Streptococcus pneumoniae is a leading cause of bacterial pneumonia worldwide. Given the critical role of dendritic cells (DCs) in regulating and modulating the immune response to pathogens, we investigated here the role of DCs in S. pneumoniae lung infections. Using a well-established transgenic mouse line which allows the conditional transient depletion of DCs, we showed that ablation of DCs r...

Streptococcus pneumoniae is a Gram-positive, extracellular bacterium that is responsible for significant mortality and morbidity worldwide. Pneumolysin (PLY), a cytolysin produced by all clinical isolates of the pneumococcus, is one of the most important virulence factors of this pathogen. We have previously reported that PLY is an essential factor for activation of caspase-1 and consequent sec...

INTRODUCTION Streptococcus pneumoniae, a leading cause of morbidity and mortality in the United States, is the most common cause of community-acquired pneumonia, bacterial meningitis, acute otitis media, and bacteremia. 1 Pneumococcal infections are among the most common reasons for acute-care office visits and hospitalization, and cause an estimated 40,000 deaths annually in the United States....

BACKGROUND A better understanding of the epidemiology of nasopharyngeal carriage of Streptococcus pneumoniae is important to assess the impact of vaccination and the pathogenesis of pneumococcal disease. We compared the recovery of S. pneumoniae from nylon flocked, Dacron and rayon swabs. METHODS The recovery of S. pneumoniae from mocked specimens using flocked, Dacron and rayon swabs were co...

Streptococcus pneumoniae is a leading cause of pneumonia and one of the most common causes of death globally. The impact of S. pneumoniae on host molecular processes that lead to detrimental pulmonary consequences is not fully understood. Here, we show that S. pneumoniae induces toxic DNA double-strand breaks (DSBs) in human alveolar epithelial cells, as indicated by ataxia telangiectasia mutat...

OBJECTIVE To determine the epidemiology of Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae invasive infections in hospitalized Guatemalan children. This is an important issue since Hib vaccine has not been incorporated into the routine immunization program in Guatemala and information from hospital records in 1995 indicated a low incidence of Hib and S. pneumoniae as causes of ...

Little is known regarding the role of Toll-like receptors (TLRs) in regulating protein- and polysaccharide-specific immunoglobulin (Ig) isotype production in response to an in vivo challenge with an extracellular bacterium. In this report we demonstrate that MyD88(-/-), but not TLR2(-/-), mice are markedly defective in their induction of multiple splenic proinflammatory cytokine- and chemokine-...

The optochin susceptibility test is a key method for differentiating Streptococcus pneumoniae from other -hemolytic streptococci; however, optochin-resistant (Opt) S. pneumoniae have been reported in the last two decades. In this study, we investigated the isolation frequency of Opt S. pneumoniae in the North Kyushu area of Japan, and biochemically and genetically characterized Opt S. pneumoni...

Nasal colonization by Staphylococcus aureus is a major predisposing factor for subsequent infection. Recent reports of increased S. aureus colonization among children receiving pneumococcal vaccine implicate Streptococcus pneumoniae as an important competitor for the same niche. Since S. pneumoniae uses H2O2 to kill competing bacteria, we hypothesized that oxidant defense could play a significa...

Streptococcus pneumoniae is one of the major causative agents of pneumonia, sepsis, meningitis and other morbidities. In spite of its heavy disease burden, surprisingly little is known about the mechanisms involved in the switch of life style, from commensal colonizer of the nasopharynx to invasive pathogen. In vitro experiments, and mouse models have shown that S. pneumoniae can be internalize...