Enterohepatic Helicobacter Species Are Prevalent in Mice from Commercial and Academic Institutions in Asia, Europe, and North America (original) (raw)
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Journal of Clinical Microbiology, 2006
However, there is little information about the prevalence of EHS in noncommercial animal facilities. The aim of this study was to investigate the prevalence and the spread of EHS in specific-pathogen-free (SPF) mice. Fecal samples of 40 mouse lines were analyzed for members of the family Helicobacteraceae using a group-specific PCR targeting the 16S rRNA gene. Additional experiments were carried out to evaluate the spread of EHS among mice harbored in different caging systems. Helicobacter species were detected in 87.5% of the mouse lines tested. Five different Helicobacter species were identified: H. ganmani, H. hepaticus, H. typhlonicus, and the putative Helicobacter species represented by the isolates hamster B and MIT 98-5357. Helicobacter infection did not spread between animals in neighboring cages when individually ventilated cages were used; in contrast, when the mice were reared in open-air cages, EHS were found to spread from cage to cage. However, the spread was prevented by adding polycarbonate filter tops to the cages. When Helicobacter-negative and infected mice shared the same cage, transmission of the infection occurred in 100% within 2 weeks. Furthermore, we found that mice from commercial breeding facilities may carry undetected Helicobacter infections. Taken together, we show that infection with EHS may frequently occur and spread easily in mice reared under SPF conditions despite extensive safety precautions. Moreover, there is a high prevalence of rather uncommon Helicobacter species that may be a consequence of the current routine procedures used for health screening of SPF mice.
2004
Helicobacter pylori, as well as by other gastric and intestinal Helicobacter spp., but some murine enteric Helicobacter spp. cause hepatobiliary and intestinal tract diseases in specific inbred strains of laboratory mice. To identify these murine Helicobacter spp., we developed an assay based on PCR-denaturing gradient gel electrophoresis and pyrosequencing. Nine strains of mice, maintained in four conventional laboratory animal houses, were assessed for Helicobacter sp. carriage. Tissue samples from the liver, stomach, and small intestine, as well as feces and blood, were collected; and all specimens (n ؍ 210) were screened by a Helicobacter genus-specific PCR. Positive samples were identified to the species level by multiplex denaturing gradient gel electrophoresis, pyrosequencing, and a H. ganmani-specific PCR assay. Histologic examination of 30 tissue samples from 18 animals was performed. All mice of eight of the nine strains tested were Helicobacter genus positive; H. bilis, H. hepaticus, H. typhlonius, H. ganmani, H. rodentium, and a Helicobacter sp. flexispira-like organism were identified. Helicobacter DNA was common in fecal (86%) and gastric tissue (55%) specimens, whereas samples of liver tissue (21%), small intestine tissue (17%), and blood (14%) were less commonly positive. Several mouse strains were colonized with more than one Helicobacter spp. Most tissue specimens analyzed showed no signs of inflammation; however, in one strain of mice, hepatitis was diagnosed in livers positive for H. hepaticus, and in another strain, gastric colonization by H. typhlonius was associated with gastritis. The diagnostic setup developed was efficient at identifying most murine Helicobacter spp.
High Prevalence and Species Diversity of Helicobacter spp. Detected in Wild House Mice
Applied and Environmental Microbiology, 2012
15 PCR diagnostics detected 100% prevalence of Helicobacter in 425 wild house mice (Mus 16 musculus) from across Central Europe. Of seven species identified, the five most frequent 17 were H. rodentium (78%), H. typhlonius (53%), H. hepaticus (41%), H. bilis (30%) and H. 18 muridarum (1%). Double infections were more common (42%) than single (30%) and triple 19 (21%) infections. Wild house mice could be considered potential reservoirs of Helicobacter 20 for both humans and other vertebrates. 21 22
Infection and Immunity, 2003
It has been reported that Helicobacter hepaticus infection of mice leads to chronic hepatitis and hepatocarcinoma. Our aim was to monitor a cohort of 80 conventional A/J mice in which half of the mice were infected by H . hepaticus in order to study the evolution of the infection and the pathological changes in comparison to uninfected mice. H . hepaticus was detected by culture only in some colon and cecum specimens after 17 months of age, while PCR detected H . hepaticus in the intestines of all inoculated mice after only 5 months of infection. The percentage of mice in which H . hepaticus was detected in the gallbladder, bile ducts, and liver by PCR, as well as the number of bacteria present in the liver, tended to increase with increasing age and longer infection time. Anti- H . hepaticus immunoglobulin G antibodies were positive by enzyme-linked immunosorbent assay only in inoculated mice. Pathological findings were also more frequent as the mice grew older: fibrosis was presen...
Difficulties in the molecular diagnosis of helicobacter rodent infections
Veterinary Microbiology, 2009
Molecular diagnostic methods using the polymerase chain reaction (PCR) are the gold standard in Helicobacter diagnostics. Most rely on the amplification of parts of the 16S rRNA gene sequence. Therefore, the validity and accuracy of results depends heavily on the PCR design at the time of its publication even though new sequences are constantly published. Here we report inconsistency amongst different commercial laboratories in identifying Helicobacter hepaticus infection in commercially bred mice supposedly free of this infection. Furthermore, 3 out of 6 different commercial laboratories performing helicobacter testing on the same spiked faecal samples failed to detect and identify H.hepaticus. We designed a simple generic PCR assay that amplifies a 261 bp amplicon spanning two of the seven variable regions in the 16S rRNA of helicobacter. Using this assay together with an established generic assay designed by Bohr (Bohr et al., 2002) and then cloning and sequencing their products, we detected the H.hepaticus used in the study that three commercial laboratories failed to detect. We also think we can detect all the currently known species of helicobacter and hopefully the new ones as well. And we have been able to identify different species of helicobacter and their relative proportions infecting a single animal. This information has also shown that some helicobacters may have a much broader host range than originally reported.
2000
A spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the intestines of laboratory mice. The organism grew at 37 and 42°C under microaerobic and anaerobic conditions, did not hydrolyze urea, was weakly positive for catalase and oxidase, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and was resistant to cephalothin and nalidixic acid. This is the first ureasenegative, murine Helicobacter spp. isolated from intestines. Also, Helicobacter pullorum and this bacterium are unique among the genus Helicobacter in having nonsheathed flagella. The new bacterium appears to be part of the normal intestinal flora; although its pathogenic potential is unknown, this organism was also isolated from scid mice with diarrhea that were co-infected with Helicobacter bilis. On the basis of 16s rRNA gene sequence analysis data and biochemical and phenotypic criteria, the new organism is classified as a novel helicobacter, for which we propose the name Helicobacter rodentium. The type strain is MIT 95-1707 (= ATCC 700285).
Infection and Immunity, 1998
Hepatitis, proliferative typhlitis, and colitis were characterized in young adult and older SCID/NCr mice naturally infected with Helicobacter hepaticus . Liver lesions consisted of Kupffer, Ito, and oval cell hyperplasia along with multifocal to coalescing coagulative hepatocyte necrosis. Numerous Warthin-Starry-positive bacteria were observed in the parenchyma, and there were minimal to mild accumulations of monocytic cells and neutrophils. Proliferative typhlitis was characterized by moderate to marked mucosal epithelial cell hyperplasia with mild monocytic and neutrophilic infiltration. Minimal to mild colitis with mucosal epithelial cell hyperplasia of the colon was most marked in older mice. Comparable gastrointestinal lesions were not observed in uninfected control SCID/NCr mice. H. hepaticus was cultured from fetal viscera of 2 of 11 pups sampled late in gestation from infected SCID/NCr females, suggesting transplacental infection of H. hepaticus . As expected, most of the n...
Comparative Medicine, 2009
Infection of mouse colonies with Helicobacter spp. has become an increasing concern for the research community. Although Helicobacter infection may cause clinical disease, investigators may be unaware that their laboratory mice are infected because the pathology of Helicobacter species is host-dependent and may not be recognized clinically. The effects of Helicobacter infections are not limited to the gastrointestinal system and can affect reproduction, the development of cancers in gastrointestinal organs and remote organs such as the breast, responses to vaccines, and other areas of research. The data we present in this review show clearly that unintentional Helicobacter infection has the potential to significantly interfere with the reliability of research studies based on murine models. Therefore, frequent screening of rodent research colonies for Helicobacter spp. and the eradication of these pathogens should be key goals of the research community.