Differential persistence of Burkholderia multivorans and Burkholderia cenocepacia in the mouse

Karen Ka Yee Chu
Members of the Burkholderia cepacia complex (BCC) of organisms are important opportunistic pathogens, particularly in cystic fibrosis (CF) patients. Infection with members of the BCC is associated with poor prognosis. There is speculation that the BCC are intracellular pathogens, surviving and growing inside epithelial cells or professional phagocytes. B. cenocepacia strains are the predominant Canadian BCC-CF pathogens in that members of this species cause the most numerous infections, are the
more » ... most highly transmissible, and are associated with the highest rates of systemic illness and mortality. B. multivorans infections, though prevalent, are associated with lower rates of transmissibility and mortality. The apparent differential pathogenic ability of these two species has not yet been studied in detail in any model systems. The purpose of these studies was to determine the mechanisms of differential pathogenicity between these two related bacterial species. Three different models of murine infection were used to evaluate B. multivorans and B. cenocepacia infections: an intraperitoneal model of systemic infection, a leukopenic model of pulmonary infection, and an immunocompetent model of pulmonary infection. Differences in the infection kinetics of B. multivorans and B. cenocepacia were observed in all three systems. These potential differences in the pathogenic capability of B. multivorans and B. cenocepacia were further characterized in the immunocompetent model of infection. In the immunocompetent model of intranasal infection, mice were challenged with a 7 single dose of bacteria in stationary phase that had been adjusted to 10 CFU. B. cenocepacia strain C6433 caused a greater degree of systemic illness in mice despite speedy clearance from the lung; persistent B. multivorans strain C5568 caused no systemic illness in mice. The differential infection kinetics and host toxicity demonstrated in this model mirrored observations in a leukopenic model of pulmonary infection, as well as an [...]
doi:10.14288/1.0091763 fatcat:lu2xo4upardn7cj3w4z5yplb7q