Actinomyces israelii: Difference between revisions
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==Overview== | ==Overview== | ||
'''''Actinomyces israelii''''' is a species of [[Gram-positive]], rod-shaped [[bacteria]] within the ''[[Actinomyces]]''. Known to live commensally on and within humans, ''A. israelii'' is an opportunistic pathogen and a cause of [[actinomycosis]]. Many physiologically diverse strains of the species are known to exist, though all are strict [[anaerobe]]s.<ref>Levinson, W. ''Review of Medical Microbiology and Immunology''. 2010:McGraw Hill.</ref> | '''''Actinomyces israelii''''' is a species of [[Gram-positive]], rod-shaped [[bacteria]] within the ''[[Actinomyces]]''. Known to live [[Commensal|commensally]] on and within humans, ''A. israelii'' is an [[opportunistic pathogen]] and a cause of [[actinomycosis]]. Many physiologically diverse strains of the species are known to exist, though all are strict [[anaerobe]]s.<ref>Levinson, W. ''Review of Medical Microbiology and Immunology''. 2010:McGraw Hill.</ref> | ||
==Pathogenesis== | ==Pathogenesis== | ||
[[Actinomycosis]] is most frequently caused by ''A. israelii''. It is a normal colonizer of the vagina,<ref name="Hoffman2012">{{cite book | last = Hoffman | first = Barbara | title = Williams gynecology, 2nd edition | publisher = McGraw-Hill Medical |page=65 |location = New York | year = 2012 | isbn = 0071716726 }}</ref> colon, and mouth. Infection is established first by a breach of the mucosal barrier during various procedures (dental, gastrointestinal), aspiration, or pathologies such as [[diverticulitis]]. The chronic phase of this disease is also known the "classic phase" because the acute, early phase is often missed by health care providers. This is characterized by slow, contiguous growth that ignores tissue planes and forms a sinus tract that can spontaneously heal and recur, leading to a densely fibrotic lesion. This lesion is often characterized as "wooden". Sulfur granules form in a central purulence surrounded by neutrophils. This conglomeration of organisms is virtually diagnostic of ''A. israelii.'' | [[Actinomycosis]] is most frequently caused by ''A. israelii''. It is a normal colonizer of the vagina,<ref name="Hoffman2012">{{cite book | last = Hoffman | first = Barbara | title = Williams gynecology, 2nd edition | publisher = McGraw-Hill Medical |page=65 |location = New York | year = 2012 | isbn = 0071716726 }}</ref> colon, and mouth. Infection is established first by a breach of the mucosal barrier during various procedures (dental, gastrointestinal), aspiration, or pathologies such as [[diverticulitis]]. The chronic phase of this disease is also known the "classic phase" because the acute, early phase is often missed by health care providers. This is characterized by slow, contiguous growth that ignores tissue planes and forms a sinus tract that can spontaneously heal and recur, leading to a densely fibrotic lesion. This lesion is often characterized as "wooden". Sulfur granules form in a central purulence surrounded by [[Neutrophil|neutrophils]]. This conglomeration of organisms is virtually diagnostic of ''A. israelii.'' | ||
<!-- not specific to this species Oral-cervicofacial disease is the most common form of actinomycosis. It is characterized by a painless "lumpy jaw". Lymphadenopathy is uncommon in this form of the disease. Another form of actinomycosis is thoracic disease, which is often misdiagnosed as a neoplasm, as it forms a mass that extends to the chest wall. It arises from aspiration of organisms from the oropharynx. Symptoms include chest pain, fever, and weight loss. Abdominal disease is another manifestation of actinomycosis. This can lead to a sinus tract that drains to the abdominal wall or the perianal area. Symptoms include fever, abdominal pain, and weight loss.<ref name="El Sahli_2007">El Sahli, MD, MS. "Anaerobic Pathogens." ''Infectious Disease Module 2007.'' Baylor College of Medicine, 2007.</ref> ''Actinomyces'' species have also been shown to infect the central nervous system in a dog "without history or evidence of previous trauma or other organ involvement." <ref>{{cite journal|last=Couto|first=SS|author2=Dickinson, PJ|author3=Jang, S|author4=Munson, L|title=Pyogranulomatous meningoencephalitis due to Actinomyces sp. in a dog.|journal=Veterinary pathology|date=November 2000|volume=37|issue=6|pages=650–2|pmid=11105955|doi=10.1354/vp.37-6-650}}</ref> | <!-- not specific to this species Oral-cervicofacial disease is the most common form of actinomycosis. It is characterized by a painless "lumpy jaw". Lymphadenopathy is uncommon in this form of the disease. Another form of actinomycosis is thoracic disease, which is often misdiagnosed as a neoplasm, as it forms a mass that extends to the chest wall. It arises from aspiration of organisms from the oropharynx. Symptoms include chest pain, fever, and weight loss. Abdominal disease is another manifestation of actinomycosis. This can lead to a sinus tract that drains to the abdominal wall or the perianal area. Symptoms include fever, abdominal pain, and weight loss.<ref name="El Sahli_2007">El Sahli, MD, MS. "Anaerobic Pathogens." ''Infectious Disease Module 2007.'' Baylor College of Medicine, 2007.</ref> ''Actinomyces'' species have also been shown to infect the central nervous system in a dog "without history or evidence of previous trauma or other organ involvement." <ref>{{cite journal|last=Couto|first=SS|author2=Dickinson, PJ|author3=Jang, S|author4=Munson, L|title=Pyogranulomatous meningoencephalitis due to Actinomyces sp. in a dog.|journal=Veterinary pathology|date=November 2000|volume=37|issue=6|pages=650–2|pmid=11105955|doi=10.1354/vp.37-6-650}}</ref> | ||
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== References == | == References == | ||
{{Reflist|2}} | {{Reflist|2}} | ||
Latest revision as of 13:28, 7 April 2017
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 Scanning electron micrograph of Actinomyces israelii.
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| Actinomyces israelii (Kruse 1896) Lachner-Sandoval 1898 |
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Actinomycosis Microchapters |
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Diagnosis |
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Actinomyces israelii On the Web |
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American Roentgen Ray Society Images of Actinomyces israelii |
This page is about microbiologic aspects of the organism(s). For clinical aspects of the disease, see Actinomycosis.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Actinomyces israelii is a species of Gram-positive, rod-shaped bacteria within the Actinomyces. Known to live commensally on and within humans, A. israelii is an opportunistic pathogen and a cause of actinomycosis. Many physiologically diverse strains of the species are known to exist, though all are strict anaerobes.[1]
Pathogenesis
Actinomycosis is most frequently caused by A. israelii. It is a normal colonizer of the vagina,[2] colon, and mouth. Infection is established first by a breach of the mucosal barrier during various procedures (dental, gastrointestinal), aspiration, or pathologies such as diverticulitis. The chronic phase of this disease is also known the "classic phase" because the acute, early phase is often missed by health care providers. This is characterized by slow, contiguous growth that ignores tissue planes and forms a sinus tract that can spontaneously heal and recur, leading to a densely fibrotic lesion. This lesion is often characterized as "wooden". Sulfur granules form in a central purulence surrounded by neutrophils. This conglomeration of organisms is virtually diagnostic of A. israelii.
References
- ↑ Levinson, W. Review of Medical Microbiology and Immunology. 2010:McGraw Hill.
- ↑ Hoffman, Barbara (2012). Williams gynecology, 2nd edition. New York: McGraw-Hill Medical. p. 65. ISBN 0071716726.