a1 Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3150 Rampart Road, Fort Collins, Colorado 80521, USA
To date no experimental infection studies have been conducted in laboratory mice using Mus spp. bartonella strains. Therefore we designed a study to evaluate the in vivo infection characteristics of 2 Bartonella tribocorum strains from wild Mus spp. in laboratory mice with the aim of developing a mouse model that reproduces characteristics of naturally acquired bartonella infections in rodents. Groups of outbred CD1 female mice were subcutaneously inoculated with low doses of 2 mouse bartonella strains (10, 100, and 1000 bacteria/mouse). Blood was collected weekly for 27 weeks to evaluate bacteraemia kinetics in infected mice. Mouse urine collected during weeks 3–6 post-inoculation was also tested for viable bacteria to determine whether urine might serve as a source of bacterial transmission. Mice were susceptible to infection with both strains. Bacteraemias in mice lasted up to 25 weeks, sometimes with abacteraemic intervals, and achieved levels up to 107 cfu/ml of blood. Temporal lags in bacteraemia onset of up to 19 weeks in length were noted at different inoculum doses. No viable bacteria were detected in mouse urine. Bacteraemic mice displayed characteristics of infection similar to those observed in natural rodent hosts during longitudinal field studies. This mouse model of persistent bacteraemia should be suitable for a variety of experimental uses.
(Received January 09 2012)
(Revised April 29 2012)
(Revised July 15 2012)
(Accepted July 16 2012)
(Online publication September 03 2012)