Evaluation of diagnostic methods for Helicobacter bilis infection in laboratory mice

Disease-susceptible (C3H) and -resistant (B6) immunocompetent and immunodef icient (C3H-scid and B6-rag1) mice were examined up to 10 weeks after inocu lation with Helicobacter bilis (a prototype species of proven virulence). I nfection was monitored weekly by use of fecal culture, polymerase chain rea ction (PCR) nucleic acid amplification, membrane extract enzyme-linked immu nosorbent assay (ELISA), and histologic examination. All mice became infect ed by three to five weeks after inoculation, on the basis of results of cul ture and PCR analysis of feces. The PCR analysis was more sensitive than cu lture at determining infection status, particularly during early infection. None of the mice had evidence of disease by week 10. Immunoglobulin G sero conversion was detectable in C3H mice by week eight and in B6 mice by week nine. Results indicated that culture and PCR analysis are more sensitive th an is membrane extract ELISA serologic testing for detecting early infectio n in individual mice, regardless of genotype or immune status. Results unde rscore the need for improved seroassays for this important group of murine pathogens.