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Blood is normally sterile. [1] The presence of bacteria in the blood is termed bacteremia, and the presence of fungi is called fungemia. [2] Minor damage to the skin [3] or mucous membranes, which can occur in situations like toothbrushing or defecation, [4] [5] can introduce bacteria into the bloodstream, but this bacteremia is normally transient and is rarely detected in cultures because the ...
The presence of certain bacteria in the blood culture, such as Staphylococcus aureus, Streptococcus pneumoniae, and Escherichia coli almost never represent a contamination of the sample. On the other hand, contamination may be more highly suspected if organisms like Staphylococcus epidermidis or Cutibacterium acnes grow in the blood culture.
This includes whole blood; blood components; and plasma derivatives. Blood components include: red blood cell concentrates or suspensions; platelets produced from whole blood or via apheresis; Granulocyte, plasma; and cryoprecipitate. Some products for topical use, such as serum eye drops, have also been recently classified as blood components. [2]
The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms .
It may be prepared using more conventional techniques as is the case for blood or plasma-derived products and a number of vaccines. Active substance – consisting of entire microorganisms, mammalian cells, nucleic acids, proteinaceous, or polysaccharide components originating from a microbial, animal, human, or plant source.
Endospore-forming bacteria can cause disease; for example, anthrax can be contracted by the inhalation of Bacillus anthracis endospores, and contamination of deep puncture wounds with Clostridium tetani endospores causes tetanus, which, like botulism, is caused by a toxin released by the bacteria that grow from the spores. [99]
Since bacteria ferment carbohydrates in patterns characteristic of their genus and species, the detection of fermentation products is commonly used in bacterial identification. Acids , alcohols and gases are usually detected in these tests when bacteria are grown in selective liquid or solid media.
These chemical signals may include proteins from invading bacteria, clotting system peptides, complement products, and cytokines that have been given off by macrophages located in the tissue near the infection site. [14] Another group of chemical attractants are cytokines that recruit neutrophils and monocytes from the blood. [11]