Streptococcus is the dominant bacterial genus in the human oral cavity and a leading cause of infective endocarditis. Streptococcus sanguinis belongs to the mitis group of streptococci and produces hydrogen peroxide (H2O2) by the action of SpxB, a pyruvate oxidase. In this study, we investigated the involvement of SpxB in survival of S. sanguinis in human blood and whether bacterial H2O2 exhibi...

BACKGROUND Influenza pneumonia causes high mortality every year, and pandemic episodes kill millions of people. Influenza-related mortality has been variously ascribed to an ineffective host response that fails to limit viral replication, an excessive host inflammatory response that results in lung injury and impairment of gas exchange, or to bacterial superinfection. We sought to determine whe...

We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rat...

To determine the role of Toll-like receptor 4 (TLR4) in the immune response to pneumonia, C3H/HeJ mice (which display a mutant nonfunctional TLR4) and C3H/HeN wild-type mice were intranasally infected with either Streptococcus pneumoniae (a common gram-positive respiratory pathogen) or Klebsiella pneumoniae (a common gram-negative respiratory pathogen). In cases of pneumococcal pneumonia, TLR4 ...

Bacterial growth and survival in numerous environments are constrained by the action of bacteria-consuming protozoa. Recent findings suggest that bacterial adaptations against protozoan predation might have a significant role in bacterial persistence and diversification. We argue that selective predation has given rise to diverse routes of bacterial defense, including adaptive mechanisms in bac...

To determine the impact of early surgical intervention on long-term survival in patients with infective endocarditis (IE), charts of all patients who had IE from January 1987 through December 1996 were reviewed. A total of 252 patients with definite or possible IE were included. Forty-four patients (17.5%) had early surgery on median hospital day 2 (range, 0-30 days), and 208 patients (82.5%) r...

BACKGROUND/AIMS Gold-standard treatment of spontaneous bacterial peritonitis currently involves 3rd generation cephalosporins. To evaluate the efficacy of ofloxacin in this infection, we compared a combined therapy with intravenous and oral ofloxacin to intravenous cefotaxime. METHODS Thirty cirrhotic patients with spontaneous bacterial peritonitis were assigned to receive either intravenous ...

Gram-negative bacterial pneumonia is a common and dangerous infection with diminishing treatment options due to increasing antibiotic resistance among causal pathogens. The mononuclear phagocyte system is a heterogeneous group of leukocytes composed of tissue-resident macrophages, dendritic cells, and monocyte-derived cells that are critical in defense against pneumonia, but mechanisms that reg...

Fibrinogen can support host antimicrobial containment/clearance mechanisms, yet selected pathogens appear to benefit from host procoagulants to drive bacterial virulence. Here, we explored the hypothesis that host fibrin(ogen), on balance, supports Staphylococcus aureus infection in the context of septicemia. Survival studies following intravenous infection in control and fibrinogen-deficient m...

Meningitis is an inflammation of the membranes that surround the brain and spinal cord, thereby involving the arachnoid, the pia and the cerebrospinal fluid (CSF). It is divided into viral and bacterial meningitis. For different reasons the diagnosis of bacterial meningitis is very important. The examination of CSF samples may provide information about causative microorganism. The sensivity of ...