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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 and the time of its publication because new sequences are continually being submitted to databases. Here we report the presence of helicobacter in commercially bred mice supposedly free of this infection. Furthermore, three out of six 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, U.R., Primus, A., Zagoura, A., Glasbrenner, B., Wex, T., Malfertheiner, P., 2002. A group-specific PCR assay for the detection of Helicobacteraceae in human gut. Helicobacter 7, 378–383] and then cloning and sequencing their products, we detected the H. hepaticus used in the study that three commercial laboratories failed to detect. We think these assays together could detect all the currently known species of helicobacter and hopefully the new ones as well. In addition, 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.

Helicobacter infections of laboratory animals may influence the results of in vivo experiments, necessitating diagnostic methods that are specific, sensitive and rapid. Polymerase chain reaction (PCR) is currently the preferred diagnostic tool for detecting Helicobacter infections in mice; however, detection ability may vary considerably among laboratories. Nine commercial and academic European labs participated in a 3-year ring study that was designed to explore this problem. The authors sought to identify which PCR methods were used for detection of murine Helicobacter spp. in fecal pellets and to compare the sensitivity, specificity and reproducibility of these methods. The study consisted of four rounds in which labs tested mouse fecal samples spiked with H. bilis, H. hepaticus or H. muridarum. The first round showed differences of up to 3 logs in detection sensitivity. Over the course of the study, sensitivity, specificity and reproducibility of PCR results in all labs improved substantially. By the study's conclusion, diagnostic ability in all labs was sufficient to reliably detect Helicobacter in naturally infected mice.