Sabouraudia最新文献

Thirteen resistogram strains of Candida albicans were found among isolates obtained from the mouth and cutaneous sites of irradiation of 27 patients receiving treatment for oral and laryngeal cancer. In all cases the yeast was recovered from the mouth before treatment, but not from the skin site until after treatment had begun. Of the 27 patients, 25 harboured one or more strains with identical resistograms in both sites.

Mycotic keratoconjuntivitis caused by Acremonium kiliense in a German Shepherd bitch was diagnosed with the aid of laboratory tests. The dog presented with photophobia, tearing, corneal edema and reduction of the visual capacity. A thick white layer partially covered the right eye. The left eye showed irritation and small brown stains which were diagnosed as pigmentary keratitis. The initial treatment consisted of 2% yellow mercury oxide. Natamycin was used as final treatment. Seven days later, the natural brightness of the eye as well as the visual capacity were restored.

Scanning electron microscopy of four different Paracoccidioides brasiliensis isolates in the yeast phase revealed that mother cells generating multiple, spherically shaped buds may be firmly or tenuously associated with their progeny whereas elongated buds remain attached to the mother cell through stem-like structures and may represent early stages of hypha formation. The yeast cell surfaces were covered with a delicate network of microfibrillar components.

Several antifungal agents, at concentrations of 10 micrograms/ml, were shown to suppress ATP concentrations very rapidly in intact cells and spheroplasts of Candida albicans. The highest ATP-suppressing activity was shown by the highly lipophilic imidazole derivatives difonazole, clotrimazole, econazole, isoconazole, miconazole, oxiconazole and tioconazole, which all caused a reduction of cellular ATP content of more than 50% in 10 min. Relatively hydrophilic imidazole derivatives such as ketoconazole were essentially inactive in the test, as were the triazole derivatives fluconazole, ICI 153066, itraconazole and terconazole, and 5-fluorocytosine. Amphotericin B and terbinafine possessed intermediate ATP-suppressing activity, and the dose-response and pH-response curves for these compounds suggested their mechanism of ATP suppression differed from that of the active imidazole derivatives. ATP suppression by azole antifungals did not involve leakage of ATP from the cells and the effect was entirely abrogated by the presence of serum. Intact cells and spheroplasts of yeast-form and hyphal-form C. albicans were generally equally sensitive to ATP suppression, but stationary-phase cells of both morphological forms were less sensitive than exponential-phase cells. The extent of ATP suppression was significantly reduced in stationary-phase yeast cells of a C. albicans strain with known resistance to azole antifungals, but exponential-phase cells of resistant and susceptible strains were equally sensitive. The effect is tentatively ascribed to membrane damage caused directly by the antifungals.

The mole per cent guanine plus cytosine was determined for DNA extracted from Coccidioides immitis to add information pertinent to the taxonomy of this zoopathogenic fungus. Four strains of C. immitis, three in the mycelial phase, one in the spherule/endospore phase yielded guanine plus cytosine in the narrow range of 49.41 to 49.61 mole percent. These values are lower than those for ascomycetes that mimic the arthroconidial form of C. immitis, higher than those for ascomycetous yeasts, but closer to those of 'transition zone' or basidiomycetous yeasts.

The sporulation capacities of the mycelial form of Paracoccidioides brasiliensis were determined. Five different culture media were used and four human isolates studied. Conidia were produced in three agar media, namely water-agar, glucose-salts and yeast-extract. Corn meal and Sabouraud dextrose agars failed to induce sporulation. Various types of spores were characterized with peculiar bulging arthroconidia and single-celled, pear-shaped conidia predominating. The size of these conidia varied from 3.6 to 4.6 micron in length. It is concluded that the mycelial form of P. brasiliensis produces characteristic spores if the proper culture media are employed.

Fatal pulmonary infection in a captive alligator (Alligator mississippiensis) is reported. At necropsy, the animal appeared to be in excellent nutritional condition, but a severe necrotizing bronchitis with bronchiectasis was present. Histological examination revealed numerous branched, septate, hyaline hyphae within the necrotic debris lining the bronchi and rarely infiltrating into the adjacent stroma. The fungus cultured from the lung was identified as F. moniliforme.

The antifungal antibiotic, ambruticin, inhibits growth of Candida parapsilosis and reduces its ability to take up amino acids. Increasing growth temperature from 30 degrees C to 39 degrees C leads to a 100-fold decrease in the minimum growth inhibitory concentration. Ambruticin is 20 times more effective at pH 5 than at pH 8 and exponentially growing cultures are much less susceptible than stationary phase cells. The activity of ambruticin is also dependent on the presence of certain exogenous nutrients. When acetate or succinate (10 mM) are included in the incubation medium, ambruticin has little effect on amino acid uptake. Glucose, mannose and glycerol do not decrease the efficacy of ambruticin. Ambruticin probably inhibits growth by reducing the utilization of exogenous and intracellular carbohydrates. This leads to a fall in energy production within the cell which can be monitored as a reduction in the activity of energy-dependent transport systems.

The effect of the imidazole oxiconazole and the morpholine derivative Ro 14-4767/002 on the sterol metabolism of Candida albicans was investigated at different periods of growth. Ergosterol, representing the main sterol component of control cells, was markedly reduced in oxiconazole-treated and Ro 14-4767/002-treated cells. However, the total sterol content of the cells treated with both drugs was increased due to accumulation of other sterols not present in control cells: in oxiconazole-treated cells 24-methenedihydrolanosterol, 4,14-dimethylfecosterol and 14-methylfecosterol accumulated, indicating an inhibition of C14-demethylation. This is in agreement with the mode of action described for other azoles in various pathogen fungi. In Ro 14-4767/002-treated cells the main sterol accumulated was ignosterol, indicating an inhibition of delta 14-sterol reductase and delta 8-delta 7-isomerase. This inhibition has not been described before in human pathogens although it has been previously found in plant pathogenic fungi treated with fenpropimorph.