Müeller-Hinton methylene blue media as an alternative to RPMI 1640 for determining the susceptibility of Cryptococcus neoformans and Cryptococcus gattii to posaconazole with Etest.

Mueller-Hinton modified agar (MH-GMB) was compared with RPMI + 2% glucose-agar to determine the MICs of 80 isolates of Cryptococcus neoformans and C. gattii to posaconazole with Etest. MH-GMB minimised trailing and agreement between both media was 94%. Agreement of M27-A2 microbroth reference method was 98% with RPMI and 94% with MB-GMB.

Laccase activity in Cryptococcus gattii strains isolated from goats.

Cryptococcosis is a life-threatening infection in humans and animals caused by encapsulated yeasts of the genus Cryptococcus. Cryptococcus neoformans and Cryptococcus gattii are the main agents of this mycosis. Until 2002 C. gattii was classified as a variety of C. neoformans but now is accepted as an independent species. The laccase (phenoloxydase) enzyme produced by these yeasts is considered one of the main pathogenic factors for its ability to induce melanin from dihydroxyphenolic compounds. The vast majority of the studies in laccase and melanin synthesis have been developed using isolates of C. neoformans. The main objective of this study was to evaluate laccase activity in strains of C. gattii, serotype B isolated from immunocompetent goats that died of lung and disseminated cryptococcosis, in several outbreaks occurring in Spain. The laccase activities of these isolates were compared with those of other strains of C. gattii and C. neoformans. After fungal cell rupture, the supernatant of each isolate was analyzed for its laccase activity using as substrate an L-dopa 20 mM solution. The degree of enzymatic activity was assessed according to its absorbance at 450 nm and scored using Enzymatic Units (EU). The maximum values were observed in three strains of C. gattii from goats (EU > 12). The smallest values were observed in one environmental isolate of C. gattii serotype C (EU = 0.7). The highest recorded value for C. neoformans was 6.3 EU in a serotype A isolate from one human case of meningitis. C. gattii serotype B obtained from goats showed different degrees of laccase activity, being the highest in those isolated from severe outbreaks of cryptococcosis. This enzyme appears to represent a major, though nonexclusive, pathogenic factor for Cryptococcus gattii.

Laccase activity in Cryptococcus gattii strains isolated from goats

Cryptococcus neoformans y Cryptococcus gattii son los principales agentesde criptococosis, una grave micosis del hombre y los animales. Entre losfactores de patogenicidad de estas especies cabe destacar la lacasa(fenoloxidasa), enzima producida por éstas y otras especies fúngicas, queinduce la síntesis de melanina a partir de compuestos di-hidroxifenólicos.La gran mayoría de los numerosos estudios sobre la lacasa se han efectuadocon C. neoformans, y la información específica en C. gattii es muy escasa.El objetivo de este estudio ha sido evaluar la actividad de la lacasa enaislamientos de C. gattii serotipo B procedentes de cabrasinmunocompetentes muertas por criptococosis durante varios brotesepidémicos desarrollados en Cáceres (Extremadura, España).La producción de lacasa de estos aislamientos se ha comparado con la deotros de la misma especie y también con cepas de C. neoformans.Se procedió a la ruptura de las levaduras por métodos físicos, y elsobrenadante de cada aislamiento se añadió a una solución 20 mM de L-dopa. La actividad enzimática se midió a través de la absorbancia como unidadesenzimáticas (EU) a 450 nm. Los valores máximos de EU se observaron en trescepas de C. gattii aisladas de cabras (EU >12), mientras que el valor mas bajose observó en una cepa ambiental de C. gattii serotipo C (EU = 0,7).Para C. neoformans la mayor actividad lacasa se obtuvo en una cepa delserotipo A aislada en un paciente con meningitis criptocócica.Todos los aislamientos de C. gattii procedentes de los animales muertos enbrotes epidémicos mostraron diferentes grados de actividad lacasa.Esta enzima parece representar un factor de patogenicidad importante,aunque no exclusivo, en esta especie(au)

Cryptococcosis is a life-threatening infection in humans and animals causedby encapsulated yeasts of the genus Cryptococcus. Cryptococcus neoformansand Cryptococcus gattii are the main agents of this mycosis Until 2002C. gattii was classified as a variety of C. neoformans but now is accepted asan independent species. The laccase (phenoloxydase) enzyme produced bythese yeasts is considered one of the main pathogenic factors for its ability toinduce melanin from dihydroxyphenolic compounds. The vast majority of thestudies in laccase and melanin synthesis have been developed using isolatesof C. neoformans. The main objective of this study was to evaluate laccaseactivity in strains of C. gattii, serotype B isolated from immunocompetentgoats that died of lung and disseminated cryptococcosis, in several outbreaksoccurring in Spain. The laccase activities of these isolates were compared withthose of other strains of C. gattii and C. neoformans. After fungal cell rupture,the supernatant of each isolate was analyzed for its laccase activity using assubstrate an L-dopa 20 mM solution. The degree of enzymatic activity wasassessed according to its absorbance at 450 nm and scored using EnzymaticUnits (EU). The maximum values were observed in three strains of C. gattiifrom goats (EU > 12). The smallest values were observed in one environmentalisolate of C. gattii serotype C (EU = 0.7). The highest recorded value forC. neoformans was 6.3 EU in a serotype A isolate from one human case ofmeningitis. C. gattii serotype B obtained from goats showed different degreesof laccase activity, being the highest in those isolated from severe outbreaksof cryptococcosis. This enzyme appears to represent a major, thoughnonexclusive, pathogenic factor for Cryptococcus gattii(AU)