Establishment of specific pathogen-free guinea-pig colonies using limited-flora guinea-pigs associated with conventional guinea-pig flora, and monitoring of their cecal flora

Six groups of limited flora (LF) Hartley guinea-pigs were produced by inocu lation of hysterectomy-derived GF guinea-pigs with various combinations of cecal bacteria of conventional (CV) guinea-pigs to determine the effective bacterial cocktails for the establishment of a specific pathogen free (SPF) colony. Bifidobacterium magnum (Bif) isolated from CV guinea-pigs was used for pretreatment. The mortality of LF guinea-pigs inoculated with only Bif was 75%, and that of those inoculated with Bif plus chloroform-treated cec al suspension (CHF) or Bif plus CHF plus 32 isolates from CV guinea-pigs wa s 40 to 66. 7%. These three groups were in an unhealthy condition with muco id enteritis-like diarrhea. However, the mortality of LF guinea-pigs inocul ated with the anaerobic growth on EG plates injected with 10(-5) dilution o f cecal contents (CF) or inoculated with Bif plus CF was 6.3 and 15%, respe ctively. These latter two groups of LF guinea-pigs were transferred to sepa rate barrier rooms and some of the LF guinea-pigs were maintained in isolat ors as a source of intestinal flora for SPF guinea-pigs. The composition of cecal flora of LF guinea-pigs was stable for a long time, and bacteroidace ae and peptococcaceae were maintained as predominant components. The basic composition of the cecal flora of SPF guinea-pigs originated from LF guinea -pigs, which consists mainly of the anaerobic bacteria, was not changed ove r a long period, and the flora composition became similar to that in CV gui nea-pigs. Guinea-pig-specific pathogens from the SPF colonies were not defe cted during experiments.