The study of the structure, growth, function, genetics, and reproduction of bacteria, and BACTERIAL INFECTIONS.

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.

The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.

A genus of gram-negative, strictly aerobic, non-spore forming rods. Soil and water are regarded as the natural habitat. They are sometimes isolated from a hospital environment and humans.

The study of microorganisms such as fungi, bacteria, algae, archaea, and viruses.

Acute or chronic inflammation of tissues surrounding the apical portion of a tooth, associated with the collection of pus, resulting from infection following pulp infection through a carious lesion or as a result of an injury causing pulp necrosis. (Dorland, 27th ed)

Techniques used in studying bacteria.

Infections by bacteria, general or unspecified.

A genus of gram-positive, anaerobic, coccoid bacteria that is part of the normal flora of humans. Its organisms are opportunistic pathogens causing bacteremias and soft tissue infections.

Time period from 1801 through 1900 of the common era.

Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection.

Solitary or multiple collections of PUS within the lung parenchyma as a result of infection by bacteria, protozoa, or other agents.

Localized circumscribed purulent area of inflammation in the periodontal tissue. It is a derivative of marginal periodontitis and commonly associated with suprabony and infrabony pockets and interradicular involvements, in contrast to periapical abscess which is attributable to pulp necrosis.

A genus of gram-negative, anaerobic, rod-shaped bacteria found in cavities of humans and other animals. No endospores are formed. Some species are pathogenic and occur in various purulent or gangrenous infections.

The prevention of access by infecting organisms to the locus of potential infection.

Facilities equipped to carry out investigative procedures.

Material coughed up from the lungs and expectorated via the mouth. It contains MUCUS, cellular debris, and microorganisms. It may also contain blood or pus.

A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.

A genus of gram-positive, anaerobic bacteria whose organisms divide in three perpendicular planes and occur in packets of eight or more cells. It has been isolated from soil, grains, and clinical specimens.

A genus of gram-positive, spherical bacteria found in soils and fresh water, and frequently on the skin of man and other animals.

Inflammation of gum tissue (GINGIVA) without loss of connective tissue.

A genus of gram-negative, anaerobic cocci parasitic in the mouth and in the intestinal and respiratory tracts of man and other animals.

A family of gram-negative bacteria found primarily in the intestinal tracts and mucous membranes of warm-blooded animals. Its organisms are sometimes pathogenic.

A genus of gram-negative, anaerobic, nonsporeforming, nonmotile rods. Organisms of this genus had originally been classified as members of the BACTEROIDES genus but overwhelming biochemical and chemical findings in 1990 indicated the need to separate them from other Bacteroides species, and hence, this new genus was established.

Substances that reduce the growth or reproduction of BACTERIA.

A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the intestines of humans and a wide variety of animals, as well as in manure, soil, and polluted waters. Its species are pathogenic, causing urinary tract infections and are also considered secondary invaders, causing septic lesions at other sites of the body.

A genus of gram-positive, facultatively anaerobic, coccoid bacteria. Its organisms occur singly, in pairs, and in tetrads and characteristically divide in more than one plane to form irregular clusters. Natural populations of Staphylococcus are found on the skin and mucous membranes of warm-blooded animals. Some species are opportunistic pathogens of humans and animals.

Life or metabolic reactions occurring in an environment containing oxygen.

Hospital facilities equipped to carry out investigative procedures.

The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

Death and putrefaction of tissue usually due to a loss of blood supply.

A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that utilizes citrate as a sole carbon source. It is pathogenic for humans, causing enteric fevers, gastroenteritis, and bacteremia. Food poisoning is the most common clinical manifestation. Organisms within this genus are separated on the basis of antigenic characteristics, sugar fermentation patterns, and bacteriophage susceptibility.

A genus of asporogenous bacteria isolated from soil that displays a distinctive rod-coccus growth cycle.

A genus of asporogenous bacteria that is widely distributed in nature. Its organisms appear as straight to slightly curved rods and are known to be human and animal parasites and pathogens.

A family of gram-negative, facultatively anaerobic, rod-shaped bacteria that do not form endospores. Its organisms are distributed worldwide with some being saprophytes and others being plant and animal parasites. Many species are of considerable economic importance due to their pathogenic effects on agriculture and livestock.

Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.

Time period from 1901 through 2000 of the common era.

Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.

A genus of gram-negative, anaerobic, rod-shaped bacteria. Its organisms are normal inhabitants of the oral, respiratory, intestinal, and urogenital cavities of humans, animals, and insects. Some species may be pathogenic.

Procedures for collecting, preserving, and transporting of specimens sufficiently stable to provide accurate and precise results suitable for clinical interpretation.

"The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.

The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.

Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).

Bacteria which retain the crystal violet stain when treated by Gram's method.

Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.

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