Prevalence and Spread of Enterohepatic Helicobacter Species in Mice Reared in a Specific-Pathogen-Free Animal Facility

Abstract

Infections with enterohepatic Helicobacter species (EHS) can change the results of animal experiments.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.

Polyclonal MHC Ib-Restricted CD8+ T Cells Undergo Homeostatic Expansion in the Absence of Conventional MHC-Restricted T Cells

“…Ϫ/Ϫ mice are particularly susceptible to common specificpathogen free mouse facility infections, particularly Helicobacter, which is very prevalent and is not routinely tested for at most institutions (67). In our K bϪ/Ϫ D bϪ/Ϫ CIITA Ϫ/Ϫ mouse colony, all mice that developed a rectal prolapse were also Helicobacter positive by PCR of feces, similar to findings in IL-10 Ϫ/Ϫ mice (68,69).…”

Prevalence of Helicobacter hepaticus, Murine Norovirus, and Pneumocystis carinii and Eradication Efficacy of Cross-Fostering in Genetically Engineered Mice

“…We also studied the effect of cross-fostering on the eradication of the pathogens. Previous studies of the prevalence of H. hepaticus showed high variation [3,7,10,26], and there have been few studies of the prevalences of MNV and P. carinii. Thus, it is difficult to confirm whether the prevalences of the infected mice in our facility are high or low compared to those of previous studies.…”

The Family Helicobacteraceae

“…Surveys of experimental and wild rodent species have shown that their intestinal mucosa is commonly colonized with one or more of the EHS. The organisms commonly found include H. bilis, H. ganmani, H. hepaticus, H. mastomyrinus, H. muridarum, H. rodentium, H. trogontum and H. typhlonius (Zenner 1999;Goto et al 2000;Nilsson et al 2004;Bohr et al 2006;Comunian et al 2006;Johansson et al 2006;Taylor et al 2007;Wasimuddin et al 2012). There is little evidence to support a pathogenic role for these organisms but rather they form part of the normal intestinal microbiota in immunocompetent animals.…”