Streptococcus pneumoniae is a nasopharyngeal commensal that occasionally invades normally sterile sites to cause bloodstream infection and meningitis. Although the pneumococcal population structure and evolutionary genetics are well defined, it is not clear whether pneumococci that cause meningitis are genetically distinct from those that do not. Here, we used whole-genome sequencing of 140 iso...

The pathogenesis of bacteraemia after challenge with one million pneumococci of three isogenic variants was investigated. Sequential analyses of blood samples indicated that most episodes of bacteraemia were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin of invasive disease. With respect to host determinants, results identified novel propert...

The role of serum factors in the phagocytosis of pneumococci was studied employing a spectrophotometric assay which measures reduced nitro blue tetrazolium (NBT) dye. Dye reduction occurs within the phagocyte shortly after bacterial ingestion as measured by the phagocytic index technique and by the uptake of (125)I-pneumococci. Bacteria prepared with gammaG antibody were not phagocytosed unless...

1. Pneumococci in contact with hemoglobin transform this into methemoglobin. This reaction occurs only when the pneumococci are living; it is not induced by the culture fluid or by extracts of the bacteria. 2. The reaction does not occur when hemoglobin is added to an emulsion of washed pneumococci in salt solution. However, if minute traces of dextrose be added to such a mixture, the reaction ...

With a view to obtaining information as to the virulence of pneumococci for human beings a study was made of the pneumococcidal action of normal human serum-leucocyte mixtures for freshly isolated strains of pathogenic pneumococci. It was found that human beings as a group showed well marked pneumococcus destroying power in their blood for all types of organisms studied. Individuals, however, e...

BACKGROUND The role played by pneumolysin and autolysin in pneumococcal meningitis is poorly understood. METHODS A rat model was used to investigate the disease, in which surgical implantation of a cisternal catheter allowed bacterial instillation and cerebrospinal fluid (CSF) sampling. RESULTS CSF infection of rats with wild-type pneumococci caused meningitis within 26 h, whereas isogenic ...

Pneumococcal surface protein A (PspA) and PspC are important virulence factors. Their absence has been shown to allow improved clearance of pneumococci from the blood of mice and to decrease pneumococcal virulence. In the presence of antibody and complement, pneumococci attach to erythrocytes in a process called immune adherence (IA), which facilitates their delivery to, and eventual phagocytos...

The antibacterial activity of RU 64004, a new ketolide, was evaluated against more than 600 bacterial strains and was compared with those of various macrolides and pristinamycin. RU 64004 had good activity against multiresistant pneumococci, whether they were erythromycin A resistant or not, including penicillin-resistant strains. RU 64004 inhibited 90% of pneumococci resistant to erythromycin ...

A pneumococcal infection may be lethal in the absence of overwhelming pulmonary involvement, and death may occur even after the organisms have been killed with antibiotics. The mechanism of death is not understood but may be related to circulating pneumococcal products. For investigating the effects of nonviable pneumococci on several host defense mechanisms, rabbits were injected intravenously...

The important human pathogen Streptococcus pneumoniae was found to absorb factor H, an inhibitor of complement, from human plasma. We identified the gene encoding a novel surface protein, factor H-binding inhibitor of complement (Hic), in the pspC locus of type 3 pneumococci. Unlike PspC proteins in other serotypes, Hic is anchored to the cell wall by means of an LPXTG motif, and the overall se...