Nepalese Helicobacter pylori Genotypes Reflects a Geographical Diversity than a True Virulence Factor

Document Type: Research Articles

Authors

1 Civil service hospital, Minbhawan, Kathmandu, Nepal.

2 Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879 5593, Japan.

3 Department of Gastroenterology and Hepatology, Baylor College of Medicine and Michael DeBakey Veterans Affairs Medical Center, Houston, Texas 77030, USA.

4 Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital-Institute of Tropical Disease, Airlangga University, Surabaya 60115, Indonesia.

5 Department of Molecular Pathology, Oita University Faculty of Medicine, Yufu 879 5593, Japan.

Abstract

 
Background: The data about the association between Helicobacter pylori putative virulence factors; iceA and jhp0562/β-(1,3)galT with clinical outcomes are still controversial. We identified and analyzed two putative H. pylori virulence factors in Nepalese strains. Methods: The iceA and jhp0562/β-(1,3)galT allelic types were determined by polymerase chain reaction amplification. Histological analysis were classified according to the updated Sydney system and the Operative Link on Gastritis Assessment (OLGA) system. Results: Among 49 strains, iceA1 negative/iceA2 positive (iceA2-positive) was predominant type (57.1%, 28/49) and 20 (40.8%) were iceA1 positive/iceA2 negative. The remaining one (2.0%) was positive for both iceA1 and iceA2 (iceA1/iceA2-mixed). Patients infected with iceA1-positive strains tended to be higher OLGA score than iceA2-positive strains [1.45 [1] vs. 0.07 [0.5], P = 0.09, respectively). The jhp0562 negative/β-(1,3)galT positive was predominant type (25/51, 49.0%), followed by double positive for jhp0562/β-(1,3)galT (15/51, 29.4%) and jhp0562 positive/β-(1,3)galT negative (11/51, 21.6%). Activity in the corpus was significantly higher in jhp0562 negative/β-(1,3)galT positive than double positive of jhp0562/β-(1,3)galT positive [mean (median); 1.24 (1) vs. 0.73 (1), P = 0.03]. There was association between iceA and subtype of vacA signal region (e.g., s1a, s1b or s1c) and combination subtypes of signal and middle regions (e.g., s1a-m1c) (P = 0.02, r = 0.29; and P = 0.002, r = 0.42, respectively). In addition, jhp0562/β-(1,3)galT genotypes associated with cagA pre-EPIYA type (e.g., 6 bp-, 18 bp-, or no deletion-type) (P = 0.047, r = 0.15). Conclusion: The inconsistency results of the association between iceA, jhp0562/β-(1,3)galT and histological scores suggesting that these genes may associate with genetic heterogeneity rather than as a true virulence factor.

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