Campylobacters and impaired fetal development in mice

Intravenous injection of eight human strains of Campylobacter fetus ss fetus and Campylobacter jejuni into mice at various stages of pregnancy demonstrated significant strain differences in ability to affect implantation of the fertilised ovum and to cause resorption of the mouse fetus. Implantation was significantly impaired when C. fetus ss fetus was injected intravenously on day 2 of pregnancy, but no effect was observed in mice receiving C. jejuni. On day 6 of pregnancy, before the development of placental circulation, both C. fetus ss fetus and C. jejuni impaired fetal growth; one strain of C. jejuni had a greater effect than others of the same species. In animals inoculated on day 13 of pregnancy, after the development of placental circulation, six of the eight campylobacter strains caused resorption of the mouse embryos. A similar effect on the embryos was observed after injection of heat-killed organisms, and endotoxin-like substances may have been responsible. It is also suggested that factors other than endotoxin-like substances have a deleterious effect on embryonic growth.