Mouse subcutaneous chamber model for in vivo growth of Haemophilus ducreyi

The ability of Haemophilus ducreyi, the causative agent of chancroid, to grow in subcutaneous chambers implanted in mice was studied. All seven H. ducreyi strains tested were able to maintain a long-term infection in ICR mice; one mouse remained infected with strain Hd175 for more than 4 months. Growth curves obtained following the removal of chamber fluid at various time points from infected mice demonstrated that H. ducreyi was growing during the course of the infection. In addition, all three mouse strains tested (ICR, CBA and BALB/c) were able to maintain long-term H. ducreyi infections. This model will be valuable in studying the effects of in vivo growth on the antigenic composition of H. ducreyi as well as for the identification of virulence factors.