Streptococcus pneumoniae is an opportunistic pathogen that asymptomatically colonizes the nasopharynx. In susceptible individuals, such as children and the elderly, pneumococci can be aspirated into the lungs resulting in pneumonia, which is followed by disseminated diseases such as otitis media, bacteremia, and meningitis. Due to the high number of individuals colonized with Streptococcus pneumoniae, there is a heavy burden of the disease both socioeconomically and in terms of morbidity and mortality.
The prevailing model of transmission posits that transmission occurs via respiratory droplets, however work in our lab has showed that Streptococcus pneumoniae can survive long periods of desiccation. Upon subsequent rehydration, a proportion of the bacteria were found to remain viable and infectious. Thus bacteria desiccated on surfaces, also referred to as fomites, may serve as an alternate source of infection. We intend to further probe the ability of the bacterium to survive periods of desiccation using a transposon insertion mutagenesis screen to identify genes required for the desiccation tolerance phenotype. This analysis will shed light on this mode of desiccation that is distinct from that caused by sporulation. From the perspective of transmission, it is significant as a possible reservoir of infection. I hope to further describe the mechanism of desiccation tolerance, which may aid in the discovery of new ways to decrease the spread of Streptococcus pneumoniae and thereby decrease the rate of infection.