The IN route requires delivering small drops of inoculum into one Selleckchem Fludarabine of the nostrils (total volume of 20 μL), and some of this inoculum could be swallowed rather than inhaled. Signal from the stomach never seemed to last

beyond the 6 hpi time point, suggesting that gastric infections with Y. pestis in these mice are cleared quickly. We also observed that the feces of half of the mice produced detectible signal, indicating that Y. pestis was being shed. This was only observed at very early time points (6 hpi), indicating that bacteria were fully shed from the gastrointestinal tract by 24 hpi. In humans, it has been shown that transmission can occur after ingestion of contaminated food [32]. While mice are coprophagous, it is not know whether a fecal-oral route could be a mechanism for Y. pestis to disperse or infect other individuals. Detecting signal from the tip of the nose also opens the question whether bacteria could be transmitted to other individuals with whom food and water are shared. We do not know whether signal from the LY3039478 stomach or the tip of the nose would still

be present after an aerosol infection, a route that pneumonic plague is assumed to be transmitted in nature. All mice, independent of the presence of signal from the stomach or feces, showed the same progression of infection with comparable levels of signal from the thorax. More importantly, all animals showed signs of disease and mortality at very similar times. This observation suggests that the fraction of the inoculum that may go to the gastrointestinal tract has no effect on the overall pneumonic infection. The low number of mice used during BLI is one of its more important advantages. However, it can also be a disadvantage because of the variability in bacterial load for a specific organ from animal to animal and sudden death, both inherent aspects of plague infections. The differences in the levels of significance from time point to time point when comparing radiance values between the wild type and double mutant Thiazovivin infected animals are due to this high variability of bacterial load and death. Despite these challenges,

we found that BLI is a suitable method for studying dissemination/colonization of Y. pestis in three separate models of plague, and that significant differences in radiance could be detected Reverse transcriptase between wild type and a mutant of modest attenuation using relatively few mice. Conclusions We used BLI to follow bacterial dissemination in mice after SC, ID and IN infections. The dissemination patterns we describe are fully consistent with dissemination and colonization data that has been reported for bubonic and pneumonic plague experiments that describe bacterial burden in specific organs after infection. In addition, we found lower levels of signal from a mutant with established defects in colonization and dissemination in comparison to a wild type strain, indicating that this will be a useful technique for mutational analysis.