A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.

A genus of gram-negative, aerobic, coccoid bacteria whose organisms are part of the normal flora of the oropharynx, nasopharynx, and genitourinary tract. Some species are primary pathogens for humans.

A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.

Infections with bacteria of the species NEISSERIA MENINGITIDIS.

Strains of Neisseria meningitidis which are the most common ones causing infections or disease in infants. Serogroup B strains are isolated most frequently in sporadic cases, and are less common in outbreaks and epidemics.

A fulminant infection of the meninges and subarachnoid fluid by the bacterium NEISSERIA MENINGITIDIS, producing diffuse inflammation and peri-meningeal venous thromboses. Clinical manifestations include FEVER, nuchal rigidity, SEIZURES, severe HEADACHE, petechial rash, stupor, focal neurologic deficits, HYDROCEPHALUS, and COMA. The organism is usually transmitted via nasopharyngeal secretions and is a leading cause of meningitis in children and young adults. Organisms from Neisseria meningitidis serogroups A, B, C, Y, and W-135 have been reported to cause meningitis. (From Adams et al., Principles of Neurology, 6th ed, pp689-701; Curr Opin Pediatr 1998 Feb;10(1):13-8)

Strains of Neisseria meningitidis found mostly in Africa.

Strains of Neisseria meningitidis responsible for most sporadic cases in teenagers and almost all outbreaks of disease in this age group. These strains are less common in infants.

Strains of Neisseria meningitidis responsible for most outbreaks of meningococcal disease in Western Europe and the United States in the first half of the 20th century. They continue to be a major cause of disease in Asia and Africa, and especially localized epidemics in Sub-Sahara Africa.

Strains of Neisseria meningitidis which, in the United States, causes disease in mostly adults and the elderly. Serogroup Y strains are associated with PNEUMONIA.

A species of gram-negative, aerobic BACTERIA commonly found in the NASOPHARYNX of infants and children, but rarely pathogenic. It is the only species to produce acid from LACTOSE.

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

Vaccines or candidate vaccines used to prevent infection with NEISSERIA MENINGITIDIS.

Process of determining and distinguishing species of bacteria or viruses based on antigens they share.

Proteins isolated from the outer membrane of Gram-negative bacteria.

Proteins found in any species of bacterium.

Porins are protein molecules that were originally found in the outer membrane of GRAM-NEGATIVE BACTERIA and that form multi-meric channels for the passive DIFFUSION of WATER; IONS; or other small molecules. Porins are present in bacterial CELL WALLS, as well as in plant, fungal, mammalian and other vertebrate CELL MEMBRANES and MITOCHONDRIAL MEMBRANES.

An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides.

Acute infectious disease characterized by primary invasion of the urogenital tract. The etiologic agent, NEISSERIA GONORRHOEAE, was isolated by Neisser in 1879.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.

A class of carrier proteins that bind to TRANSFERRIN. Many strains of pathogenic bacteria utilize transferrin-binding proteins to acquire their supply of iron from serum.

Substances elaborated by bacteria that have antigenic activity.

Polysaccharides found in bacteria and in capsules thereof.

The condition of harboring an infective organism without manifesting symptoms of infection. The organism must be readily transmissible to another susceptible host.

A subtype of bacterial transferrin-binding protein found in bacteria. It forms a cell surface receptor complex with TRANSFERRIN-BINDING PROTEIN A.

Infections with bacteria of the family NEISSERIACEAE.

Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.

The functional hereditary units of BACTERIA.