Actinomyces: Difference between revisions

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Background

Microbiology

Genus of weakly Gram-positive branching bacillus that looks fungal under microscopy
Molar tooth appearance of colonies
Member of oral and gut flora
Often part of polymicrobial infections involving other commensal flora
Includes the following species of medical importance: Actinomyces israelii (most commone), Actinomyces gerencseriae, Actinomyces meyeri (more likely to disseminate), Actinomyces viscosus, Actinomyces naeslundii, Actinomyces odontolyticus, Actinomyces neuii, Actinomyces turicensis, Actinomyces radingae, Actinomyces pyogenes, Actinomyces georgiae, Actinomyces graevenitzii, Actinomyces propionica

Pathophysiology

Spreads by direct invasion through tissue and creating fistulae

Clinical Manifestations

Cervicofacial Actinomycosis

"Lumpy jaw syndrome" with painless jaw mass, trismus, and eventually pain
- Starts as mass or cold abscess in neck, jaw, or mouth
- Can invade bone
- Spreads contiguously
Often no systemic symptoms like fever
May have "sulfur granules" discharge
Most common form, accounting for ~50% of cases

Abdominal Actinomycosis

Presents as an abdominal mass that fistulizes to skin
- Organs affected can include appendix, cecum, colon, liver, biliary tract, pancreas, esophagus, rectum, and spleen
Second most common presentation in about 25% of cases

Thoracic Actinomycosis

Includes pulmonary, bronchial, and laryngeal actinomycosis
Presents as a chronic, non-resolving pneumonia or as a lung cancer
Can spread directly to involve heart as well
Accounts for about 15% of cases

Pelvic Actinomycosis

Less than 5% of cases
Can involve uterus, fallopian tubes, ovaries, bladder, and kidneys

Others

Soft tissue infections
Bone and joint infections
CNS infections
Endocarditis
Blood culture contamination1

Diagnosis

Isolation of Actinomyces in culture from a sterile site
Identification of sulfur granules with compatible clinical syndrome and/or histology

Management

First-line is penicillin IV x4-6 weeks then penicillin PO x6-12 months
Alternatives include ceftriaxone, clindamycin, and doxycycline
May need surgery, including for abscess drainage, debridement, management of fistulas, etc.

References

^ Anna Jeffery-Smith, Caoimhe Nic-Fhogartaigh, Michael Millar. P. Bourbeau. Is the Presence of Actinomyces spp. in Blood Culture Always Significant?. Journal of Clinical Microbiology. 2016;54(4):1137-1139. doi:10.1128/jcm.03074-15.

@@ Line 1: / Line 1: @@
+==Background==
-= Microbiology =
+===Microbiology===
-* Weakly Gram-positive bacterium that looks fungal under microscopy
-* Oral and gut flora
-* Spreads by direct invasion through tissue and creating fistulae
+*Genus of weakly [[Stain::Gram-positive]] branching [[Shape::bacillus]] that looks fungal under microscopy
-= Syndromes =
+*Molar tooth appearance of colonies
+*Member of oral and gut flora
+*Often part of polymicrobial infections involving other commensal flora
+*Includes the following species of medical importance: [[Actinomyces israelii]] (most commone), [[Actinomyces gerencseriae]], [[Actinomyces meyeri]] (more likely to disseminate), [[Actinomyces viscosus]], [[Actinomyces naeslundii]], [[Actinomyces odontolyticus]], [[Actinomyces neuii]], [[Actinomyces turicensis]], [[Actinomyces radingae]], [[Actinomyces pyogenes]], [[Actinomyces georgiae]], [[Actinomyces graevenitzii]], [[Actinomyces propionica]]
+=== Pathophysiology ===
-== Cervicofacial actinomycosis ==
+*Spreads by direct invasion through tissue and creating fistulae
+==Clinical Manifestations==
-* &quot;Lumpy jaw syndrome&quot; with painless jaw mass, trismus, and eventually pain
-* Most common form, accounting for ~50% of cases
+===Cervicofacial Actinomycosis===
-== Abdominal actinomycosis ==
+*"Lumpy jaw syndrome" with painless jaw mass, trismus, and eventually pain
-* Presents as an abdominal mass that fistulizes to skin
+**Starts as mass or cold abscess in neck, jaw, or mouth
+**Can invade bone
+**Spreads contiguously
+*Often no systemic symptoms like fever
+*May have "sulfur granules" discharge
+*Most common form, accounting for ~50% of cases
+===Abdominal Actinomycosis===
-== Pulmonary actinomycosis ==
-* Presents as a chronic, non-resolving pneumonia or as a lung cancer
+*Presents as an abdominal mass that fistulizes to skin
+**Organs affected can include appendix, cecum, colon, liver, biliary tract, pancreas, esophagus, rectum, and spleen
-* Can spread directly to involve heart as well
+*Second most common presentation in about 25% of cases
+===Thoracic Actinomycosis===
-== Others ==
+*Includes pulmonary, bronchial, and laryngeal actinomycosis
-* Endocarditis
+*Presents as a chronic, non-resolving [[pneumonia]] or as a lung cancer
+*Can spread directly to involve heart as well
+*Accounts for about 15% of cases
+=== Pelvic Actinomycosis ===
-= Management =
+* Less than 5% of cases
-* IV penicillin x4-6 weeks then PO penicillin x6-12 months
+* Can involve uterus, fallopian tubes, ovaries, bladder, and kidneys
-* Alternatives include ceftriaxone, amox/clav
+===Others===
-{{DISPLAYTITLE:''Actinomyces'' species}}
+*Soft tissue infections
+*Bone and joint infections
+*CNS infections
+*[[Endocarditis]]
+*[[Blood culture contamination]][[CiteRef::bourbeau2016is]]
+== Diagnosis ==
+* Isolation of ''Actinomyces'' in culture from a sterile site
+* Identification of sulfur granules with compatible clinical syndrome and/or histology
+==Management==
+*First-line is [[Is treated by::penicillin]] IV x4-6 weeks then [[penicillin]] PO x6-12 months
+*Alternatives include [[Is treated by::ceftriaxone]], [[Is treated by::clindamycin]], and [[Is treated by::doxycycline]]
+*May need surgery, including for abscess drainage, debridement, management of fistulas, etc.
+== Further Reading ==
+* ''Actinomyces'' and Related Organisms in Human Infections. doi: [https://journals.asm.org/doi/10.1128/CMR.00100-14 https://doi.org/10.1128/CMR.00100-14]
+{{DISPLAYTITLE:''Actinomyces''}}
 [[Category:Bacteria]]