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previously Actinomyces naeslundii genospecies 2 Taxonomy Family: Actinomycetaceae, Natural habitats They are commonly isolated in the human oral cavity and play a major role in the formation of oral biofilm or dental plaque. Clinical significance A. oris, A. odontolyticus, and A. viscosus are the primary Actinomyces species in infants' mouths as well as in early dental plaque. A. oris it has also been linked to root caries, periodontal disease and even opportunistic infections such as actinomycosis.
Taxonomy Family: Bifidobacteriaceae Natural habitats They can be found in the anorectal biota of healthy adults of both sexes as well as in that for children. It is also part of the endogenous vaginal biota of in women of reproductive age. The optimal pH for the growth of G. vaginalis is between 6 and 7, at elevated pH in the vagina. The organism can also be recovered from the urethras of the male partners of women with bacterial vaginosis. Clinical significance The "gold standard" for the diagnosis of BV (bacterial vaginosis) is direct examination of vaginal secretions and not the culture of G. vaginalis, since G. vaginalis can also be recovered from healthy women. BV is examination of the vaginal discharge to detect thr typical "fishy" trimethylamine odor, wich is enhanced after alkalinization with 10% KOH. The typical smear of vaginal discharge from BV patients shows "Clue cells" (bacteria covering epithelial cell margins) together with a mixed biota consisting of large numbers of gram-negative (predominantly Prevotella and Porphyromonas spp) and gram-variable (G. vaginalis) rods and coccobacilly, wheras lactobacilli are almost always absent. The isolation of G. vaginalis can support the diagnosis of BV.
Tsukamurella species are frequently misidentified as Rhodococcus or Corynebacterium species. Taxonomy Family: Tsukamurellaceae Natural habitats They have been found in soil, sludge, and arthropods. Clinical significance Are rarely found in humans. Can cause opportunistic infections in humans. Known infections are from the skin, peritonitis and catheter-related sepsis.
The Streptomyces group contains approximately 597 validly named species or subspecies and remains problematic. Many of these species have been patented because of the commercially useful products they synthesize. Taxonomy Family: Streptomycetaceae Natural habitats In the environment, soil, sand and rotten plant material. Especially from North- and South America, Africa and Arabia. Clinical significance The most common type of infection is mycetoma, they penetrate in wounds in the skin.
Formerly known as Oerskovia xanthineolytica Taxonomy Family: Promicromonosporaceae Former name: Oerskovia xanthineolytica Natural habitats The environment like the soil, water, decaying plant material. Clinical significance Rarely cause human infections. Infections mainly occur in immunocompromised patients and very often associated with a foreign body.
Taxonomy Family: Nocardiaceae Natural habitats While the aerobic Actinomycetes are widely distributed in the environment, the extent to which particular species geographically restricted is not well known. Their primary ecological niche is probably the decomposition of plants material. Clinical significance Nocardia infections generally result either from trauma related introduction of the organism or, particularly in immunocompromised patients, from inhalation and the resulting formation of a pulmonary focus. The most common form of human nocardiosis disease is a slowly progressive pneumonia, the common symptoms of which include cough, dyspnea, and fever. It is not uncommon for this infection to spread to the pleura or chest wall. Every organ can be affected if a systemic spread takes place. They are involved in the process of endocarditis and the infection can take the form of encephalitis and/or brain abscesses.
Taxonomy Family: Nocardiaceae Natural habitats While the aerobic Actinomycetes are widely distributed in the environment, the extent to which particular species geographically restricted is not well known. Their primary ecological niche is probably the decomposition of plants material. Clinical significance They produces an actinomycotic mycetoma in humans. The pus can have sulfur granule or grain, a clumping of filamentous bacteria seen in infected living tissue, this is considered characteristic of the infection, but is not always present and is also not specific.
Isolates of this species are perhaps the most resistant of all Nocardia isolates Taxonomy Family: Nocardiaceae Natural habitats While the aerobic Actinomycetes are widely distributed in the environment, the extent to which particular species geographically restricted is not well known. Their primary ecological niche is probably the decomposition of plants material. Clinical significance Nocardia infections generally result either from trauma related introduction of the organism or, particularly in immunocompromised patients, from inhalation and the resulting formation of a pulmonary focus. The most common form of human nocardiosis disease is a slowly progressive pneumonia, the common symptoms of which include cough, dyspnea, and fever. It is not uncommon for this infection to spread to the pleura or chest wall. Every organ can be affected if a systemic spread takes place. They are involved in the process of endocarditis and the infection can take the form of encephalitis and/or brain abscesses.
Taxonomy Family:Micrococcaceae Natural habitats Is a normal in habitant of the mouth and upper respiratory tract. Clinical significance Isolated from dental carries and very rarely cause disease. The most common infection is endocarditis, in people with underlying heart valve disorder.
Actinomyces graevenitzii is a newly recognized Actinomyces species that is seldom isolated from clinical specimens. This organism is an opportunistic human pathogen. Taxonomy Family: Actinomycetaceae Natural habitats It is possible a component of the oral pharyngeal flora. Very little is known about the clinical features and pathogenesis Clinical significance A. graevenitzii is believed to be associated with classic actinomycosis. Isolated from human clinical specimens, mainly respiratory tract secretions.
