Effect of Escherichia coli infection of the bovine uterus from the whole animal to the cell

Abstract

Following parturition, contamination of the uterine lumen by bacteria is ubiquitous, and uterine health is impaired in cattle because infection persists in 10% to 15% of animals as endometritis. Endometritis causes infertility for the duration of infection, and subfertility persists even after apparent successful resolution of the disease. Escherichia coli is the pathogenic bacterium most frequently isolated from the post partum uterus, and is associated with increased concentrations of peripheral plasma acute phase proteins and fetid vaginal mucus. The presence of E. coli is also associated with slower growth of the first post partum dominant follicle and perturbed oestradiol secretion. Furthermore, in animals that ovulate the first dominant follicle, the corpus luteum is smaller and secretes less progesterone. The endotoxin lipopolysaccharide (LPS), which is released from E.coli, can pass from the uterine lumen to the peripheral circulation and LPS concentrations are increased in cows with uterine infection. Infusion of E. coli LPS into the uterine lumen suppresses the pre-ovulatory luteinising hormone surge and disrupts ovulation in heifers. In vitro, endometrial explants produce prostaglandins in response to LPS. Addition of LPS or E. coli to stromal or epithelial cells increases cyclooxygenase-2 mRNA expression, and stimulates the production of prostaglandin E 2 and prostaglandin F 2a . Furthermore, uterine and ovarian cells express mRNA of the molecules required for recognition of LPS, Toll-like receptor-4 and CD14. In summary, E. coli is a common cause of infertility involving the perturbation of the hypothalamus, pituitary and ovary in dairy cows.

Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

“…Kendall and others (2009) have suggested that animals with low progesterone values on day 7 are less likely to become pregnant. What is even more important in light of this study with respect to endometritis is the finding of Williams and others (2008) that uterine infection reduces luteal-phase progesterone values. Kendall and others (2009) were unable to improve pregnancy rates in repeat breeders with treatments designed to increase progesterone concentrations (CIDRs or human chorionic gonadotrophin injections) on days 5 or 6 after AI.…”

Parturition to resumption of ovarian cyclicity: comparative aspects of beef and dairy cows

“…Furthermore, in the animals that ovulated, the CL was smaller and produced less progesterone (Figure 6; . Within the uterus E. coli may disrupt the mechanisms of PG-induced luteolysis in cyclic cows and therefore contribute to prolonged luteal phases by switching PG synthesis away from PGF2α towards PGE 2 (Herath et al, 2009;Williams et al, 2008b). These observations show a direct correlation between the presence of uterine pathogens, particularly E. coli, on day 7 postpartum and suboptimal ovarian function for the following 3 weeks.…”

Trueperella pyogenes and Escherichia coli as an etiological factor of endometritis in cows and the susceptibility of these bacteria to selected antibiotics

“…F. necrophorum produces leukotoxin and P. melaninogenicus produces a substance which inhibits phagocytosis, which allows them to inhibit cell-mediated and humoral immunity, or both. It promotes the development of infections, and microorganisms may persist in the uterus for an extended length of time (Miller et al 2007, Williams et al 2008a,b, Sheldon et al 2010.…”