Genotyping of Fusarium Isolates from Onychomycoses in Colombia: Detection of Two New Species Within the Fusarium solani Species Complex and In Vitro Antifungal Susceptibility Testing.

Fusariosis have been increasing in Colombia in recent years, but its epidemiology is poorly known. We have morphologically and molecularly characterized 89 isolates of Fusarium obtained between 2010 and 2012 in the cities of Bogotá and Medellín. Using a multi-locus sequence analysis of rDNA internal transcribed spacer, a fragment of the translation elongation factor 1-alpha (Tef-1α) and of the RNA-dependent polymerase subunit II (Rpb2) genes, we identified the phylogenetic species and circulating haplotypes. Since most of the isolates studied were from onychomycoses (nearly 90 %), we carried out an epidemiological study to determine the risk factors associated with such infections. Five phylogenetic species of the Fusarium solani species complex (FSSC), i.e., F. falciforme, F. keratoplasticum, F. lichenicola, F. petroliphilum, and FSSC 6 as well as two of the Fusarium oxysporum species complex (FOSC), i.e., FOSC 3 and FOSC 4, were identified. The most prevalent species were FOSC 3 (38.2%) followed by F. keratoplasticum (33.7%). In addition, our isolates were distributed into 23 haplotypes (14 into FOSC and nine into FSSC). Two of the FSSC phylogenetic species and two haplotypes of FSSC were not described before. Our results demonstrate that recipients of pedicure treatments have a lower probability of acquiring onychomycosis than those not receiving such treatments. The antifungal susceptibility of all the isolates to five clinically available agents showed that amphotericin B was the most active drug, while the azoles exhibited lower in vitro activity.

Fusarium species detected in onychomycosis in Colombia.

Fusarium spp. have frequently been isolated from patients with onychomycosis. In Colombia, several studies have shown that Fusarium is the most common non-dermatophyte mould causing onychomycosis and its spread has increased in the past years. In this study, samples were collected in 2003 and 2004 from 137 patients who were diagnosed with onychomycosis caused by Fusarium spp. Three species of Fusarium were identified: Fusarium solani (64.9%), Fusarium oxysporum (32.8%) and Fusarium verticillioides (2.3%). The diseases were more common in women (73%) than in men (27%) and occurred mainly among adults between 31 and 40 years old. The percentage of patients who had received previous treatments was 63.5%. In the last years, new and improved antifungal agents like echinocandins or new triazoles like voriconazole have been developed. For this reason, susceptibility testing using voriconazole was performed, by broth microdilution and disk diffusion. The results showed that F. solani had the highest minimum inhibitory concentration. Using the disk diffusion test, many of the isolates showed variable susceptibility. Genetic diversity of F. oxysporum isolates was determined by random amplified polymorphic DNA. Twenty isolates belonging to different haplotypes were selected for PCR amplification of a region of the gene encoding α-l-arabinofuranosidase B, a specific test to determine if the isolates were F. oxysporum f. sp. dianthi. On the basis of these PCR results, we found that five out of the 20 F. oxysporum isolates corresponded to f. sp. dianthi.

Malassezia yeast species isolated from patients with dermatologic lesions.

INTRODUCTION: Yeasts of the genus Malassezia form a normal component of skin flora, but are also associated with several dermatological disorders. Since 1996, the description of new species in this genus have led to new questions about their epidemiology and pathogenicity. OBJECTIVE: Herein, the frequency of Malassezia species in individuals with pityriasis versicolor, atopic dermatitis, seborrhoeic dermatitis, seborrhoeic dermatitis was compared in HIV patients and healthy individuals. Three body sites were selected for examination--head, thorax, and upper and lower extremities. MATERIAL AND METHODS: The 154 Malassezia species were isolated from 112 individuals and grouped as follows: 39 with seborrhoeic dermatitis (20 were HIV-positive patients), 18 with pityriasis versicolor, 18 with atopic dermatitis and 37 without dermatological leisions. HIV patient samples were examined microscopically, and specimens from both patients and healthy subjects were cultured on modified Dixon agar medium. Subsequently, isolates were identified by macroscopic, microscopic and physiological characteristics. RESULTS: The most commonly isolated species were Malassezia globosa (37.5%), M. sympodialis (31.3%) and M. furfur (31.3%). Malazzerzia globosa predominated in patients with pityriasis versicolor (67%) and in HIV-positive patients with seborrhoeic dermatitis (85%). In non-HIV patients with atopic dermatitis or seborrhoeic dermatitis, M. furfur and M. restricta were isolated in 72% and 26% of the cases, respectively. CONCLUSION: Several conclusions were evident. First, Malassezia species was present in subjects with and without dermatological pathologies. Second, the species frequency in the sampled population differed from frequencies reported from other geographic areas. Third, Malassezia globosa was involved at high frequency in patients with dermatological pathologies, suggesting a higher pathogenicity of this species. Additional studies on each species are recommended to clarify their pathogenic roles in association with HIV-positive and normal subjects.

Malassezia yeast species isolated from patients with dermatologic lesions / Especies de Malassezia aisladas de pacientes con lesiones dermatológicas

Introducción. Las levaduras del género Malassezia forman parte de la flora normal de la piel y se asocian con varios tipos de lesiones dermatológicas. Desde 1996, la descripción de nuevas especies dentro de este género planteó numerosos interrogantes sobre su epidemiología y patogenicidad. Objetivo. El fin de este trabajo fue encontrar la frecuencia de las diferentes especies de Malassezia en individuos con pitiriasis versicolor, dermatitis atópica, dermatitis seborreica, dermatitis seborreica en pacientes positivos para VIH, y en individuos sin lesiones a partir de tres zonas corporales (cabeza, tórax, extremidades inferiores y superiores). Materiales y métodos. Se identificaron 154 aislamientos de especies de Malassezia de 112 individuos: 39 con dermatitis seborreica de los cuales 20 eran positivos para VIH, 18 con pitiriasis versicolor, 18 con dermatitis atópica y 37 individuos sin lesión dermatológica (controles). Las escamas de piel de los pacientes se observaron microscópicamente y las muestras de pacientes y controles se cultivaron en agar Dixon modificado. Posteriormente, se observaron las colonias y se identificaron según sus características macroscópicas, microscópicas y fisiológicas. Resultados. Las especies más frecuentemente aisladas en el total de los grupos estudiados fueron: Malassezia globosa (37,5 por ciento), M. sympodialis (31,3 por ciento) y M. furfur (31,3 por ciento). M. globosa predominó en los aislamientos de pacientes con pitiriasis versicolor (67 por ciento) y en pacientes positivos para VIH con dermatitis seborreica (85 por ciento). En pacientes con dermatitis atópica y dermatitis seborreica sin diagnóstico de VIH, se aislaron M. furfur y M. restricta en el 72 por ciento y el 26 por ciento de los casos, respectivamente. Conclusiones. Las diferentes especies de Malassezia pueden aislarse de pacientes con lesiones dermatológicas o sin ellas. Además, la frecuencia de especies en la población muestreada difiere de lo reportado en otras zonas geográficas. Se destaca la alta frecuencia de M. globosa en pacientes con lesiones lo que podría indicar la mayor patogenicidad de esta especie. No obstante, se requieren estudios adicionales para determinar el papel de las diferentes especies del género Malassezia, asociadas con estas patologías