[Obtention of specific antisera for the serotyping of Cryptococcus neoformans var. neoformans]. / Obtención de antisueros específicos para la serotipificación de Cryptococcus neoformans var. neoformans.

The obtention of antisera at the Mycology Laboratory of "Pedro Kouri" Institute of Tropical Medicine was proposed to allow the rapid identification of the varieties and serotypes of Cryptococcus neoformans, since it is very important from the clinico-epidemiological point of view to know them. By immunizing rabbits with formalized whole cells of the 4 serotypes of this yeast, it was possible to obtain antisera that were absorbed with cells of the heterologous serotypes. 3 antisera capable of differentiating the neoformans var. (anti AD) and its respective serotypes (anti-A and anti-D) were attained. This paper will contribute to the knowledge of the epidemiology of this important disease in the Cuban setting for being the first time that useful antisera are obtained in Cuba to identify the serotypes corrresponding to the neoformans variety, which is the main causal agent of criptococcosis.

[Determination of morphotypes of Candida spp. in vaginal smears]. / Determinación de morfotipos de Candida spp en exudados vaginales.

Samples of vaginal smears were taken from 100 patients suspected of vaginal candidiasis that attended the Microbiology Laboratory of "Freyre de Andrade" Clinical and Surgical Hospital, in Havana City. These samples were cultivated in Sabouraud agar and Sabouraud triphenyltetrazolium agar (STA). In 45 % of the samples it was observed growth of the yeast-shaped colonies, where Candida albicans (51.1 %) and C. glabrata (22.2 %) were the most frequently isolated species. It was proved that STA allowed to differentiate the morphotypes of the yeast species and it was observed that most of the species presented more than one morphotype with the predominance of flat light pink colonies without mycelial halo in C. albicans, C. glabrata did not grow in it. This phenotypic typing in STA will permit to approach epidemiological studies in a future.

[In vitro sensitivity of Histoplasma capsulatum var. capsulatum to amphotericin B, ketoconazole, itroconazole and fluconazole]. / Sensibilidad in vitro de Histoplasma capsulatum var. capsulatum frente a anfotericina B, ketoconazol, itraconazol y fluconazol.

The minimum inhibitory concentration (MIC) was determined by a micromethod of dilution in RPMI-1640 broth in order to know the sensitivity to amphotericin B, itraconazole, ketoconazole and fluconazole of 29 strains of Histoplasma capsulatum var capsulatum isolated in Cuba. Histoplasmosis is one of the main systemic mycosis at the world level and its incidence has increased during the last years, associated mainly with HIV infection and to the appareance of new epidemic outbreaks in different regions. The results obtained allowed to conclude that high values of IMC against fluconazole were found with a geometric mean of 55.5 ug/mL. For amphotericin B, ketoconazole and itraconazole, all the strains were inhibited at low concentrations with geometric means of 0.26, 0.17 and 0.125 ug/mL, respectively. The development for the first time in Cuba of a method to determine the IMC of the main antifungal drugs against H. capsulatum var capsulatum will make possible to establish the sensitivity patterns and to detect the appearance of resistance, which will contribute to know this important mycosis better.

[Pigmentation of Cryptococcus neoformans strains on sunflower seed agar]. / Pigmentación de cepas de Cryptococcus neoformans sobre agar semilla de girasol.

The production of melanin on a medium of sunflower seeds extract agar from 86 strains of Cryptococcus neoformans belonging to the Mycology Laboratory of "Pedro Kouri" Institute of Tropical Medicine was determined. 54.7% of them produced colonies with dark brown pigment, 5.8% a light pigment and 37.2% an intermediate tonality. A fourth group was created for those strains with a true pigment (2.3%). This paper is an important contribution to attain a better characterization of the strains from the collection of the institution and serves as a basis to further studies of pathogenicity and susceptibility.

Sensibilidad de aislamientos clínicos de Candida albicans frente a la 5-fluorocitosina / Sensitivity of clinical isolates of Candida albicans to 5-fluorocytosine

5-fluorocytosine has been one of the most used antimycotics in the therapeutics of mycosis, however the appearance of resistant strains may be an important limitant for its use. That's why it is necessary to know the sensitivity to this drug. To this end, it was determined the minimum inhibitory concentration (MIC) of 5-fluorocytosine against 50 clinical isolates of Candida albicans by a micromethod of dilution in RPMI 1640 media, comparing 2 reading methods. The values of the geometrical mean obtained were 0.95 mg/mL for the visual reading and 0.75 mg/mL for the automated reading. There were no significant differences between them (p < 0.05). Pearson's lineal correlation coefficient was r = 0.81. It indicates that although there was a good correlation, there was also discrepancy between both readings. The IMC50 was of 0.5 microgram/mL and the IMC90 of 4 mg/mL. 90 and 92 of sensitive strains, between 6 and 8 of resistant strains and 2 of strains with intermediate sensitivity were found depending on the reading method used. These values show a low resistance against this drug, which may have a direct repercussion on the therapeutic behaviour to be followed in candidiasis.

Determinación de la concentración mínima inhibitoria de fluconazol frente a Cryptococcus neoformans / Determination of the minimum inhibitory concentration of fluconazole against Cryptococcus neoformans

The minimum inhibitory concentration of fluconozole was determined in 36 strains of Cryptococcus neoformans var. neoformans by a casitone broth microdilution method, taking into account that it is one of the most used antifungal agents in our country for the treatment of cryptococcal meningitis, the second opportunistic mycosis in order of frequency and that with the highest lethality among AIDS patients. The minimum inhibitory concentration of the studied strains ranged 0.125 to more than 64 micrograms/mL for a geometrical mean of 2.38 micrograms/mL. 50 of the strains were inhibited with 4 micrograms/mL and the least concentration that inhibited 90 was 16 micrograms/mL. It is stressed the importance of continuing this type of in vitro studies to detect the appearance of resistance of C. neoformans to antifungal agents.

Relacion entre la prueba intradermica de histoplasmina y los niveles de anticuerpos detectables por ELISA e immunodifusion / Relationship between histoplasmin skin test and Histoplasma capsulatum antibody levels detected by ELISA and immuno-diffusion tests

Se realizo un estudio prospectivo en 40 trabajadores de una granja avicola (grupo 1) considerados con riesgo de exposicion a Histoplasma capsulatum, agente etiologico de la histoplasmosis, y en 16 individuos sin riesgo profesional de exposicion a dicho agente (grupo 2). En ambos grupos se aplico la prueba intradermica de histoplasmina y se obtuvo el suero antes de su aplicacion y a los 30 y 180 dias despues de realizada dicha prueba...