www.medigraphic.org.mx New observations on the ecology and epidemiology of Sporothrix schenckii and sporotrichosis 2. Ecological niches of S. schenckii and zoonotic outbreaks Key words: Sporothrix schenckii, Teodoro Carrada-Bravo,* sporotrichosis, ecology, epidemiology, Miguel Iván Olvera-Macías* zoonotic disease, HIV infection. * Sporotrichosis Research Unit, Tropical Medicine Research Centre. Palabras clave: Sporothrix schenckii, esporotricosis, ecología, epidemiología, Correspondencia: enfermedad zoonótica, infección por VIH. Teodoro Carrada-Bravo, M.D. Calzada de los Rincones 694, Recibido: 23/09/2012 Col. Las Plazas, 36620, Aceptado: 16/11/2012 Irapuato, Guanajuato, México. E-mail: [email protected] Este artículo puede ser consultado 5 en versión completa en: Color images available at: www.medigraphic.com/patologiaclinica www.medigraphic.com/patologiaclinica Imágenes a color disponibles en: www.medigraphic.com/patologiaclinica Abstract Resumen Sporotrichosis is the most common subcutaneous mycosis La esporotricosis es la micosis subcutánea más prevalente in the Americas, Japan, India and South Africa. Classically, en las Américas, Japón, India y Sudáfrica. Clásicamente, infection was associated with out-of-door occupations and la infección se asociaba con la inoculación traumática del the traumatic inoculation of soil, vegetables, thorns, straws suelo, vegetales, espinas, paja o zacates contaminados con and grasses, contaminated with S. schenckii. This paper pre- S. schenckii. Esta publicación presenta la ecología del micro- sents the fungus ecology and disease risk-factors, according organismo y los factores de riesgo de la enfermedad, según to recent epidemiologic and laboratory research work. From los trabajos de investigación más recientes, referentes a la 2005 through 2008, 804 human new cases were diagnosed at epidemiología y laboratorio. Del 2005 al 2008, se diagnos- the Evandro Chagas Clinical Research Institute (IPEC), most ticaron 804 casos nuevos en el Instituto de Investigación affected were women 40-49 years, engaged in domestic duties Evandro Chagas (IPEC) en Río de Janeiro, Brasil. Las más and from deprived social strata. Close contact with cats was atacadas fueron las mujeres de 40-49 años de edad, amas recorded in 91% of human cases, biteswww.medigraphic.org.mx or scratches were de casa procedentes de los estratos sociales más pobres. reported by 68% of patients. Also 64 dogs and 1,503 infected El contacto directo con los gatos se reportó en 91% de los cats were confirmed at IPEC. Canine sporotrichosis presented casos humanos, el antecedente de mordeduras y arañazos as self limited mycosis. Feline disease varied from subclinical fue recabado en 68% de los afectados. Además, en el IPEC infection to systemic disease with hematogenous dissemination se confirmaron más de 1,503 gatos y 64 perros infectados. of S. schenckii. The cat’s zoonotic potential was demonstrated La esporotricosis canina se comportó como enfermedad by isolation of S. schenckii from skin lesions biopsy, and the ma- autolimitada. La enfermedad gatuna varió desde una infec- Rev Latinoamer Patol Clin, Vol. 60, Núm. 1, pp 5-24 • Enero - Marzo, 2013 Carrada-Bravo T et al. Ecological niches of S. schenckii and zoonotic outbreaks terials collected from oral-nasal cavities, and nails. From 1999 ción subclínica, hasta la forma sistémica con diseminación through 2009, there were 21 HIV patients with sporotrichosis hematógena de S. schenckii. El potencial zoonótico de los the largest case series reported to date. Eleven (52.4%) were felinos se demostró por el aislamiento de S. schenckii a partir treated with oral itraconazole and eight (38.1%) amphotericin- de las biopsias de piel y de las cavidades oronasal y de las B, with an overall excellent cure rate of 81%. uñas. De 1999 a 2009, hubo 21 enfermos VIH-positivos con esporotricosis, la serie más grande reportada hasta esta fecha. Once (52.4%) fueron tratados con itraconazol oral y ocho (38.1%) recibieron amfotericina B, con una tasa de curación excelente de 81%. Defi nition The new taxonomy and mycology porotrichosis is a chronic infection usually Sporothrix schenckii an eukaryotic organism, has Slimited to cutaneous and subcutaneous tis- chitin on its cell wall.3 For several year it was sues; it involves all layers of skin and the sub- classified as Deuteromycotina, however, recent cutaneous lymphatics.1 The disease is caused research imply it is an ascomycete (Ascomycota, by different species of the dimorphic fungus class Pyrenomycetes, order Ophiotomatales, family Sporothrix schenckii.2,3 The fungus is present in Ophiostomataceae), since it has simple septum with the environment in soil, plants and animals, it in- Woronin bodies, and three chitin synthasa genes,9 vades through skin injury. Many times, injury is so the fungus produces dematiaceous (melanin +) minor that it goes unrecognized and neglected.4 conidia,10 and does not produce perithecium on 6 The fungus produces indolent lesion which ap- malt, rice or potato media. The sexual form of S. pears as small erythematous nodule or verrucous schenckii is as yet unknown.3 plaque, and may remain localized (fixed type), or S. schenckii is one of several fungal pathogens spread centrally through the lymphatic draining that exhibit temperature dimorphism,1,7 In the the area, establishing a chain of granulomatous, environment or the laboratory, on standard cul- ulcerating nodules (lymphocutaneous type). Spo- ture media such as Mycosel-cycloheximide or rotrichosis generally affects the exposed parts Saboureaud-dextrose-agar at 25 oC, after four days of the body, namely, the hands, arms, face and it forms moist, white to cream colored colonies, legs.5,6 Pulmonary sporotrichosis results from shiny at first and later become fuzzy. In time, the inhalation of the fungal spores, and occurs in colony is membranous, brown to black and myce- humans with a variety of underlying conditions lial (M) (figure 1). Some primary isolates have the such as sarcoidosis, malignant neoplasm, diabetes ability to form dark colonies from the beginning of mellitus, and chronic alcoholism.5 Infection may growth (figure 2). disseminate to become generalized involving At room temperature the fungus has thin sep- skin, bones, joints, bursa and the central nervous tate and branching hyphae 1 to 2 mμ in diameter. system. Patients with acquired immunodeficiency Microscopic observation of M-saprophytic stage syndrome (AIDS), or immunosuppressant,www.medigraphic.org.mx are at shows thin walled hyaline conidia, however, the greater risk of multifocal, hematogenous spread presence or dark brown thick walled solitary co- and disseminated fatal infection.6 nidia, tear or globose shaped, arranged in sleeves Extracutaneous sporotrichosis shows marked around the main hyphal axis, and the oval borne male predominance 6:1 in widely scattered areas, sympodially on a lateral conidiophores (figure 3), most affected were males 24-50 years of age.7,8 their shape suggest a palm tree or flower head1,2 Rev Latinoamer Patol Clin, Vol. 60, Núm. 1, pp 5-24 • Enero - Marzo, 2013 Carrada-Bravo T et al. Ecological niches of S. schenckii and zoonotic outbreaks A B C Figure 1. Colonial Morphol- ogy. A: Two white colonies, initial isolate from a case of articular disease. B: Colo- nial side view of a «volcano on an island». C: After two weeks, folded, black-brown with radial grooves (Cour- tesy Dr. J. W. Rippon). A B by radiated eosinophilic substance, with covering of approximately 10 mμ in thickness called asteroid bodies1,6 (figure 5). The dimorphic M-Y transformation involves calcium/calmodulin-dependent protein-kinases and, signaling interaction between cytosolic phos- pholipase and protein G.12,13 Y-cells grow well within pH range 3.0-8.5, and NaCl 11%.11 When 25 °C 37 °C yeasts are cultured in albumin-containing medium, Figure 2. A: Primary isolates from cavitary pulmonary dis- two extracellular proteinases are produced: 1) ease, black and wrinkled folded colonies (25 oC). B: Trans- chymotrypsin-like, molecular weight (mw) of 36, ferred to BHI-agar al 37 oC, glistening, white, soft Yeast- colonies (Courtesy Dr. J. W. Rippon). 500, optimal pH 6.0, and 2) cathepsin-D-like, mw 39 000, optimal pH 3.5 these two enzymes may 7 (figure 4). M-stage grows well on pH around 3.0 to be related to the virulence of the fungus since they 11.5 and can withstand Na Cl 7%.10,11 hydrolyse substrates such as stratum corneum, col- The yeast (Y) stage can be produced in vitro lagen I, and elastin.14 All strains are able to split urea, by culturing mycelia or conidia in rich medium and can tolerate cycloheximide at 0.25%, thiamine such as brain-heart-infusion agar (BHI) at 37 oC. is required for good fungal growth.1-3 The Y-colony is pasty, glabrous, dull white, or tan, Laboratory animals such as mice, rats, guinea soft and bacteria-like with a wrinkled surface. The pigs and hamsters are susceptible to sporotricho- yeast cells generated in vitro are oval, sub globose sis.7 When a conidial suspension is injected intra- or cigar-shaped with one or several buds. In the peritoneally into male mice, orchitis is recorded hamster and human tissues, Y-cells are surrounded within 10 days to two weeks. Testes with lower Flowerette arrengement www.medigraphic.org.mxwww.medigraphi Figure 3. Mycelial microscopic morphology. A: Globose dark conidia, on side of a hypha x 1,080. B: Elliptical to oblong hyaline and pig- Solitary mented, dense conidia along the hypha axis x conidia 1,417. C: Triangular deeply pigmented macro conidia. They appear to be more resistant to AB Cdrying and UV-light, and are also more virulent for mice x 2,060 (Courtesy of Dr. F. Mariat). Rev Latinoamer Patol Clin, Vol. 60, Núm. 1, pp 5-24 • Enero - Marzo, 2013 Carrada-Bravo T et al. Ecological niches of S. schenckii and zoonotic outbreaks and tail may be observed. Congenitally athymic CONIDIA (nu/nu) mice are found to be far more susceptible to iv-challenge than their phenotypic ally normal littermates, suggesting T-lymphocytes are critical to host resistance.7 Molecular techniques have been used to DENTICLE asses genetic variability of the complex-species S.