Fig. 1.

Viability of H. pylori in the presence of 1 mM H₂O₂ is restored by supplementation with OMVs. Bacteria were incubated at 37 °C in Iso-Sensitest broth, 5 % (v/v) FCS with 1 mM H₂O₂ and viability determined after 2.5 h by the Miles and Misra method. Triplicate means ± sd are shown. Bacterial viability was reduced by H₂O₂ treatment compared to the control in which H₂O₂ was inactivated using 0.1 % (w/v) bovine catalase (bKatA). Bacterial viability was restored to control levels by the addition of purified OMVs, in a dose-dependent manner. Asterisks indicate statistically significant differences compared to H₂O₂-treated bacteria without the addition of bKatA or OMVs (non-parametric Kruskal–Wallis test with multiple comparisons by Dunn’s test; multiplicity corrected P values reported; *P<0.05).