Sporotrichosis laboratory findings: Difference between revisions
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* The etiological agent may be obtained when the specimen is cultured on Sabouraud agar with chloramphenicol or on mycobiotic agar.<ref name="pmid21653757">{{cite journal| author=Oliveira DC, Lopes PG, Spader TB, Mahl CD, Tronco-Alves GR, Lara VM et al.| title=Antifungal susceptibilities of Sporothrix albicans, S. brasiliensis, and S. luriei of the S. schenckii complex identified in Brazil. | journal=J Clin Microbiol | year= 2011 | volume= 49 | issue= 8 | pages= 3047-9 | pmid=21653757 | doi=10.1128/JCM.00255-11 | pmc=PMC3147739 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21653757 }} </ref> | * The etiological agent may be obtained when the specimen is cultured on Sabouraud agar with chloramphenicol or on mycobiotic agar.<ref name="pmid21653757">{{cite journal| author=Oliveira DC, Lopes PG, Spader TB, Mahl CD, Tronco-Alves GR, Lara VM et al.| title=Antifungal susceptibilities of Sporothrix albicans, S. brasiliensis, and S. luriei of the S. schenckii complex identified in Brazil. | journal=J Clin Microbiol | year= 2011 | volume= 49 | issue= 8 | pages= 3047-9 | pmid=21653757 | doi=10.1128/JCM.00255-11 | pmc=PMC3147739 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21653757 }} </ref> | ||
* Filamentous hyaline colonies begin to grow following 5-7 days of incubation at 25ºC, and may manifest with pigmented centers.<ref name="pmid12372075">{{cite journal| author=Morris-Jones R| title=Sporotrichosis. | journal=Clin Exp Dermatol | year= 2002 | volume= 27 | issue= 6 | pages= 427-31 | pmid=12372075 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12372075 }} </ref> | * Filamentous hyaline colonies begin to grow following 5-7 days of incubation at 25ºC, and may manifest with pigmented centers.<ref name="pmid12372075">{{cite journal| author=Morris-Jones R| title=Sporotrichosis. | journal=Clin Exp Dermatol | year= 2002 | volume= 27 | issue= 6 | pages= 427-31 | pmid=12372075 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12372075 }} </ref> | ||
* | * Ultimately, the isolation of ''S. schenckii'' is dependent on 5-7 day a subculture of the fungus on enriched agars, such as Brain Heart Infusion agar, at 35-37ºC. Isolation is verified following the demonstration of dimorphism. | ||
* Sporotrichosis is a [[chronic (medicine)|chronic]] disease with slow progression and often subtle symptoms. It is difficult to diagnose, as many other diseases share similar symptoms and therefore must be ruled out. | * Sporotrichosis is a [[chronic (medicine)|chronic]] disease with slow progression and often subtle symptoms. It is difficult to diagnose, as many other diseases share similar symptoms and therefore must be ruled out. | ||
* While within human and animal tissues, ''S. schenckii'' exists in its yeast form. | * While within human and animal tissues, ''S. schenckii'' exists in its yeast form. | ||
Revision as of 15:13, 25 January 2016
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alison Leibowitz [2]
Laboratory findings
- Definitive diagnosis of Sporotrichosis occurs upon the isolation and identification of S. schenckii in culture.
- The etiological agent may be obtained when the specimen is cultured on Sabouraud agar with chloramphenicol or on mycobiotic agar.[1]
- Filamentous hyaline colonies begin to grow following 5-7 days of incubation at 25ºC, and may manifest with pigmented centers.[2]
- Ultimately, the isolation of S. schenckii is dependent on 5-7 day a subculture of the fungus on enriched agars, such as Brain Heart Infusion agar, at 35-37ºC. Isolation is verified following the demonstration of dimorphism.
- Sporotrichosis is a chronic disease with slow progression and often subtle symptoms. It is difficult to diagnose, as many other diseases share similar symptoms and therefore must be ruled out.
- While within human and animal tissues, S. schenckii exists in its yeast form.
- Varying in size and shape, these curved cells typically have 2-6 μm diameters with cigar-like buds offshooting from a narrow base.
- Growing on Sabouraud dextrose agar, most S. schenckii strains become evident after 4 days. At this point, some strains lack dark pigment, while others have been infiltrated with dark pigment from the start. Upon transfer to Brain-Heart Infusion (BHI) agar, and cultured for 7 days at 37°C, the S. schenckii strains undergo dimorphism, manifesting as creamy off-white to beige colored colonies.[3]
- Patients with sporotrichosis will likely have antibodies against the fungus S. schenckii, however, due to variability in sensitivity and specificity, antibody identification may not be a reliable diagnosis for this disease. The confirming diagnosis remains culturing the fungus from the skin, sputum, synovial fluid, and cerebrospinal fluid.
- Cats with sporotrichosis are unique in that the exudate from their lesions may contain numerous organisms. This makes cytological evaluation of exudate a valuable diagnostic tool in this species. Exudate is pyogranulomatous and phagocytic cells may be packed with yeast forms. These are variable in size, but many are cigar-shaped.[4]
Culture and Identification
The gold standard for diagnosis of Sporotrichosis is with fungal culture. The tree below serves as an identification key for six Sporothrix species of clinical interest:
References
- ↑ Oliveira DC, Lopes PG, Spader TB, Mahl CD, Tronco-Alves GR, Lara VM; et al. (2011). "Antifungal susceptibilities of Sporothrix albicans, S. brasiliensis, and S. luriei of the S. schenckii complex identified in Brazil". J Clin Microbiol. 49 (8): 3047–9. doi:10.1128/JCM.00255-11. PMC 3147739. PMID 21653757.
- ↑ Morris-Jones R (2002). "Sporotrichosis". Clin Exp Dermatol. 27 (6): 427–31. PMID 12372075.
- ↑ 3.0 3.1 Barros MB, de Almeida Paes R, Schubach AO (2011). "Sporothrix schenckii and Sporotrichosis". Clin Microbiol Rev. 24 (4): 633–54. doi:10.1128/CMR.00007-11. PMC 3194828. PMID 21976602.
- ↑ Alvarado-Ramírez E, Torres-Rodríguez JM (2007). "In vitro susceptibility of Sporothrix schenckii to six antifungal agents determined using three different methods". Antimicrob Agents Chemother. 51 (7): 2420–3. doi:10.1128/AAC.01176-06. PMC 1913275. PMID 17438048.