Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is their cell envelope, which consists of a thin peptidoglycan cell wall sandwiched between an inner (cytoplasmic) membrane and an outer membrane. These bacteria are found in all environments that support life on Earth.
Neisseria is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, N. meningitidis and N. gonorrhoeae.
Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic member of the genus Streptococcus. S. pneumoniae cells are usually found in pairs (diplococci) and do not form spores and are non motile. As a significant human pathogenic bacterium S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century, and is the subject of many humoral immunity studies.
Haemophilus influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.
Klebsiella is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule.
An overwhelming post-splenectomy infection (OPSI) is a rare but rapidly fatal infection occurring in individuals following removal of the spleen. The infections are typically characterized by either meningitis or sepsis, and are caused by encapsulated organisms including Streptococcus pneumoniae. It is a medical emergency and requires immediate treatment. Death has been reported to occur within 12 hours.
Bacterial pneumonia is a type of pneumonia caused by bacterial infection.
A conjugate vaccine is a type of subunit vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen.
A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epidemiologic classification of organisms to a level below the species. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.
Neisseria meningitidis, often referred to as the meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically a diplococcus because of its tendency to form pairs.
Brazilian purpuric fever (BPF) is an illness of children caused by the bacterium Haemophilus influenzae biogroup aegyptius which is ultimately fatal due to sepsis. BPF was first recognized in the São Paulo state of Brazil in 1984. At this time, young children between the ages of 3 months and 10 years were contracting a strange illness which was characterized by high fever and purpuric lesions on the body. These cases were all fatal, and originally thought to be due to meningitis. It was not until the autopsies were conducted that the cause of these deaths was confirmed to be infection by H. influenzae aegyptius. Although BPF was thought to be confined to Brazil, other cases occurred in Australia and the United States during 1984–1990.
The quellung reaction, also called the Neufeld reaction, is a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Bacillus anthracis, Haemophilus influenzae, Escherichia coli, and Salmonella. The antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge.
Cefodizime is a 3rd generation cephalosporin antibiotic with broad spectrum activity against aerobic gram positive and gram negative bacteria. Clinically, it has been shown to be effective against upper and lower respiratory tract infections, urinary tract infections, and gonorrhea. Cefodizime is a bactericidal antibiotic that targets penicillin-binding proteins (PBPs) 1A/B, 2, and 3 resulting in the eventual death of the bacterial cell. In vivo experimental models of infection showed that bacterial clearance by this drug is at least as effective compared with other 3rd generation cephalosporins. It has similar adverse effect profile to other 3rd generation cephalosporins as well, mainly being limited to gastrointestinal or dermatological side effects.
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.
Pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae.
Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria.
Pneumonia can be classified in several ways, most commonly by where it was acquired, but may also by the area of lung affected or by the causative organism. There is also a combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease or systemic disease and whether the person has recently been hospitalized.
IgA protease is an enzyme. This enzyme catalyses the following chemical reaction[reaction equation needed]
Dan M. Granoff is an infectious disease physician-scientist who was named the 2014 Maurice Hilleman/Merck Laureate by the American Society for Microbiology for outstanding contributions to vaccine discovery and development. Beginning in 2011, Granoff held the Clorox Foundation Endowed Chair and was director of the Center of Immunobiology and Vaccine Development at Children's Hospital Oakland Research Institute. His work increased understanding of basic mechanisms of human immunity to encapsulated bacteria, and furthered development of vaccines against Haemophilus influenzae type B (Hib) and Neisseria meningitidis.
