RESUMO
Candida auris is considered a public health problem due to its resistance and its tendency to cause nosocomial outbreaks. CHROMagarTMCandida Plus has recently been marketed as capable of presumptively identifying C. auris. The objective of this work was to analyze the ability of this new chromogenic medium to differentiate C. auris from other members of the C. haemulonii complex and from other yeasts commonly isolated in clinical practice. A collection of 220 strains including species of the C. haemulonii (n = 83) and C. parapsilosis (n = 80) complexes was studied. The strains were identified by molecular methods and cultured as individual or as mixed aqueous inoculum on CHROMagarTMCandida Plus plates. Colony morphotypes were evaluated at 5 time points. CHROMagarTMCandida Plus was a helpful tool for presumptive identification for C. auris. Better reading results were obtained after 48 hours of incubation at 35°C. It is able to easily differentiate C. auris from other closely related species of the C. haemulonii complex and other yeasts. This chromogenic medium would be also useful as screening and surveillance tool for C. auris colonization. However, we demonstrated that it would be a possible misidentification of C. parapsilosis as C. auris (44.3% showed similar morphotypes). To reduce false positives when it is used in a context of a C. auris outbreak, we propose to supplement the chromogenic medium with 8 µg/ml fluconazole. This modified medium was tested and it clearly differentiate C. parapsilosis from C. auris.
CHROMagarTMCandida Plus is able to differentiate C. auris from other Candida spp., including other species of the C. haemulonii complex. However, 44.3% of the tested C. parapsilosis strains would be misidentified as C. auris. We propose the addition of 8 µg/ml fluconazole to solve this issue.
RESUMO
Leaf blight and purple seed, caused by the fungal pathogen Cercospora kikuchii (Matsumoto & Tomoyasu) M. W. Gardner are very important diseases of soybean (Glycine max L. Merr.) in Argentina. The aims of this work were: (a) to confirm and to assess the genetic variability among C. kikuchii isolates collected from different soybean growing areas in Santa Fe province using inter simple sequence repeats (ISSR) markers and sequence information from the internal transcribed spacer (ITS) region of rDNA and (b) to analyze the cercosporin production of the regional C. kikuchi isolates in order to assess whether there was any relationship between the molecular profiles and the toxin production. Isolates from different regions in Santa Fe province were studied. The sequence of the ITS regions showed high similarity (99-100%) to the GenBank sequences of C. kikuchii BRCK179 (accession number AY633838). The ISSR markers clustered all the isolates into many groups and cercosporin content was highly variable among isolates. No relationship was observed between ITS region, ISSR groups and origin or cercosporin content. The high degree of genetic variability and cercosporin production among isolates compared in this study characterizes a diverse population of C. kikuchii in the region.
Assuntos
Ascomicetos/genética , Ascomicetos/metabolismo , Variação Genética , Glycine max/microbiologia , Perileno/análogos & derivados , Argentina , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Sequência de Bases , Dados de Sequência Molecular , Perileno/metabolismo , Filogenia , Glycine max/crescimento & desenvolvimentoRESUMO
The aims of the present study were to analyze the genetic variability of Cercospora kikuchii isolates and the in vitro cercosporin production, of these isolates obtained from soybean at the central-northern region of Santa Fe province (Argentina). Also the relationship between RAPD profiles and toxin production was also assessed. The strain C. kikuchii NBRC 6711 and 13 soybean isolates with symptoms of leaf blight were tested. Cercosporin production was analyzed by growing the fungus on Potato Dextrose Agar, extracting the toxin in alkaline medium and determining its concentration by spectrophotometry. The population of C. kikuchii studied showed variability, both genotypically, nine different groups were encountered, and have the ability to produce cercosporin. No relationship was found between toxin production and the RAPD profiles.