Capsule Type of Streptococcus pneumoniae Determines Growth Phenotype

• DOI: 10.1371/journal.ppat.1002574
• Publication Date: 2012-03-08T21:56:37Z
• Authors: Lucy J. Hathaway; Silvio D. Brugger; Brigitte Morand; Mathieu Bangert; Jeannine U. Rotze...; Christoph Hauser; Werner A. Graber; Suzanna Gore; Aras Kadioglu; Kathrin Mühlemann
• Keywords: Capsule; Carriage; Bacterial capsule

The polysaccharide capsule of Streptococcus pneumoniae defines over ninety serotypes, which differ in their carriage prevalence and invasiveness for poorly understood reasons. Recently, an inverse correlation between oligosaccharide structure a given has been described. Our previous work suggested link serotype growth vitro. Here we investigate whether production interferes with vitro this predicts vivo. Eighty-one switch mutants were constructed representing nine different five low (4, 7F, 14, 15, 18C) four high (6B, 9V, 19F, 23F). Growth (length lag phase, maximum optical density) wildtype strains, nontypeable was studied nutrient-restricted Lacks medium (MLM) rich undefined brain heart infusion broth supplemented 5% foetal calf serum (BHI+FCS). In MLM phenotype depended on, transferred with, operon type. Colonization efficiency mouse nasopharynx also Capsule interfered growth, correlated inversely serotype-specific prevalence. Serotypes better higher produced thicker capsules (by electron microscopy, FITC-dextran exclusion assays HPLC) than serotypes delayed However, expression cpsA, the first gene, quantitative RT-PCR) thickness. Energy spent (incorporation H3-glucose) relative to amount Experiments BHI+FCS showed overall bacterial more differences no longer apparent. Production S. nutrient-limiting conditions probably by competition energy against central metabolism. Serotype-specific nasopharyngeal vivo is predicted phenotype.