Characterization of Pneumococcal Genes Involved in Bloodstream Invasion in a Mouse Model. Streptococcus pneumoniae

Streptococcus pneumoniae (the pneumococcus) account for significant morbidity and mortality worldwide, causing life-threatening diseases such as pneumonia, bacteremia and meningitis. In this study, we used microarray analysis to compare gene expression patterns of either serotype 4 or serotype 6A pneumococci in the nasopharynx and blood of mice, as a model to identify genes involved in invasion of blood in the context of occult bacteremia in humans. Overall design: Microarray experiments were performed on whole genome S. pneumoniae PCR arrays obtained from the Bacterial Microarray Group at St George's Hospital Medical School, London (http://bugs.sghms.ac.uk/). The array was designed using TIGR4 base strain annotation and extra target genes from strain R6. Pair-wise comparisons were made between the nasopharynx and blood RNA samples labeled with either Alexa Fluor 546 or Alexa Fluor 647 dye from the 48, 72 and 96 h time points.