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Natural and experimental Helicobacter pullorum infection in Brown Norway rats
Laura D Cacioppo1, Michelle L Turk1, Zeli Shen1
1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, USA.
Abstract:
Helicobacter pullorum is an enterohepatic Helicobacter species (EHS) that was recently reported as a naturally acquired infection in mice. Faecal samples from 18 out of 20 Brown Norway (BN) rats, housed in the same barrier as the H. pullorum-infected mice, were positive for H. pullorum using species-specific PCR. In addition, we determined whether H. pullorum was able to persistently colonize the gastrointestinal tract and/or biliary tree and elicit tissue inflammation as well as a serum IgG response in BN rats. Six (four male, two female) 6-week-old, H. pullorum-negative BN rats were orally dosed with 4×10(8) c.f.u. of H. pullorum every other day for a total of three doses. At 2 weeks post-infection, all rats were H. pullorum-positive by faecal PCR. Five out of the six BN rats remained H. pullorum-positive for the entire 30 week study. PCR analysis of tissue collected at necropsy confirmed that the colon and caecum were the primary sites of H. pullorum colonization. Rats that were persistently colonized by H. pullorum had a sustained H. pullorum-specific IgG response measured by ELISA. Intestinal or hepatic pathology associated with H. pullorum infection was not noted. To our knowledge, this is the first report documenting that rats can be persistently colonized with an EHS that also infects humans.
Insights
Brown Norway rats can be persistently colonized by Helicobacter pullorum, an enterohepatic Helicobacter species (EHS). This study shows rats develop a sustained IgG response without significant pathology, highlighting a new animal model for EHS research.
Area of Science:
- Microbiology
- Infectious Diseases
- Animal Models
Background:
- Helicobacter pullorum is an enterohepatic Helicobacter species (EHS).
- Naturally acquired H. pullorum infections have been reported in mice.
- Brown Norway (BN) rats housed with infected mice showed H. pullorum in fecal samples.
Purpose of the Study:
- To determine if H. pullorum can persistently colonize the gastrointestinal tract and/or biliary tree in BN rats.
- To investigate if H. pullorum infection elicits tissue inflammation and a serum IgG response in BN rats.
- To establish a potential animal model for studying EHS infections relevant to human health.
Main Methods:
- Oral inoculation of H. pullorum into H. pullorum-negative BN rats.
- Monitoring fecal samples for H. pullorum presence using species-specific PCR.
- Assessing colonization sites (gastrointestinal tract, biliary tree) via PCR at necropsy.
- Measuring H. pullorum-specific IgG serum response using ELISA.
- Histopathological examination of intestinal and hepatic tissues.
Main Results:
- All inoculated rats were positive for H. pullorum by fecal PCR at 2 weeks post-infection.
- Five out of six rats remained persistently colonized for 30 weeks.
- The colon and cecum were identified as primary sites of H. pullorum colonization.
- Persistently colonized rats exhibited a sustained H. pullorum-specific IgG response.
- No significant intestinal or hepatic pathology was observed.
Conclusions:
- Rats can be persistently colonized by H. pullorum, an EHS that also infects humans.
- Persistent H. pullorum colonization in rats is associated with a sustained IgG response but not significant pathology.
- BN rats represent a novel and valuable animal model for studying enterohepatic Helicobacter species infections.
