Characterization of <b><i>Helicobacter pylori tlyA</i></b> and Its Association with Bacterial Density

Abstract

&lt;b&gt;&lt;i&gt;Background:&lt;/i&gt;&lt;/b&gt; In the recent studies, a less virulent &lt;i&gt;Helicobacter pylori&lt;/i&gt; variant could still colonize the human stomach and induce gastric inflammation, suggesting the involvement of other virulence factors, such as TlyA hemolysin. Nevertheless, the association of TlyA in the pathogenesis of &lt;i&gt;H. pylori&lt;/i&gt; infection remains unclear. We investigated the &lt;i&gt;tlyA&lt;/i&gt; profile and determined its relationship with gastritis severity. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; An observational study was conducted using DNA stocks and secondary data from previous studies. The &lt;i&gt;tlyA&lt;/i&gt; variant was examined by NGS and confirmed with polymerase chain reaction. Gastritis severity was categorized by the Updated Sydney System. The relationship between a variant of &lt;i&gt;tlyA&lt;/i&gt; and gastritis severity was determined, in which discrete variables were tested using the χ&lt;sup&gt;2&lt;/sup&gt; test or Fisher exact test. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; Two &lt;i&gt;H. pylori tlyA&lt;/i&gt; variants were observed and characterized as &lt;i&gt;tlyA1&lt;/i&gt; and &lt;i&gt;tlyA2&lt;/i&gt;. We noted a unique variant in the amino acid sequence 32–35 that is exclusively detected among &lt;i&gt;H. pylori&lt;/i&gt; isolated from the Papua island. In addition, we observed that the &lt;i&gt;tlyA&lt;/i&gt; variant had a significant association with the &lt;i&gt;H. pylori&lt;/i&gt; density in the antral (&lt;i&gt;p&lt;/i&gt; = 0.002). Histological analyses revealed that TlyA1 was associated with higher &lt;i&gt;H. pylori&lt;/i&gt; density than TlyA2. However, we did not observe any significant association of &lt;i&gt;tlyA&lt;/i&gt; with the infiltration of inflammation cells. &lt;b&gt;&lt;i&gt;Conclusions:&lt;/i&gt;&lt;/b&gt; We observed 2 &lt;i&gt;tlyA&lt;/i&gt; variants (&lt;i&gt;tlyA1&lt;/i&gt; and &lt;i&gt;tlyA2&lt;/i&gt;). A significant association of &lt;i&gt;tlyA&lt;/i&gt; with bacterial density suggested that &lt;i&gt;tlyA&lt;/i&gt; plays a more significant role in the colonization process than its influence on the severity of inflammation in gastric mucosa.

Novel Helicobacter pylori-associated hemolysis Hp0499 and Hp1490 and its association with severity of gastritis

“…Another hemolysin factor, tylA, showed a significant association with the density of the bacteria, suggesting a more prominent role in colonization rather than inflammation. 29 In addition, a previous report showed that both pldAand tlyAnegative mutants could efficiently colonize a mouse model of H. pylori. This finding suggests that hemolysin activity is significantly associated with the colonization process and subsequent pathogenic pathway activation.…”