Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 5, 671

Antimicrobial Susceptibility and Clarithromycin Resistance Patterns of Helicobacter Pylori Clinical Isolates in Vietnam


Antimicrobial Susceptibility and Clarithromycin Resistance Patterns of Helicobacter Pylori Clinical Isolates in Vietnam

Camelia Quek et al. F1000Res.


Helicobacter pylori is a gastric pathogen that causes several gastroduodenal disorders such as peptic ulcer disease and gastric cancer. Eradication efforts of H. pylori are often hampered by antimicrobial resistance in many countries, including Vietnam. Here, the study aimed to investigate the occurrence of antimicrobial resistance among H. pylori clinical isolates across 13 hospitals in Vietnam. The study further evaluated the clarithromycin resistance patterns of H. pylori strains. In order to address the study interests, antimicrobial susceptibility testing, epsilometer test and PCR-based sequencing were performed on a total of 193 strains isolated from patients, including 136 children (3-15 years of age) and 57 adults (19-69 years of age). Antimicrobial susceptibility testing showed that the overall resistance to amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline was 10.4%, 85.5%, 24.4%, 37.8%, and 23.8% respectively. The distribution of minimum inhibitory concentrations (MICs) of clarithromycin-resistant strains was 85.5% with MIC >0.5 μg/mL. The majority of the clarithromycin resistant isolates (135 of 165 subjects) have MICs ranging from 2 μg/mL to 16 μg/mL. Furthermore, sequencing detection of mutations in 23S rRNA gene revealed that strains resistant and susceptible to clarithromycin contained both A2143G and T2182C mutations. Of all isolates, eight clarithromycin-resistant isolates (MIC >0.5 μg/mL) had no mutations in the 23S rRNA gene. Collectively, these results demonstrated that a proportion of clarithromycin-resistant H. pylori strains, which are not related to the 23S rRNA gene mutations, could be potentially related to other mechanisms such as the presence of an efflux pump or polymorphisms in the CYP2C19 gene. Therefore, the present study suggests that providing susceptibility testing prior to treatment or alternative screening strategies for antimicrobial resistance is important for future clinical practice. Further studies on clinical guidelines and treatment efficacy are pivotal for successful eradication of H. pylori infection.

Keywords: 23S rRNA; Helicobacter pylori; antimicrobial resistance; gastric ulcer; mutation.

Conflict of interest statement

Competing interests: The authors declare that they have no competing interests.


Figure 1.
Figure 1.. Antimicrobial resistance rate of Helicobacter pylori isolates from Vietnamese children and adults.
The graph displays the resistance rate of amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline in both children and adults. Among the antimicrobial agents, clinical isolates resistant to levofloxacin is significantly higher ( p = 0.0103) in adults than in children.
Figure 2.
Figure 2.. Minimum inhibitory concentration values of clarithromycin susceptible and resistant isolates in children and adults.
The graph shows the number of isolates across a range of minimum inhibitory concentration values of clarithromycin. The total number of clarithromycin susceptible and resistant isolates is 24 and 165, respectively. Majority of clinical isolates resistant to clarithromycin have MIC values ranging from 2 μg/mL to 16 μg/mL.

Similar articles

See all similar articles

Cited by 4 PubMed Central articles


    1. Suerbaum S, Michetti P: Helicobacter pylori infection. N Engl J Med. 2002;347(15):1175–1186. 10.1056/NEJMra020542 - DOI - PubMed
    1. Peek RM Jr, Blaser MJ: Helicobacter pylori and gastrointestinal tract adenocarcinomas. Nat Rev Cancer. 2002;2(1):28–37. 10.1038/nrc703 - DOI - PubMed
    1. Lacy BE, Rosemore J: Helicobacter pylori: ulcers and more: the beginning of an era. J Nutr. 2001;131(10):2789S–2793S. - PubMed
    1. Eusebi LH, Zagari RM, Bazzoli F: Epidemiology of Helicobacter pylori infection. Helicobacter. 2014;19(Suppl 1):1–5. 10.1111/hel.12165 - DOI - PubMed
    1. Hoang TT, Bengtsson C, Phung DC, et al. : Seroprevalence of Helicobacter pylori infection in urban and rural Vietnam. Clin Diagn Lab Immunol. 2005;12(1):81–85. 10.1128/CDLI.12.1.81-85.2005 - DOI - PMC - PubMed

Grant support

This work was supported by the Nam Khoa-Biotek and Nguyen Tri Phuong hospital.

LinkOut - more resources