing a combination of AMX, CLR, and MTZ should be given priority in second-line therapy. Finally, in centers offering culture and antibiogram opportunities, regulating the Hp eradication treatment based on the antibiogram results is obviously more appropriate.

Next-Generation Sequencing-Based Study of Helicobacter pylori Isolates from Myanmar and Their Susceptibility to Antibiotics

Evaluation of Helicobacter pylori resistance to antibiotics is crucial for treatment strategy in Myanmar. Moreover, the genetic mechanisms involved remain unknown. We aimed to investigate the prevalence of H. pylori infection, antibiotic resistance, and genetic mechanisms in Myanmar. One hundred fifty patients from two cities, Mawlamyine (n = 99) and Yangon (n = 51), were recruited. The prevalence of H. pylori infection was 43.3% (65/150). The successfully cultured H. pylori isolates (n = 65) were tested for antibiotic susceptibility to metronidazole, levofloxacin, clarithromycin, amoxicillin, and tetracycline by Etest, and the resistance rates were 80%, 33.8%, 7.7%, 4.6%, and 0%, respectively. In the multidrug resistance pattern, the metronidazole–levofloxacin resistance was highest for double-drug resistance (16/19; 84.2%), and all triple-drug resistance (3/3) was clarithromycin–metronidazole–levofloxacin resistance. Twenty-three strains were subjected to next-generation sequencing to study their genetic mechanisms. Interestingly, none of the strains resistant to clarithromycin had well-known mutations in 23S rRNA (e.g., A2142G, A2142C, and A2143G). New type mutation genotypes such as pbp1-A (e.g., V45I, S/R414R), 23S rRNA (e.g., T248C), gyrA (e.g., D210N, K230Q), gyrB (e.g., A584V, N679H), rdxA (e.g., V175I, S91P), and frxA (e.g., L33M) were also detected. In conclusion, the prevalence of H. pylori infection and its antibiotic resistance to metronidazole was high in Myanmar. The H. pylori eradication regimen with classical triple therapy, including amoxicillin and clarithromycin, can be used as the first-line therapy in Myanmar. In addition, next-generation sequencing is a powerful high-throughput method for identifying mutations within antibiotic resistance genes and monitoring the spread of H. pylori antibiotic-resistant strains.