Production of ex-germfree rabbits for establishment of specific pathogen-free (SPF) colonies

Nine groups of ex-germfree (Gf) rabbits were produced by inoculation of hys terectomy-derived GF rabbits with various combinations of cecal bacteria is olated from conventional (CV) rabbits in order to establish a barrier-susta ined colony. Six strains of Bacteroides and two strains of Streptococcus is olated from CV rabbits (2 to 3 weeks old) were used for pretreatment. The m ortality of ex-GF rabbits inoculated with the anaerobic growth (CF) on EG o r SM10 plates inoculated with a 10(-5) dilution of cecal contents was 71.4 to 94.4% when given without pretreatment. All ex-GF rabbits pretreated with Bacteroides alone survived, but the mortality of ex-GF rabbits inoculated with Bacteroides plus Streptococcus strains as pretreatment was 20 and 45.4 4%. The mortality of ex-GF rabbits inoculated with only Bacteroides was 43% . AII ex-GF rabbits inoculated with Bacteroides plus anaerobic growth (CF), cecal suspension of ex-GF mice which had been inoculated with cecal suspen sions of CV rabbits (MF) or chloroform-treated cecal suspension (CHF) survi ved, but CHF inoculated ex-GF rabbits were in an unhealthy condition with s light diarrhoea. These data indicate that inoculation with Bacteroides stra ins as pretreatment plus CF or MF was required to convert GF rabbits to the normal state.