Biomedical subjects

G Davel

Publications and source records attributed to G Davel.

23 records · Page 2Linked to original sources

PubMedDate not supplied

[Histoplasma capsulatum with aberrant morphology isolated in Argentina].

For the first time in Argentina, we describe a strain of Histoplasma capsulatum var. capsulatum with an aberrant morphology that was isolated from a single patient with AIDS. Mycelial phase cultures on agar Sabouraud at 25-28 degrees C showed white, glabrous, umbilicated and centrally radiated colonies. Unusual microscopic findings were the absence of typical conidia, the presence of terminal/intercalary chlamydoconidia with a diameter of 4 pm and of thickened hyphae. Fungal identification was confirmed by the detection of bands H and M species specific antigens in mycelial culture supernatants and reversion to the typical yeast phase on agar brain-heart-cysteine at 37 degrees C. The genomic DNA profile obtained by RAPD-PCR with primers 1281-1283 coincided with the predominant profile of H. capsulatum among isolates from Argentine patients.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

[Disk diffusion method for fluconazole susceptibility testing of Candida spp. isolates].

In order to standardize and evaluate a disk diffusion method with visual reading to detect in vitro fluconazole susceptibility of yeast, 1193 clinical isolates were tested. These included 584 Candida albicans, 196 Candida parapsilosis, 200 Candida tropicalis, 113 Candida glabrata, 50 Candida krusei and 50 Candida spp. and other opportunistic yeasts. The disks were manufactured in the INEI-ANLIS "Dr. Carlos G. Malbrán. The disk diffusion method results were compared to MIC results obtained by the reference CLSI M27-A2 broth microdilution method modified by EUCAST. The interpretative breakpoints for in vitro susceptibility testing of fluconazole were established at: zone diameter > or =16 mm for MIC < or =8 microg/ml (susceptible isolates), between 9 and 15 mm for MIC = 16-32 microg/ml (susceptible dose-dependent isolates), and < or =8 mm for MIC > or =64 microg/ml (resistant isolates). Overall agreement between the two methods was 94.7%, with 0.2% very major errors, and 0.3% major errors. Inter - and intralaboratory agreement was good. The disk diffusion method for drug susceptibility testing of Candida spp. isolates is inexpensive, reliable and reproducible. However, when the inhibition zone diameter is < or =15 mm, it is advisable to test the isolate by the reference microdilution method.

Antifungal Agents↗

PubMedDate not supplied

[Yeast infections: causative agents and their antifungal resistance in hospitalized pediatric patients and HIV-positive adults].

Candidiasis has increased its frequency over the last decade, particularly among hospitalized patients where it is accompanied with high rates of mortality, and in patients with AIDS who are predisposed to oropharyngeal or esophageal candidiasis. The aim of this study was to determine the frequency of appearance of different yeast species and the resistance profile to current antifungal drugs in hospitalized pediatric patients and adult HIV patients from 5 institutions of Buenos Aires City and suburbs, and La Plata City, during the period 1993-1995, in order to obtain local and updated information. Candida albicans was the etiologic agent recovered in 87% of the 214 HIV positive patients with oropharyngeal candidosis, and in 50% of the 209 hospitalized pediatric patients. In the latter group 28% of these infections were due to Candida parapsilosis and 18% to Candida tropicalis, but only 2% and 4% of oral candidosis were caused by these organisms. Detection of Malassezia furfur and Hansenula anomala, responsible of systemic infections, and Trichosporon beigelii, isolated from a burn patient, were considered remarkable since these organisms appear to be emerging pathogens. Azole resistant species as Candida krusei and C. glabrata were mostly recovered from HIV positive patients, exposed to fluconazole treatment. A very low number of amfotericin B "resistant" yeasts (n = 9) were observed in both groups. However, resistance to azole drugs, particularly to fluconazole, was found in pediatric patients (13%) and in HIV infected adults (34%).

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

[Candida dubliniensis: 1st isolation in Argentina].

We report the first isolation of Candida dubliniensis in Argentina. This strain was isolated from an oral lesion of an adult patient with AIDS during one recurrent episode of a previously treated oropharingeal candidosis. Phenotypic and genotypic characteristics coincided with those described by Sullivan et al., who was the first to study this new species.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

[Specific fungal antisera production in rabbits].

A method for fungic antisera production against Aspergillus fumigatus, Histoplasma capsulatum, Paracoccidioides brasiliensis and Coccidioides immitis in rabbits was evaluated. Intradermic via and antigen in the dilution used for routine tests (UD) were employed to produce positive control serum for immunodiffusion test in agar gel. A. fumigatus, H. capsulatum and C. immitis antigens were prepared as described in CDC's Procedure Manual, P. brasiliensis antigen was prepared as previously described by Pires de Camargo. All rabbits produced antibodies against the different specific antigens in the primary response peak and after each booster. The titer obtained in secondary response was similar or smaller than the primary response in all cases. However, bands of similar quality and intensity were obtained by immunoprecipitation in agar gel tests. Although the antibody titers proved to be similar, higher or lower concentration of antigen used in the primary immunization produced fewer and smeared bands, respectively. This effect was evaluated in A. fumigatus only. Specific antisera production with this method proved to be easy and yielded high quality antisera. The major advantages of this method are: a) reduced number of inoculations, b) fast and simple standardisation of the antigen needed, c) equally useful for all the fungal species used so far. Therefore we strongly recommend this method.

Animals↗