Background Helicobacter pylori infected children from coastal Tumaco, Colombia have more parasitism, and adults have lower gastric cancer risk compared to high altitude Pasto/Tuquerres residents. Because helminth and Toxoplasma gondii infections alter helicobacter gastritis in rodent models, we determined if seropositivity to Ascaris lumbricoides or T. gondii was associated with Th2-IgG1 or Th1-IgG2 responses to H. pylori. Methods Sera (240) from the two populations were evaluated for A. lumbricoides and T. gondii seropositivity and results correlated with IgE and IgG isotype responses to H. pylori. Results Most Tumaco children and adults were seropositive for A. lumbricoides (89%, 66%), T. gondii (59%, 98%) or both (45%, 66%). In contrast, seropositivity among Pasto/Tuquerres children was much lower (9% A. lumbricoides, 11% T. gondii and 2% dual positive) but increased in adults (58% A. lumbricoides, 82% T. gondii and 41% dual positive). A. lumbricoides seropositivity correlated with elevated IgE and anti-inflammatory Th2-IgG1 responses to H. pylori, while Toxoplasma gondii seropositivity was linked to elevated IgE, pro-inflammatory Th1-IgG2, IgG3 and IgG4 responses to H. pylori. Individuals with high T. gondii titers had reduced Th1-IgG2, IgG3 and IgG4 responses to Helicobacter pylori. Conclusions Results support regional differences for childhood parasitism and indicate A. lumbricoides and T. gondii infections may impact inflammatory responses to H. pylori and partially explain differences in gastric cancer risk in Colombia.

Background Aged hamsters naturally infected with novel Helicobacter spp. classified in the H. bilis cluster develop hepatobiliary lesions and typhlocolitis. Methods To determine if enterohepatic H. spp. contribute to disease, Helicobacter-free hamsters were experimentally infected with H. spp. after suppression of intestinal bacteria by tetracycline treatment of dams and pups. After antibiotic withdrawal, weanlings were gavaged with 4 H. bilis-like Helicobacter spp. isolated from hamsters or H. bilis ATCC 43879 isolated from human feces, and compared to controls (n = 7 per group). Results H. bilis 43879 dosed hamsters were necropsied at 33 WPI due to lack of detectable infection by fecal PCR; at necropsy, 5/7 were weakly PCR positive but lacked intestinal lesions. The remaining hamsters were maintained for ~95 WPI; chronic H. spp. infection in hamsters (6/7) was confirmed by PCR, bacterial culture, FISH and ELISA. Hamsters had mild to moderate typhlitis, and three of the male H. spp. infected hamsters developed small intestinal lymphoma, in contrast to one control. Of the three lymphomas in H. spp. infected hamsters, one was a focal ileal MALT B cell lymphoma, while the other two were multicentric small intestinal large B cell lymphomas involving both the MALT and extra-MALT mucosal sites with lymphoepithelial lesions. The lymphoma in the control hamster was a diffuse small intestinal lymphoma with a mixed population of T and B cells. Conclusions Results suggest persistent H. spp. infection may augment risk for gastrointestinal MALT origin lymphomas. This model is consistent with H. pylori/heilmannii associated MALT lymphoma in humans and could be further utilized to investigate mechanisms of intestinal lymphoma development.

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BackgroundThe development of a mouse model as an in vivo pathogenicity screening tool for Brachyspira spp. has advanced the study of these economically important pathogens in recent years. However, none of the murine models published to date have been used to characterize the clinical signs of disease in mice, instead focusing on pathology following oral inoculation with various Brachyspira spp. The experiments described herein explore modifications of published models to characterize faecal consistency, faecal shedding and pathology in mice challenged with “Brachyspira hampsonii” clade II (Bhamp).Methods and resultsIn Experiment 1, 24 CF-1 mice were randomly allocated to one of three inoculation groups: sham (Ctrl), Bhamp, or B. hyodysenteriae (Bhyo; positive control). Half of each group was fed normal mouse chow (RMH) while the other received a low-zinc diet (TD85420). In Experiment 2, eight CF-1 mice and nine C3H/HeN mice were divided into Ctrl or Bhamp inoculation groups, and all fed TD85420. In Experiment 1, mice fed TD85420 demonstrated more severe mucoid faeces (P = 0.001; Kruskal Wallis) and faecal shedding for a significantly greater number of days (P = 0.005; Kruskal Wallis). Mean faecal scores of Bhamp inoculated mice trended higher than Ctrl (P = 0.06; Wilcoxon rank-sum) as did those of Bhyo mice (P = 0.0; Wilcoxon rank-sum). In Experiment 2, mean faecal scores of inoculated CF-1 mice were significantly greater than in C3H mice (P = 0.049; Kruskal Wallis) but no group differences in faecal shedding were observed. In both experiments, mice clustered based on the severity of colonic and caecal histopathology but high lesion scores were not always concurrent with high fecal scores.ConclusionIn our laboratory, CF-1 mice and the lower-zinc TD85420 diet provide a superior murine challenge model of “Brachyspira hampsonii” clade II.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-1166-5) contains supplementary material, which is available to authorized users.