Oral yeast carriage in HIV-infected and non-infected populations in Rosario, Argentina.

The objectives of the present study were: (i) to assess the frequency of oral colonisation by Candida species in HIV-positive patients and to compare it with a population of HIV-negative individuals, (ii) to determine the prevalence of C. dubliniensis in both populations and (iii) to determine the susceptibility of C. dubliniensis and other Candida species isolated from HIV-positive patients to the most commonly used antifungal agents. Oral samples were obtained from 101 HIV-positive and 108 HIV-negative subjects. For yeast identification, we used morphology in cornmeal agar, the API 20C Aux, growth at 45 degrees C, d-xylose assimilation, morphology in sunflower seed agar and PCR. The frequency of isolation of Candida in HIV-positive patients was: C. albicans, 60.7%; C. dubliniensis, 20.2%; C. glabrata, 5.6%; C. krusei, 5.6%; C. tropicalis, 4.5%; others, <5%. The frequency of isolation of Candida in HIV-negative patients was: C. albicans, 73.9%; C. tropicalis, 15.5%; C. dubliniensis, 2.1%; C. glabrata, 2.1%; C. parapsilosis, 2.1%; others, <5%. The oral colonisation by yeast in the HIV-positive patients was higher than that in the HIV-negative subjects. The susceptibilities of 42 Candida isolates to three antifungal agents were determined. All isolates of C. dubliniensis were susceptible to fluconazole, although several individuals had been previously treated with this drug. Out of the 42 Candida isolates, 10 presented resistance to fluconazole and 10 to itraconazole. The presence of Candida species, resistant to commonly used antifungal agents, represents a potential risk in immunocompromised patients.

Recent Outbreak of Soybean Sudden Death Syndrome Caused by Fusarium virguliforme and F. tucumaniae in Argentina.

Sudden death syndrome (SDS) of soybean was detected initially in Argentina during 1991-1992 in the Pampas Region and 1992-1993 in the Northwest Region. The first report of the fulfillment of Koch's postulates of SDS caused by Fusarium solani f. sp. glycines in Argentina was published in 2003 (3). Subsequently, analyses have shown that F. solani f. sp. glycines represents several morphologically and phylogenetically distinct species, including F. tucumaniae in Argentina and F. virguliforme in the United States (1). Isolations were made from plants that exhibited typical SDS symptoms (interveinal foliar chlorosis and necrosis leading to defoliation of the leaflets but not the petioles) from fields in Santa Fe and Buenos Aires provinces in 2001, 2002, and 2003. To determine which species are responsible for SDS in Argentina, cultures of eight slow growing isolates that developed bluish pigmentation and produced abundant macroconidia in sporodochia on potato dextrose agar were subjected to morphological and molecular phylogenetic analyses and pathogenicity tests. Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae. Isolates of F. tucumaniae produced long and narrow sporodochial conidia while F. virguliforme produced diagnostic comma-shaped conidia. Molecular phylogenetic analyses of DNA sequences from multiple loci confirmed morphology-based identifications and showed that the soybean SDS pathogen in the United States, F. virguliforme, was also present in Argentina. To our knowledge, this is the first report of F. virguliforme in Argentina and of this pathogen outside the United States. Five isolates of F. tucumaniae and three isolates of F. virguliforme were used for pathogenicity tests. F. virguliforme isolate 171 provided by J. Rupe (University of Arkansas, Fayetteville) was used as a positive control. Soybean cultivars Ripley, RA 702, Pioneer 9492RR, Spencer, and A-6445RG were inoculated with each of the isolates tested in a greenhouse assay using soil infestation and toothpick methods (2). All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation. Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control using a disease severity scale in which 1 = no symptoms and 5 = severely infected or dead plants. Under these conditions, F. virguliforme appeared to be more virulent than F tucumaniae. Noninoculated plants remained symptomless. Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG. Isolates recovered from symptomatic plants inoculated by the soil infestation and toothpick methods were identical to those used to inoculate the plant. Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively. To our knowledge, this is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina. References: (1) T. Aoki et al. Mycologia 95:660, 2003. (2) K. W. Roy et al. Plant Dis. 81:1100, 1997 (3) M. Scandiani et al. Plant Dis. 87:447, 2003.

Adherence of Candida strains isolated from the human gastrointestinal tract.

The adherence of different Candida strains isolated from the human gastrointestinal tract was studied. The 23 Candida strains isolated from faeces were C. albicans (12), C. glabrata (2), C. krusei (2), C. parapsilosis (2), C. tropicalis (2), C. colliculosa (1), C. kefyr (1) and C. lusitaniae (1). Buccal epithelial cells from different healthy donors were used. Adherence values were maximal for C. albicans and minimal for C. krusei. A relation exists between yeast adherence capacity and the ability to colonize mucosal surfaces.

[Influence of temperature and pH on the in vitro adherence of Candida albicans.]. / Efecto de la temperatura y el pH en la adherencia de Candida albicans in vitro.

Yeast adherence to epithelial cells is a very important step in colonization and infection caused by these opportunistic pathogens. This phenomenon may be modified in vitro by many factors. The aim of this work was to find out how variations in pH and temperature modify the in vitro adherence of Candida albicans to epithelial cells. We worked with epithelial buccal cells and a yeast strain according to Gibbons and Van Houte technique with slight modifications. In the first assay, adherence at 28 degrees C and 37 degrees C, and three pH values, 6, 7.2 and 8.4 were simultaneously studied. We did not find significant variations in adherente capacity, but a slight increase was detected at pH 7.2 and 37 degrees C. In the second assay, temperature was fixed at 37 degrees C and four pH values were studied: 3, 4, 5, and 7.2. We find a highly significant difference (p < 0.001) between adherente at pH = 7.2 with respect to the other pH values. According to these results C. albicans adherence to epithelial buccal cells, in vitro, is produced at 37 degrees C and pH 7.2 in optimal conditions.

Estudio de una cepa de Cryptococcus Neoformans pobremente capsulada, en un paciente con SIDA / Fungal meningitis (Cryptococcus neoformans) in a male patient with AIDS

Se estudió la cepa de Cryptococcus neoformans var. neoformans aislada de LCR de un paciente con SIDA. Con el material se realizaron exámenes directos con tinta china, cultivos y prueba de aglutinación de partículas de látex sensibilizadas. La cepa aislada se identificó mediante auxanograma de hidratos de carbono, pruebas de ureasa y de Salkin. Con el fin de estimular la producción de la cápsula se la sembró en agar chocolate y se la inoculó en ratones Rockland por vías intracraneal e intraperitoneal. Se observó que la cepa era pobremente capsulada en los exámenes directos y pobremente capsulada en los cultivos. Se observó el mayor tamaño de su cápsula en el examen directo del cerebro del ratón. La presentación de cepas pobremente capsuladas en pacientes inmunosuprimidos ya fue observada por otros autores. Se postula la posibilidad que, en estos pacientes, el grado de inmunodeficiencia pueda afectar la infectividad y patogenicidad de estas variedades de C. neoformans

Estudio de una cepa de Cryptococcus Neoformans pobremente capsulada, en un paciente con SIDA / Fungal meningitis (Cryptococcus neoformans) in a male patient with AIDS

Se estudió la cepa de Cryptococcus neoformans var. neoformans aislada de LCR de un paciente con SIDA. Con el material se realizaron exámenes directos con tinta china, cultivos y prueba de aglutinación de partículas de látex sensibilizadas. La cepa aislada se identificó mediante auxanograma de hidratos de carbono, pruebas de ureasa y de Salkin. Con el fin de estimular la producción de la cápsula se la sembró en agar chocolate y se la inoculó en ratones Rockland por vías intracraneal e intraperitoneal. Se observó que la cepa era pobremente capsulada en los exámenes directos y pobremente capsulada en los cultivos. Se observó el mayor tamaño de su cápsula en el examen directo del cerebro del ratón. La presentación de cepas pobremente capsuladas en pacientes inmunosuprimidos ya fue observada por otros autores. Se postula la posibilidad que, en estos pacientes, el grado de inmunodeficiencia pueda afectar la infectividad y patogenicidad de estas variedades de C. neoformans

Diagnóstico de 2 casos de mucormicosis rino-facio-cerebral en pacientes diabeticos / Diagnosis two cases de rhino-facio-cerebral mucomycosis in diabetic patients

Se presentan dos casos de mucormicosis rino-facio-cerebral de evolución lenta, en pacientes diabéticos. El diagnóstico se realizó por el hallazgo del hongo en el exámen histopatológico y exámenes microcópicos de los materiales drenados de los senos maxilares, que mostraron hifas no septadas y abundantes. En ninguno de los casos se pudo recuperar el agente etiológico por cultivo, debido a la labilidad de los mucorales y por la presencia de un material necrótico de fácil contaminación microbiana

Diagnóstico de 2 casos de mucormicosis rino-facio-cerebral en pacientes diabeticos / Diagnosis two cases de rhino-facio-cerebral mucomycosis in diabetic patients

Se presentan dos casos de mucormicosis rino-facio-cerebral de evolución lenta, en pacientes diabéticos. El diagnóstico se realizó por el hallazgo del hongo en el exámen histopatológico y exámenes microcópicos de los materiales drenados de los senos maxilares, que mostraron hifas no septadas y abundantes. En ninguno de los casos se pudo recuperar el agente etiológico por cultivo, debido a la labilidad de los mucorales y por la presencia de un material necrótico de fácil contaminación microbiana

Endoftalmitis por Aspergillus nidulans / Endophtalmitis due to Aspergillus nidulans

Se comunica un caso de endoftalmitis micótica del ojo izquierdo en un paciente de 18 años, que había sufrido una herida perforante en ese ojo con posterior tratamiento antibiótico y corticoídeo. Del material de la cámara anterior del ojo, se aisló Aspergillus nidulans. El paciente fue tratado con natamicina y evolucionó favorablemente (AU)

Endoftalmitis por Aspergillus nidulans / Endophtalmitis due to Aspergillus nidulans

Se comunica un caso de endoftalmitis micótica del ojo izquierdo en un paciente de 18 años, que había sufrido una herida perforante en ese ojo con posterior tratamiento antibiótico y corticoídeo. Del material de la cámara anterior del ojo, se aisló Aspergillus nidulans. El paciente fue tratado con natamicina y evolucionó favorablemente

Study of a Madurella grisea strain isolated from a foot mycetoma.

Madurella grisea has been isolated from a Madura foot with black grains. The fungi classification was made based on the macro and micro-morphology characteristics of the culture. Difficulties with the interpretation of biochemistry tests were analyzed. The study is completed with trials of in vitro sensibility for different antifungal agents.