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.
Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following symptoms: pain, impaired eyesight, photophobia, red eye and a 'gritty' sensation.
Mediastinitis is inflammation of the tissues in the mid-chest, or mediastinum. It can be either acute or chronic. It is thought to be due to four different etiologies:
Micrococcus is a genus of bacteria in the Micrococcaceae family. Micrococcus occurs in a wide range of environments, including water, dust, and soil. Micrococci have Gram-positive spherical cells ranging from about 0.5 to 3 micrometers in diameter and typically appear in tetrads. They are catalase positive, oxidase positive, indole negative and citrate negative. Micrococcus has a substantial cell wall, which may comprise as much as 50% of the cell mass. The genome of Micrococcus is rich in guanine and cytosine (GC), typically exhibiting 65 to 75% GC-content. Micrococci often carry plasmids that provide the organism with useful traits.
Alcaligenes is a genus of Gram-negative, aerobic, rod-shaped bacteria in the order of Burkholderiales.
Eikenella corrodens is a Gram-negative facultative anaerobic bacillus that can cause severe invasive disease in humans. It was first identified by M. Eiken in 1958, who called it Bacteroides corrodens. E. corrodens is a rare pericarditis associated pathogen. It is a fastidious, slow growing, human commensal bacillus, capable of acting as an opportunistic pathogen and causing abscesses in several anatomical sites, including the liver, lung, spleen, and submandibular region. E. corrodens could independently cause serious infection in both immunocompetent and immunocompromised hosts.
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.
Mycobacteroides abscessus is a species of rapidly growing, multidrug-resistant, nontuberculous mycobacteria (NTM) that is a common soil and water contaminant. Although M. abscessus most commonly causes chronic lung infection and skin and soft tissue infection (SSTI), it can also cause infection in almost all human organs, mostly in patients with suppressed immune systems. Amongst NTM species responsible for disease, infection caused by M. abscessus complex are more difficult to treat due to antimicrobial drug resistance.
Ralstonia is a genus of bacteria, previously included in the genus Pseudomonas. It is named after the American bacteriologist Ericka Ralston. Ericka Ralston was born Ericka Barrett in 1944 in Saratoga, California, and died in 2015 in Sebastopol, California. While in graduate school at the University of California at Berkeley, she identified 20 strains of Pseudomonas which formed a phenotypical homologous group, and named them Pseudomonas pickettii, after M.J. Pickett in the Department of Bacteriology at the University of California at Los Angeles, from whom she had received the strains. Later, P. pickettii was transferred to the new genus Ralstonia, along with several other species. She continued her research into bacterial pathogenesis under the name of Ericka Barrett while a professor of microbiology at the University of California at Davis from 1977 until her retirement in 1996.
Arcanobacterium haemolyticum is a species of bacteria classified as a gram-positive bacillus. It is catalase-negative, facultative anaerobic, beta-hemolytic, and not motile. It has been known to cause head and neck infections, pharyngitis, and sinusitis.
Rothia kristinae is a Gram positive bacterium. R. kristinae is a common human skin organism, but can cause opportunistic infections in humans.
Fannyhessea vaginae is a species of bacteria in the family Atopobiaceae. It is a facultative anaerobic, Gram-positive rod-shaped or elliptical coccobacillus found as single elements or in pairs or short chains. It is typically isolated from 80% of women with bacterial vaginosis and it is implicated in treatment failures. Invasive infections such as bacteremia have been reported.
Actinotignum schaalii is a bacterium first isolated from human blood cultures. Its type strain is CCUG 27420. It is a Gram-positive, facultative anaerobic coccoid rod, considered a human pathogen.
Rothia mucilaginosa is a Gram-positive, coagulase-negative, encapsulated, non-spore-forming and non-motile coccus, present in clusters, tetrads or pairs that is a part of the normal oropharyngeal flora. Belonging to the family Micrococcaceae, it was first isolated from the mucous membrane of the cheek and gingiva. It is an oral commensal, that has been linked to causing severe bacteremia in immunocompromised patients. This bacterium has also been shown to form biofilms, similar to that of Pseudomonas aeruginosa. R. mucilaginosa is a cohabitant in the lower airways of patients with chronic lung diseases such as bronchiectasis, however has been shown to elicit anti-inflammatory effects.
Bergeyella zoohelcum is a Gram-negative, rod-shaped, aerobic and non-motile bacterium from the genus of Bergeyella which occurs in the upper respiratory tract of dogs and cats Bergeyella zoohelcum can cause respiratory disease in cats. Bergeyella zoohelcum can cause infections after dog bites.
Kocuria rosea is a gram-positive bacteria that is catalase-positive and oxidase-positive. It has a coccus shape that occurs in the tetrad arrangement and is a strict aerobe that grows best from 25 to 37 °C. K. rosea has also been found to cause urinary tract infections in people with weakened immune systems.
Phytobacter is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from wild rice in China, but also includes a number of isolates obtained during a 2013 multi-state sepsis outbreak in Brazil and, retrospectively, several clinical strains isolated in the 1970s in the United States that are still available in culture collections, which originally were grouped into Brenner's Biotype XII of the Erwinia herbicola-Enterobacter agglomerans-Complex (EEC). Standard biochemical evaluation panels are lacking Phytobacter spp. from their database, thus often leading to misidentifications with other Enterobacterales species, especially Pantoea agglomerans. Clinical isolates of the species have been identified as an important source of extended-spectrum β-lactamase and carbapenem-resistance genes, which are usually mediated by genetic mobile elements. Strong protection of co-infecting sensitive bacteria has also been reported. Bacteria belonging to this genus are not pigmented, chemoorganotrophic and able to fix nitrogen. They are lactose fermenting, cytochrome-oxidase negative and catalase positive. Glucose is fermented with the production of gas. Colonies growing on MacConkey agar (MAC) are circular, convex and smooth with non-entire margins and a usually elevated center. Three species are currently validly included in the genus Phytobacter, which is still included within the Kosakonia clade in the lately reviewed family of Enterobacteriaceae. The incorporation of a fourth species, Phytobacter massiliensis, has recently been proposed via the unification of the genera Metakosakonia and Phytobacter.
Christensenella hongkongensis is a species of clinically relevant gram-positive coccobacilli, first isolated from patients in Hong Kong and Canada in 2006. Although the species remains relatively rare, it has a high mortality rate of up to 50%. Christensenella is thought to be broadly distributed globally, as it has been isolated from patient blood cultures around the world including Hong Kong, South Korea, New Zealand, Canada, Sweden, France and Italy. Fewer than 15 cases of C. hongkongensis have been observed worldwide.
Kocuria varians is a gram-positive species of bacteria in the genus Kocuria. It has been isolated from milk, meat, skin, soil, and beach sand. It is 0.9 to 1.5 micrometers in diameter, and occurs in clusters, which can be up to 4 millimeters in diameter and are yellow. It is known to cause ocular infections, brain abscesses, and endophthalmitis.
Neisseria animaloris, formerly named CDC group EF-4a, is a gram-negative coccoid rod. The bacterium is a commensal of the upper respiratory tract of cats and dogs, and they may cause pulmonary infections in cat. In humans Neisseria animaloris have been reported to cause wound infection after animal bites but also chronic otitis media, bacteremia and endophtalmitis.
