[Causal agents of onychomycosis]. / Agentes causales de onicomicosis.

The results obtained with 307 specimens from putatively immunocompetent patients between May 1991 and May 1992 were reviewed, to determine the frequency of isolation of fungal species causing onychomycoses. Sixty eight percent of the specimen were positive for microscopic examination and/or cultures. Onychomycoses occurred with double frequency in women than in men (Table 1), and 77% of cases were diagnosed in patients aged between 30 and 70 years (Figure 1). Out of 182 patients with positive cultures, 60% were affected by dermatophytes and 39% by yeasts; molds (Aspergillus spp.) were isolated in only two cases (Table 3). Neither Corynebacterium spp., nor Malasezzia furfur were detected. In toe nails Trichophyton rubrum predominated over yeasts being isolated in 72.9% of the cases; yeasts other than Candida albicans were isolated in 12.3%, Trichophyton mentagrophytes in 10%, while Aspergillus spp., C. albicans and Epidermophyton floccosum in only 1.6%. On the other hand, in finger nails yeasts predominated: C. albicans was isolated in 46.7% of cases, other yeasts in 43.3%; and T. rubrum in the remaining 10%. Out of 41 isolations of yeasts other than C. albicans, 42% were C. parapsilosis, 16% Debaryomyces hansenii, 6% C. pulcherrima, 6% Trichosporum cutaneum and 6% C. famata (Figure 2).

[Incidence of various etiologic agents of superficial mycosis]. / Incidencia de los distintos agentes etiológicos de micosis superficiales.

In a retrospective review of laboratory records at the Department of Mycology, National Institute of Microbiology "Dr. Carlos G. Malbrán", during the period June 1989-July 1991, 1225 putatively immunocompetent cases of superficial mycoses were identified. Ninety five percent of these patients were adults and 5% children. Among the total cases, dermatomycoses were caused, 67.6% by dermatophytes, 25.9% by yeasts, 5.9% by Malassezia furfur. and 0.5% by other fungi, as proven by the isolation of the etiological agents. (Figure 1, Table 2). Among the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes greatly predominated accounting for 66.6% and 20.0% of the isolates, respectively, whereas Microsporum canis (8.0%). Epidermophyton floccosum (5.1%) and Microsporum gypseum (0.3%) were found with less frequency (Figure 2). Nails (47%) were the most common source of isolates in adults, followed by feet (28%), smooth skin (15%), groin (5%) and hands (2%) (Table 1). Regarding the relative efficiency of the diagnostic methods, the analyses of laboratory results evidenced that, 98% of the cases with clinical findings compatible with mycoses and 76% of the cases with positive cultures (Table 1) were identified by microscopic observation.

[In vitro sensitivity tests for yeasts: evaluation of a micromethod]. / Pruebas de sensibilidad in vitro para levaduras: evaluación de un micrométodo.

A microdilution antifungal susceptibility test for yeasts was evaluated, based on the macro broth dilution method standardized by the National Committee for Clinical Laboratory Standards (NCCLS) Subcommittee on Antifungal Susceptibility Testing. Both methods were compared using six reference strains with different patterns of susceptibility to the following antifungal drugs: amphotericin B (AMB), flucytosine (5FC), fluconazole (FCZ), itraconazole (ITZ), ketoconazole (KTZ) and miconazole (MCZ). Minimal inhibitory concentration (MIC) results obtained by both methods differed only in 1 or 2 dilutions. Microdilution MIC's determined as visual endpoints and as quantitative measurement of 80% inhibition of relative growth showed a significant correlation (p < 0.001) for AMB, 5FC, FCZ, MCZ and ITZ, conversely no correlation (p = 1.00) for KTZ was observed as determined with 47 local isolates of Candida albicans.

Agentes causales de onicomicosis / [Causal agents of onychomycosis]

The results obtained with 307 specimens from putatively immunocompetent patients between May 1991 and May 1992 were reviewed, to determine the frequency of isolation of fungal species causing onychomycoses. Sixty eight percent of the specimen were positive for microscopic examination and/or cultures. Onychomycoses occurred with double frequency in women than in men (Table 1), and 77

of cases were diagnosed in patients aged between 30 and 70 years (Figure 1). Out of 182 patients with positive cultures, 60

were affected by dermatophytes and 39

by yeasts; molds (Aspergillus spp.) were isolated in only two cases (Table 3). Neither Corynebacterium spp., nor Malasezzia furfur were detected. In toe nails Trichophyton rubrum predominated over yeasts being isolated in 72.9

of the cases; yeasts other than Candida albicans were isolated in 12.3

, Trichophyton mentagrophytes in 10

, while Aspergillus spp., C. albicans and Epidermophyton floccosum in only 1.6

. On the other hand, in finger nails yeasts predominated: C. albicans was isolated in 46.7

of cases, other yeasts in 43.3

; and T. rubrum in the remaining 10

. Out of 41 isolations of yeasts other than C. albicans, 42

Trichosporum cutaneum and 6

Incidencia de los distintos agentes etiológicos de micosis superficiales / [Incidence of various etiologic agents of superficial mycosis]

In a retrospective review of laboratory records at the Department of Mycology, National Institute of Microbiology [quot ]Dr. Carlos G. Malbrán[quot ], during the period June 1989-July 1991, 1225 putatively immunocompetent cases of superficial mycoses were identified. Ninety five percent of these patients were adults and 5

children. Among the total cases, dermatomycoses were caused, 67.6

by Malassezia furfur. and 0.5

by other fungi, as proven by the isolation of the etiological agents. (Figure 1, Table 2). Among the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes greatly predominated accounting for 66.6

of the isolates, respectively, whereas Microsporum canis (8.0

) and Microsporum gypseum (0.3

) were found with less frequency (Figure 2). Nails (47

) were the most common source of isolates in adults, followed by feet (28

) and hands (2

) (Table 1). Regarding the relative efficiency of the diagnostic methods, the analyses of laboratory results evidenced that, 98

of the cases with clinical findings compatible with mycoses and 76

of the cases with positive cultures (Table 1) were identified by microscopic observation.

Pruebas de sensibilidad in vitro para levaduras: evaluación de un micrométodo / In vitro susceptibility tests for yeasts: evaluation of a micromethod

Se evaluó un micrométodo para la realización de pruebas de sensibilidad de levaduras frente a antifúngicos, basado en el macrométodo en medio líquido estandarizado por el National Committee for Clinical Laboratory Standards (NCCLS) Subcommittee on Antifungal Susceptibility Testing. En este trabajo se compararon ambos métodos utilizando 6 cepas de referencia de diferente sensibilidad a los siguientes antifúngicos, anfotericina B (AMB), flucitosina (5FC), fluconazol (FCZ), itraconazol (ITZ), ketoconazol (KTZ) y miconazol (MCZ). Se observaron variaciones de sólo 1 ó 2 diluciones entre los resultados de las concentraciones inhibitorias mínimas (CIM) obtenidas con las dos técnicas. Asimismo, se compararon las lecturas visuales de CIM por micrométodo con las mediciones turbidimétricas del crecimiento en distintas concentraciones de antifúngicos frente a 47 aislamientos de Candida albicans. Existió una correlación significativa (p<0.001) entre CIM visual y la inhibición del 80 por ciento de crecimiento determinada por turbidimetría con AMB, 5FC, FCZ, ITZ y MCZ; en cambio no hubo correlación alguna para KTZ (p=1.00)