Evidence for a primate origin of zoonotic Helicobacter suis colonizing domesticated pigs

Abstract

Helicobacter suis is the second most prevalent Helicobacter species in the stomach of humans suffering from gastric disease. This bacterium mainly inhabits the stomach of domesticated pigs, in which it causes gastric disease, but it appears to be absent in wild boars. Interestingly, it also colonizes the stomach of asymptomatic rhesus and cynomolgus monkeys. The origin of modern human-, pig- or non-human primate-associated H. suis strains in these respective host populations was hitherto unknown. Here we show that H. suis in pigs possibly originates from non-human primates. Our data suggest that a host jump from macaques to pigs happened between 100 000 and 15 000 years ago and that pig domestication has had a significant impact on the spread of H. suis in the pig population, from where this pathogen occasionally infects humans. Thus, in contrast to our expectations, H. suis appears to have evolved in its main host in a completely different way than its close relative Helicobacter pylori in humans.

Macroevolution of gastric Helicobacter species unveils interspecies admixture and time of divergence

“…410 kya. Coevolution between a microbe and its host generally results in decreased pathogenicity, but a disruption caused by jumps between hosts has been associated with an increase in disease severity, as shown for Staphylococcus aureus and recently also for H. suis [54,55]. Since infection with H. cetorum has been correlated with gastric ulcers in marine mammals [13,17], these animals are thus probably not the natural host.…”

PCR analysis and specific immunohistochemistry revealing a high prevalence of non‐Helicobacter pylori Helicobacters in Helicobacter pylori‐negative gastric disease patients in Japan: High susceptibility to an Hp eradication regimen

“…The differences in infection rates could come from the meat consumption patterns in Japan, as people in Tohoku and Kyushu regions were reported to eat more pork than beef compared to other regions. Pigs have already been confirmed to be a reservoir of Hs 27 . We were unable to obtain the infection rate in the general population in this study.…”

Presence of gastric Helicobacter species in children suffering from gastric disorders in Southern Turkey

“…A mixed infection with H. pylori and H. suis was present in one patient. MLST analysis showed that the strains of both H. suis‐ positive patients belonged to the porcine‐associated sequence types 1 and 4 …”

“…As H. suis naturally colonizes the stomach of pigs and non‐human primates, while H. heilmannii and H. ailurogastricus are mainly associated with dogs and cats, these animals might function as a reservoir for human infections. MLST analysis demonstrated that the H. suis strains from both patients were porcine associated . The exact route of transmission from animals to humans is not yet clear.…”