摘要：The mean faecal concentration of Enterobacteriaceae in SPF rats (with an original mouse flora) was log10, 7.4/g faeces, while the mean concentration in conventional rats was log10 6.4/g faeces. The level of Enterobacteriaceae in SPF rats essentially did not change after placing the animals in a conventional environment, while the number of biotypes of Enterobacteriaceae increased from three to five. Giving SPF rats orally intestinal contents from conventional rats has no influence on the level of faecal Enterobacteriaceae and the number of biotypes. Immunosuppression with cyclophosphamide and X-irradiation did not change the concentration of faecal Enterobacteriaeeae, though the number of biotypes increased by a factor two to three in three groups of rats.Keywords: Enterobacteriaceae; Rat; Faeces; Biotypes.
