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HACEK
The HACEK organisms are a group of fastidious Gram-negative bacteria that are an unusual cause of infective endocarditis, which is an inflammation of the heart due to bacterial infection. HACEK is an abbreviation of the initials of the genera of this group of bacteria: ''Haemophilus'', ''Aggregatibacter'' (previously ''Actinobacillus''), '' Cardiobacterium'', ''Eikenella'', ''Kingella''. The HACEK organisms are a normal part of the human microbiota, living in the oral- pharyngeal region. The bacteria were originally grouped because they were thought to be a significant cause of infective endocarditis, but recent research has shown that they are rare and only responsible for 1.4–3.0% of all cases of this disease. Organisms HACEK originally referred to '' Haemophilus parainfluenzae'', '' Haemophilus aphrophilus'', '' Actinobacillus actinomycetemcomitans'', ''Cardiobacterium hominis'', '' Eikenella corrodens'', and ''Kingella kingae''. However, taxonomic rearrangements have changed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infective Endocarditis
Infective endocarditis is an infection of the inner surface of the heart, usually the valves. Signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. Complications may include backward blood flow in the heart, heart failure – the heart struggling to pump a sufficient amount of blood to meet the body's needs, abnormal electrical conduction in the heart, stroke, and kidney failure. The cause is typically a bacterial infection and less commonly a fungal infection. Risk factors include valvular heart disease, including rheumatic disease, congenital heart disease, artificial valves, hemodialysis, intravenous drug use, and electronic pacemakers. The bacteria most commonly involved are streptococci or staphylococci. Diagnosis is suspected based on symptoms and supported by blood cultures or ultrasound of the heart. There is also a noninfective form of endocarditis. The usefulness of antibiotic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiobacterium Hominis
''Cardiobacterium hominis'' is a Gram-negative bacillus (rod-shaped) bacterium commonly grouped with other bacteria into the HACEK group. It is one of several bacteria that is normally present in the mouth and upper part of the respiratory tract such as nose and throat. However, it may also rarely cause endocarditis, an infection of the heart valves. Microbiology ''C. hominis'' is a catalase-negative, oxidase-positive, indole-producing, Gram-negative rod. Its morphology has classically been described as highly pleomorphic and irregularly staining, although homogeneous bacilli with uniform shapes may be seen with the addition of yeast extract. Antibiotic sensitivity Historically, ''C. hominis'' has been sensitive to penicillin and penicillin derivatives such as ampicillin. However, penicillin-resistant strains, including those that produce beta-lactamases, have been described with increasing frequency. Clinical guidelines thus recommend that ''C. hominis'' and other HACEK orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eikenella Corrodens
''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. Microbiology ''Eikenella corrodens'' is a pleomorphic bacillus that sometimes appears coccobacillary and typically creates a depression (or "pit") in the agar on which it is growing. Only half produce the pitting of the agar considered characteristic.. It is slow-growing, facultative, anaerobic and a gram-negative bacillus. It grows in aerobic and anaerobic conditions, but requires a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eikenella
''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. Microbiology ''Eikenella corrodens'' is a pleomorphic bacillus that sometimes appears coccobacillary and typically creates a depression (or "pit") in the agar on which it is growing. Only half produce the pitting of the agar considered characteristic.. It is slow-growing, facultative, anaerobic and a gram-negative bacillus. It grows in aerobic and anaerobic conditions, but requires a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingella
''Kingella'' is a genus of bacteria of the family Neisseriaceae. It belongs to the HACEK group of fastidious Gram-negative bacteria that tend to cause endocarditis. '' Kingella kingae'' is its type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime .... Species As of 2021, five species belong to the genus: *'' Kingella denitrificans'' Snell & Lapage 1976 *'' Kingella kingae'' (Henriksen & Bøvre 1968) Henriksen & Bøvre 1976 *'' Kingella negevensis'' El Houmami ''et al''. 2017 *'' Kingella oralis'' corrig. Dewhirst ''et al''. 1993 *'' Kingella potus'' Lawson ''et al''. 2005 References Neisseriales {{Betaproteobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingella Kingae
''Kingella kingae'' is a species of Gram-negative facultative anaerobic β-hemolytic coccobacilli. First isolated in 1960 by Elizabeth O. King, it was not recognized as a significant cause of infection in young children until the 1990s, when culture techniques had improved enough for it to be recognized. It is best known as a cause of septic arthritis, osteomyelitis, spondylodiscitis, bacteraemia, and endocarditis, and less frequently lower respiratory tract infections and meningitis. There are four species of ''Kingella'': ''K. kingae'', the most common, is part of the bacterial flora of the throat in young children and is transmitted from child to child. When it causes disease, the clinical presentation is often subtle and preceded by a recent history of stomatitis or upper respiratory infection. Other species are ''K. indologenes'', ''K. denitrificans'' (both causing endocarditis) and '' K. oralis'' found in dental plaque. One notable exception is in cases of endocardit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingella Denitrificans
''Kingella'' is a genus of bacteria of the family Neisseriaceae. It belongs to the HACEK group of fastidious Gram-negative bacteria that tend to cause endocarditis. ''Kingella kingae'' is its type species. Species As of 2021, five species belong to the genus: *'' Kingella denitrificans'' Snell & Lapage 1976 *''Kingella kingae ''Kingella kingae'' is a species of Gram-negative facultative anaerobic β-hemolytic coccobacilli. First isolated in 1960 by Elizabeth O. King, it was not recognized as a significant cause of infection in young children until the 1990s, when ...'' (Henriksen & Bøvre 1968) Henriksen & Bøvre 1976 *'' Kingella negevensis'' El Houmami ''et al''. 2017 *'' Kingella oralis'' corrig. Dewhirst ''et al''. 1993 *'' Kingella potus'' Lawson ''et al''. 2005 References Neisseriales {{Betaproteobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiobacterium Valvarum
''Cardiobacterium valvarum'' is a Gram-negative bacteria of the Cardiobacterium genus that can cause infective endocarditis. They belong to the HACEK group of fastidious bacteria that are present in normal oropharyngeal flora that can develop into infective endocarditis. Microbiology The only other identified Cardiobacterium species is ''Cardiobacterium hominis''. Cardiobacterium species are pleomorphic Gram-negative bacteria rod-shaped bacteria that are catalase-negative and oxidase-positive. When compared morphologically, the two Cardiobacterium species are indistinguishable in culture and Gram stain, however, differ in growth patterns. ''C.valvarum'' is more fastidious than ''C. hominis'', and are non-hemolytic. ''C.valvarum'' is also differentiated by the fact that they do not produce indole. Isolates of ''C. valvarum'' show optimal growth by day 3 under standard 5% incubation conditions on 5% sheep blood but scant growth on chocolate agar. Identification Members of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharynx
The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food and air to the esophagus and larynx respectively. The flap of cartilage called the epiglottis stops food from entering the larynx. In humans, the pharynx is part of the digestive system and the conducting zone of the respiratory system. (The conducting zone—which also includes the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles—filters, warms and moistens air and conducts it into the lungs). The human pharynx is conventionally divided into three sections: the nasopharynx, oropharynx, and laryngopharynx. It is also important in vocalization. In humans, two sets of pharyngeal muscles form the pharynx and determine the shape of its lumen. They are arranged as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemophilus Parainfluenzae
''Haemophilus parainfluenzae'' is a species of'' Haemophilus''. It is one of the HACEK organisms. ''H. parainfluenzae'' is an opportunistic pathogen that has been associated with endocarditis, bronchitis, otitis, conjunctivitis, pneumonia, abscesses and genital tract infections. Natural genetic transformation ''H. parainfluenzae'' biotypes I and II are capable of natural genetic transformation. Natural genetic transformation is a bacterial adaptation for DNA transfer. In order for a bacterium to bind, take up and recombine exogenous DNA into its genome it must enter a special physiological state termed natural competence In microbiology, genetics, cell biology, and molecular biology, competence is the ability of a cell to alter its genetics by taking up extracellular ("naked") DNA from its environment in the process called transformation. Competence may be diff .... In ''H. parainfluenzae'', competence is induced during the late stationary phase of growth. Natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
