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

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.