|
HACEK Organism
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fastidious Organism
A fastidious organism is any organism that has complex or particular nutritional requirements. In other words, a fastidious organism will only grow when specific nutrients are included in its medium. The more restrictive term fastidious microorganism is used in microbiology to describe microorganisms that will grow only if special nutrients are present in their culture medium. Thus fastidiousness is often practically defined as being difficult to culture, by any method yet tried. Examples An example of a fastidious bacterium is ''Neisseria gonorrhoeae'', which requires blood or hemoglobin and several amino acids and vitamins to grow.Todar, Kenneth''Neisseria gonorrhoeae'', the Gonococcus, and Gonorrhea. Lectures in Microbiology. 2009. Retrieved 2013-03-05. Other examples include ''Campylobacter'' spp. and ''Helicobacter'' spp., which are capnophilic – require elevated CO2 – among other requirements. Fastidious organisms are not inherently "weak"—they can flourish and t ... [...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] |
Endocarditis
Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the surfaces of intracardiac devices. Endocarditis is characterized by lesions, known as '' vegetations'', which is a mass of platelets, fibrin, microcolonies of microorganisms, and scant inflammatory cells. In the subacute form of infective endocarditis, the vegetation may also include a center of granulomatous tissue, which may fibrose or calcify. There are several ways to classify endocarditis. The simplest classification is based on cause: either ''infective'' or ''non-infective'', depending on whether a microorganism is the source of the inflammation or not. Regardless, the diagnosis of endocarditis is based on clinical features, investigations such as an echocardiogram, and blood cultures demonstrating the presence of endocarditis-c ... [...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] |
Haemophilus Segnis
''Aggregatibacter segnis'' is a species of bacteria. ''A. segnis'' can be cultured on chocolate agar Chocolate agar (CHOC) or chocolate blood agar (CBA), is a nonselective, enriched growth medium used for isolation of pathogenic bacteria. It is a variant of the blood agar plate, containing red blood cells that have been lysed by slowly heati .... References Further reading * Pasteurellales Bacteria described in 1976 {{gammaproteobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggregatibacter Paraphrophilus
Haemophilus paraphrophilus is a species of ''Haemophilus ''Haemophilus'' is a genus of Gram-negative, pleomorphic, coccobacilli bacteria belonging to the family Pasteurellaceae. While ''Haemophilus'' bacteria are typically small coccobacilli, they are categorized as pleomorphic bacteria because of ...''. References paraphrophilus {{gammaproteobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggregatibacter Actinomycetemcomitans
''Aggregatibacter actinomycetemcomitans'' is a Gram-negative, facultative anaerobe, nonmotile bacterium that is often found in association with localized aggressive periodontitis, a severe infection of the periodontium. It is also suspected to be involved in chronic periodontitis. Less frequently, ''A. actinomycetemcomitans'' is associated with nonoral infections such as endocarditis. Its role in aggressive periodontitis was first discovered by Danish-born periodontist Jørgen Slots, a professor of dentistry and microbiology at the University of Southern California School of Dentistry. 'Bacterium actinomycetem comitans' was first described by Klinger (1912) as coccobacillary bacteria isolated with ''Actinomyces'' from actinomycotic lesions in humans. It was reclassified as ''Actinobacillus actinomycetemcomitans'' by Topley & Wilson (1929) and as ''Haemophilus actinomycetemcomitans'' by Potts ''et al.'' (1985). The species has attracted attention because of its association w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemophilus Parahaemolyticus
''Haemophilus'' is a genus of Gram-negative, pleomorphic, coccobacilli bacteria belonging to the family Pasteurellaceae. While ''Haemophilus'' bacteria are typically small coccobacilli, they are categorized as pleomorphic bacteria because of the wide range of shapes they occasionally assume. These organisms inhabit the mucous membranes of the upper respiratory tract, mouth, vagina, and intestinal tract. The genus includes commensal organisms along with some significant pathogenic species such as '' H. influenzae''—a cause of sepsis and bacterial meningitis in young children—and '' H. ducreyi'', the causative agent of chancroid. All members are either aerobic or facultatively anaerobic. This genus has been found to be part of the salivary microbiome. Metabolism Members of the genus ''Haemophilus'' will not grow on blood agar plates, as all species require at least one of these blood factors for growth: hemin (X-factor) and/or nicotinamide adenine dinucleotide ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hib Vaccine
The ''Haemophilus influenzae'' type B vaccine, also known as Hib vaccine, is a vaccine used to prevent ''Haemophilus influenzae'' type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis. It is recommended by both the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). Two or three doses should be given before six months of age. In the United States a fourth dose is recommended between 12 and 15 months of age. The first dose is recommended around six weeks of age with at least four weeks between doses. If only two doses are used, another dose later in life is recommended. It is given by injection into a muscle. Severe side effects are extremely rare. About 20 to 25% of people develop pain at the site of injection while about 2% develop a fever. There is no cle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemophilus Influenzae
''Haemophilus influenzae'' (formerly called Pfeiffer's bacillus or ''Bacillus influenzae'') is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37℃. ''H. influenzae'' was first described in 1892 by Richard Pfeiffer during an influenza pandemic when he incorrectly described ''Haemophilus influenzae'' as the causative microbe, which is why the bacteria retain the name "influenza". ''H. influenzae'' is responsible for a wide range of localized and invasive infections, typically in infants and children, including pneumonia, meningitis, or bloodstream infections. Treatment consists of antibiotics, however ''H. influenzae'' is often resistant to the penicillin family but augmentin can be used in mild cases. The recommended form of prevention is a series of the Hib vaccine and boosters, which are most often given under the ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
