Monitoring a mouse colony for Helicobacter bilis using a Helicobacter-genus-specific nested PCR

Eradication of Helicobacter bilis and H. hepaticus from infected mice by using a medicated diet

Infection of laboratory mice with Helicobacter spp. is a serious problem for many laboratory animal facilities worldwide. Rederivation and antibiotic treatment are two of the most common methods used to eliminate the bacterial infection from rodent colonies. Forty-seven newly imported mice were suspected to be positive for Helicobacter infection based on PCR analysis of pooled fecal samples from sentinel animals. We treated the mice with a medicated feed containing four antibiotic compounds (amoxicillin, clarithromycin, metronidazole, omeprazole). After eight weeks of continuous administration the animals were negative for H. bilis and H. hepaticus. Frequent retesting of the animals for up to one year proved that the mouse colony remained negative for Helicobacter spp.

Extragastric manifestations of Helicobacter pylori infection--other Helicobacter species

Recent studies have indicated a strong link between Helicobacter pylori and idiopathic thrombocytopenic purpura and iron deficiency anemia. Interesting results have also been obtained for ischemic heart disease, though most putative associations between H. pylori infection and extragastric disease remain speculative. With regard to other Helicobacter species, Helicobacter felis has been shown to play a role in gastric carcinogenesis in mouse models. An increased susceptibility to cholesterol gallstone formation has been described in animals fed a lithogenic diet and infected with Helicobacter bilis, or co-infected with Helicobacter hepaticus and Helicobacter rodentium. Finally, enterohepatic Helicobacter species have also been exploited to better understand inflammatory bowel disease.

Detection, eradication, and research implications of Helicobacter infections in laboratory rodents

Researchers first isolated and characterized Helicobacter hepaticus in 1994 as a cause of hepatitis that progressed to hepatocellular carcinoma in A/JCr mice. During the past decade, isolation and characterization of additional novel helicobacters from rodents has continued. In addition to causing overt disease, rodent helicobacter infections are important because intercurrent disease in select models will confound research data. Emerging evidence suggests that inflammatory responses to enterohepatic helicobacter infections may alter host responses to other experimental stimuli in unanticipated ways. Additionally, scientists have experimentally infected a variety of inbred mouse strains and genetically engineered mice with a variety of Helicobacter spp. isolated from rodents, birds, and higher mammals (including humans) to develop animal models of gastrointestinal diseases as well as idiopathic human disease syndromes. This review highlights current information about helicobacter infections in laboratory rodents and provides recommendations for the detection and eradication of these infections. The authors discuss the impact of subclinical and clinical disease and offer recommendations for managing helicobacter-free rodent colonies.