Bloodstream infections (BSIs) are infections of blood caused by blood-borne pathogens. Blood is normally a sterile environment, so the detection of microbes in the blood is always abnormal. A bloodstream infection is different from sepsis, which is characterized by severe inflammatory or immune responses of the host organism to pathogens.
In prokaryote nomenclature, Candidatus is used to name prokaryotic taxa that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S ribosomal RNA sequencing or metagenomics, provide much information about the analyzed organisms and thus allow to identify and characterize individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in in vitro study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity.
Enterobacter is a genus of common Gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacteria of the family Enterobacteriaceae. Cultures are found in soil, water, sewage, feces and gut environments. It is the type genus of the order Enterobacterales. Several strains of these bacteria are pathogenic and cause opportunistic infections in immunocompromised hosts and in those who are on mechanical ventilation. The urinary and respiratory tracts are the most common sites of infection. The genus Enterobacter is a member of the coliform group of bacteria. It does not belong to the fecal coliforms group of bacteria, unlike Escherichia coli, because it is incapable of growth at 44.5 °C in the presence of bile salts. Some of them show quorum sensing properties.
Moraxella catarrhalis is a fastidious, nonmotile, Gram-negative, aerobic, oxidase-positive diplococcus that can cause infections of the respiratory system, middle ear, eye, central nervous system, and joints of humans. It causes the infection of the host cell by sticking to the host cell using trimeric autotransporter adhesins.
Streptococcus bovis is a species of Gram-positive bacteria that in humans is associated with urinary tract infections, endocarditis, sepsis, and colorectal cancer. S. gallolyticus is commonly found in the alimentary tract of cattle, sheep, and other ruminants, and may cause ruminal acidosis or feedlot bloat. It is also associated with spontaneous bacterial peritonitis, a frequent complication occurring in patients affected by cirrhosis. Equivalence with Streptococcus equinus has been contested.
Moraxella is a genus of gram-negative bacteria in the family Moraxellaceae. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli, or as in the case of Moraxella catarrhalis, diplococci in morphology, with asaccharolytic, oxidase-positive, and catalase-positive properties. M. catarrhalis is the clinically most important species under this genus.
Elizabethkingia meningoseptica is a Gram-negative, rod-shaped bacterium widely distributed in nature. It may be normally present in fish and frogs; it may be isolated from chronic infectious states, as in the sputum of cystic fibrosis patients. In 1959, American bacteriologist Elizabeth O. King was studying unclassified bacteria associated with pediatric meningitis at the Centers for Disease Control and Prevention in Atlanta, when she isolated an organism that she named Flavobacterium meningosepticum. In 1994, it was reclassified in the genus Chryseobacterium and renamed Chryseobacterium meningosepticum(chryseos = "golden" in Greek, so Chryseobacterium means a golden/yellow rod similar to Flavobacterium). In 2005, a 16S rRNA phylogenetic tree of Chryseobacteria showed that C. meningosepticum along with C. miricola were close to each other but outside the tree of the rest of the Chryseobacteria and were then placed in a new genus Elizabethkingia named after the original discoverer of F. meningosepticum.
Delftia acidovorans is a Gram-negative, motile, non-sporulating, rod-shaped bacterium known for its ability to biomineralize gold and bioremediation characteristics. It was first isolated from soil in Delft, Netherlands. The bacterium was originally categorized as Pseudomonas acidovorans and Comamonas acidovorans before being reclassified as Delftia acidovorans.
Streptococcus equinus is a Gram-positive, nonhemolytic, nonpathogenic, lactic acid bacterium of the genus Streptococcus. It is the principal Streptococcus found in the alimentary canal of a horse, and makes up the majority of the bacterial flora in horse feces. Equivalence with Streptococcus bovis has been contested.
Tannerella forsythia is an anaerobic, Gram-negative bacterial species of the Bacteroidota phylum. It has been implicated in periodontal diseases and is a member of the red complex of periodontal pathogens. T. forsythia was previously named Bacteroides forsythus and Tannerella forsythensis.
Clostridium innocuum is an anaerobic, non-motile, gram-positive bacterium that reproduces by sporulation. While there are over 130 species of Clostridium, C. innocuum is the third most commonly isolated. Although it is not normally considered an aggressive human pathogen, it has been isolated in some disease processes. C. innocuum and other Clostridium line the oropharynx and gastrointestinal tract, and are considered normal gut flora.
Acinetobacter schindleri is a species of bacteria. It is potentially pathogenic. Its type strain is LUH 5832T.
Psychrobacter is a genus of Gram-negative, osmotolerant, oxidase-positive, psychrophilic or psychrotolerant, aerobic bacteria which belong to the family Moraxellaceae and the class Gammaproteobacteria. The shape is typically cocci or coccobacilli. Some of those bacteria were isolated from humans and can cause humans infections such as endocarditis and peritonitis. This genus of bacteria is able to grow at temperatures between −10 and 42 °C. Rudi Rossau found through DNA-rRNA hybridization analysis that Psychrobacter belongs to the Moraxellaceae. The first species was described by Juni and Heym. Psychrobacter occur in wide range of moist, cold saline habitats, but they also occur in warm and slightly saline habitats.
Psychrobacter phenylpyruvicus is a Gram-negative, catalase- and oxidase-positive, nonmotile bacterium of the genus Psychrobacter, which was isolated from human blood in Belgium. Psychrobacter phenylpyruvicus can cause humans infections such as endocarditis, peritonitis, and fungating lesion of the foot, but those infections caused by this bacterium are rare.
Microlunatus lucidus is a Gram-positive, non-motile, aerobic actinomycete.
Moraxella oblonga is a catalase- and oxidase-positive, Gram-negative bacterium in the genus Moraxella, which was isolated from the oral cavity of a sheep. Alysiella sp. was transferred to M. oblonga.
Moraxella pluranimalium is a Gram-negative, aerobic, catalase- and oxidase-positive, non-spore-forming bacterium in the genus Moraxella, which was isolated from the nasal turbinate of a pig.
Dietzia papillomatosis is a bacterium from the genus Dietzia which has been isolated from the skin scrapings of a patient in the United Kingdom.
Tsukamurella sinensis is a bacterium from the genus of Tsukamurella which has been isolated from a patient from the Queen Mary Hospital in Hong Kong.
Janibacter is a genus of Gram positive, nonmotile, non-sporeforming bacteria. The genus name is derived from the two-faced Roman god Janus, referring to the fact that the cells of the original strain could be rod-shaped or coccoid.
