Molecular Epidemiology and Outcome of Helicobacter pylori Infection in Thailand: a Cultural Cross Roads

Authors

  • Ratha-Korn Vilaichone,

    1. Gastroenterology Unit, Department of Medicine, Thammasat University Hospital, Pathumthani, Thailand;
    2. Department of Medicine, Michael E. Debakey Veterans Affairs Medical Center and Baylor College of Medicine, TX, USA;
    Search for more papers by this author
  • Varocha Mahachai,

    1. Gastroenterology Unit, Department of Medicine;
    Search for more papers by this author
  • Somying Tumwasorn,

    1. Department of Microbiology, Chulalongkorn University Hospital, Bangkok, Thailand
    Search for more papers by this author
  • Jeng-Yih Wu,

    1. Department of Medicine, Michael E. Debakey Veterans Affairs Medical Center and Baylor College of Medicine, TX, USA;
    Search for more papers by this author
  • David Y. Graham,

    1. Department of Medicine, Michael E. Debakey Veterans Affairs Medical Center and Baylor College of Medicine, TX, USA;
    Search for more papers by this author
  • Yoshio Yamaoka

    Corresponding author
    1. Department of Medicine, Michael E. Debakey Veterans Affairs Medical Center and Baylor College of Medicine, TX, USA;
      Reprint requests to: Yoshio Yamaoka, MD, PhD, Michael E. Debakey Veterans Affairs Medical Center, Medicine/GI (111D), 2002 Holcombe Blvd. Houston, Texas 77030 USA. Tel.: [713] 794–7597; Fax: [713] 790–1040; E-mail: yyamaoka@bcm.tmc.edu
    Search for more papers by this author

Reprint requests to: Yoshio Yamaoka, MD, PhD, Michael E. Debakey Veterans Affairs Medical Center, Medicine/GI (111D), 2002 Holcombe Blvd. Houston, Texas 77030 USA. Tel.: [713] 794–7597; Fax: [713] 790–1040; E-mail: yyamaoka@bcm.tmc.edu

ABSTRACT

Background.  Thailand is at the cultural cross roads between East and South Asia. It has been suggested that this is also the region where the predominant Helicobacter pylori (H. pylori) genotype changes from East Asian to South Asian.

Methods.  We compared the molecular epidemiology and outcome of H. pylori infections among different ethnic groups in Thailand (Thai, Thai-Chinese and Chinese). H. pylori isolates were genotyped by polymerase chain reaction based on cagA, cag right end junction and vacA genotypes.

Results.  Ninety-eight isolates from 38 ethnic Thai, 20 ethnic Chinese and 40 Thai-Chinese were categorized into East Asian (45%), South/Central Asian (26%), Western (1%) or mixed type (29%). The East Asian genotype was the most common among Chinese (85%) and Thai-Chinese (55%) (p < .01 compared to ethnic Thai). The ethnicity of the mother among mixed Thai-Chinese marriages predicted the genotype of the child's H. pylori (e.g. when the mother was Chinese, 84% had East Asian type vs. 29% when the mother was Thai) (p < .001). Gastric cancer was common among ethnic Chinese with East Asian genotype (e.g. all Chinese with gastric cancer or peptic ulcer disease had East Asian genotype, whereas only 40% of Chinese with gastritis had this genotype).

Conclusions.  Immigration, intermarriage and the variety of H. pylori genotypes in Thailand suggest that Thailand is an ideal site for epidemiological studies attempting to relate H. pylori genotypes and host factors to outcome. Our data also support the hypothesis that the primary caretaker of the children is most likely the source of the infection.

Ancillary