Sporothrix schenckii: Difference between revisions

Revision as of 00:27, 21 November 2019

Dimorphic fungus that causes rose-handler's disease

Background

Microbiology

Dimorphic fungus with a hyaline, hyphated mold phase at 25ºC, and a round-to-oval budding yeast phase at body temperature
Produces melanin, a virulence factor

Epidemiology

Found in soil, decomposing plant matter, and peat moss worldwide
Acquired by traumatic implantation or inoculation of a preexisting wound

Clinical Presentation

Lymphocutaneous

Common cause of nodular lymphangitis
Incubation period 7 to 30 days
Nodules can be 2 to 4 cm, and appear along the lymphatics, typically in the arms and legs (and face, in children)
- They become indurated, then ulcerated
May have regional lymphadenopathy
Usually mild or no systemic symptoms

Fixed cutaneous

Only a single lesion, fixed at the point of inoculation
Lesions may be papular, plaques, nodular, verrucoud, or ulcerated

Disseminated or multifocal

Only occurs in patients with immunodeficiency, including alcoholism, diabetes, sarcoidosis, tuberculosis, transplantation, malignancy, immunosuppressive medication, or advanced HIV
Lesions can include ulcerations, aceniform, plaques, or crusts
Worst prognosis is with dissemination to lungs or meninges

Extracutaneous

Rare presentation without skin lesions, caused either by inhalation or deep inoculation
Musculoskeletal infections are the most common, with septic arthritis followed by osteomyelitis or tenosynovitis
Pulmonary sporotrichosis is more common in men aged 30 to 60 years, and presents similarly to pulmonary tuberculosis
Sporotrichotic meningitis is rare and occurs in immunocompromised patients
Can also affect eyes, genitals, or oropharyngeal mucosa

Diagnosis

Direct microscopy
- May see yeast forms or characteristic asteroid bodies (especially from deep swabs
Culture
- Sab + chloramphenicol at 25ºC for 5 to 7 days for mold form followed by BHI at 35-37ºC for 5 to 7 days for yeast form
Molecular tests
- Some labs have developed PCR diagnostics
Serology
- Tube or latex agglutination have specificity (95%) and sensitivity (98-100%)
- Immunoassays also exist
Sporotrichin skin test
- Essentially like a TB skin test but for sporotrichosis
- Only useful for epidemiologic surveys

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 == Background ==
+=== Microbiology ===
+* Dimorphic fungus with a hyaline, hyphated mold phase at 25ºC, and a round-to-oval budding yeast phase at body temperature
+* Produces melanin, a virulence factor
 === Epidemiology ===
-* Found in soil, decomposing plant matter, and peat moss
+* Found in soil, decomposing plant matter, and peat moss worldwide
-* Acquired by inoculation of a preexisting wound or penetration of intact skin
+* Acquired by traumatic implantation or inoculation of a preexisting wound
+== Clinical Presentation ==
+=== Lymphocutaneous ===
+* Common cause of [[nodular lymphangitis]]
+* Incubation period 7 to 30 days
+* Nodules can be 2 to 4 cm, and appear along the lymphatics, typically in the arms and legs (and face, in children)
+** They become indurated, then ulcerated
+* May have regional lymphadenopathy
+* Usually mild or no systemic symptoms
+=== Fixed cutaneous ===
+* Only a single lesion, fixed at the point of inoculation
+* Lesions may be papular, plaques, nodular, verrucoud, or ulcerated
+=== Disseminated or multifocal ===
+* Only occurs in patients with immunodeficiency, including alcoholism, diabetes, sarcoidosis, tuberculosis, transplantation, malignancy, immunosuppressive medication, or advanced HIV
+* Lesions can include ulcerations, aceniform, plaques, or crusts
+* Worst prognosis is with dissemination to lungs or meninges
+=== Extracutaneous ===
+* Rare presentation without skin lesions, caused either by inhalation or deep inoculation
+* Musculoskeletal infections are the most common, with septic arthritis followed by osteomyelitis or tenosynovitis
+* Pulmonary sporotrichosis is more common in men aged 30 to 60 years, and presents similarly to [[pulmonary tuberculosis]]
+* Sporotrichotic meningitis is rare and occurs in immunocompromised patients
+* Can also affect eyes, genitals, or oropharyngeal mucosa
+== Diagnosis ==
+* Direct microscopy
+** May see yeast forms or characteristic asteroid bodies (especially from deep swabs
+* Culture
+** Sab + chloramphenicol at 25ºC for 5 to 7 days for mold form followed by BHI at 35-37ºC for 5 to 7 days for yeast form
+* Molecular tests
+** Some labs have developed PCR diagnostics
+* Serology
+** Tube or latex agglutination have specificity (95%) and sensitivity (98-100%)
+** Immunoassays also exist
+* Sporotrichin skin test
+** Essentially like a TB skin test but for sporotrichosis
+** Only useful for epidemiologic surveys
+== Further Reading ==
+* [https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/sporothrix-schenckii.html Pathogen Safety Data Sheets: Infectious Substances – Sporothrix schenckii].
 {{DISPLAYTITLE:''Sporothrix schenckii''}}