High frequency of potentially pathogenic yeast species in goat’s raw milk and creamed cheese in Southern Brazil

There are few reports concerning isolation, counting and identification of yeasts in goat´s raw milk and derivates. The objective of this study was to evaluate the diversity of yeasts found in raw goat milk and goat creamed cheese collected in a Metropolitan area in Porto Alegre - Brazil. A simplified HMA (Heteroduplex Mobility Assay) of the 26S rDNA D1/D2 region was developed in order to rapidly confirm the identification of the isolates belonging to potentially pathogenic species. Yeasts were isolated from 59% of the samples. Fifty six strains were isolated and identified in the genera Bullera, Candida, Cryptococcus, Debaryomyces, Dekkera, Pichia, Rhodotorula, Sporodiobolus, Trichosporon, Yarrowia and Zygoascus. The average yeast count in raw milk was superior to 2 log UFC.mL-1, while cheese count was superior to 3 log UFC.g-1. Lipolytic activity was present in almost 92% of the isolates, while only 14% had proteolytic activity. Twelve potentially pathogenic ascomycetic isolates were identified by the conventional yeast identification methodology, and correspond to the species Candida parapsilosis, Candida tropicalis and Pichia guilliermondii. All of them had their identities confirmed by the simplified HMA assay. None of the isolates belonging to potentially pathogenic species were resistant to the antifungal agents tested. More studies are necessary to evaluate the real significance of the isolation of these clinically relevant yeasts

Comparison of different culture media for mycological evaluation of commercial pet food

The choice of a culture media to proceed a mycological analysis of food is extremely important to guarantee the reliability of the analysis. The medium should allow an excellent recovery of fungal species present in the food at the same time that it is necessary to avoid bacterial development. Thus the real microbial ecology will be reflected in the results. The efficacy of three media for fungal isolation and quantification (potato dextrose agar, dichloran rose of bengal and chloramphenicol agar and dichloran glycerol 18% agar) was compared for analysis of 54 samples of dry commercial pet food (34 for dogs and 20 for cats). Fungi were present in 74% of samples and 23 genera were isolated and identified. Aspergillus sp. and Aspergillus niger were respectively the most frequent genera and species isolated, whatever the culture medium selected to proceed the analysis. Dichloran glycerol 18% agar was the medium that presented the best results considering both the quantity and variety of isolated fungi. Comparing the results obtained in different media, it was observed that the fungi  recovered can vary according to the selected culture medium. Eurotium was the genus that presented the biggest difference in occurrence among the media where samples were cultivated to enumeration in this study. Therefore, the utilization of specific media, selected according to the characteristics of the food to be analyzed (specially water activity) allow a better visualization of the presence of food spoilage fungi

PERSPECTIVAS SOBRE ATIVIDADES ANTIMICROBIANAS DE COMPOSTOS DERIVADOS 1,2,4-OXADIAZÓLICOS

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Suscetibilidade in vitro a antifúngicos, de amostras clínicas e ambientais de Cryptococcus neoformans isoladas no sul do Brasil

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed.Comparou-se a suscetibilidade de 69 amostras de C. neoformans isoladas de pacientes com SIDA com 13 amostras de C. neoformans isoladas do meio ambiente, frente a quatro agentes antifúngicos. Com base na metodologia preconizada pelo NCCLS (M27-A) as concentrações inibitórias mínimas (CIMs) obtidas para a anfotericina B, itraconazol e cetoconazol foram muito semelhantes nos dois grupos estudados. Todavia, frente ao fluconazol, os isolados clínicos evidenciaram menor sensibilidade do que os provenientes do meio ambiente. Alguns aspectos envolvendo a importância e dificuldades dos testes de suscetibilidade com Cryptococcus neoformans são também discutidos pelos autores

Differentiation of Candida dubliniensis from Candida albicans with the use of killer toxins

The aim of this study was to report the ability of killer toxins, previously used as biotyping techniques, as a new tool to differentiate C. albicans from C. dubliniensis. The susceptibility of C. albicans and C. dubliniensis to killer toxins ranged from 33.9 to 93.3% and from 6.67 to 93.3%, respectively.Avaliou-se a capacidade das toxinas killer, previamente utilizadas na biotipagem de C. albicans, como método para diferenciar C. albicans de C. dubliniensis. A susceptibilidade de C. albicans e C. dubliniensis às toxinas killer variou de 33,9% a 93,3% para C. albicans e de 6,67% a 93,3% para C. dubliniensis

Atividade enzimática e hemolítica de Candida dubliniensis

Candida dubliniensis is an opportunistic yeast that has been recovered from several body sites in many populations; it is most often recovered from the oral cavities of human immunodeficiency virus-infected patients. Although extensive studies on epidemiology and phylogeny of C. dubliniensis have been performed, little is known about virulence factors such as exoenzymatic and hemolytic activities. In this study we compared proteinase, hyaluronidase, chondroitin sulphatase and hemolytic activities in 18 C. dubliniensis and 30 C. albicans strains isolated from AIDS patients. C. albicans isolates produced higher amounts of proteinase than C. dubliniensis (p ; 0.05). Hemolytic activity was affected by CaCl2; when this component was absent, we did not notice any significant difference between C. albicans and C. dubliniensis hemolytic activities. On the contrary, when we added 2.5 g% CaCl2, the hemolytic activity was reduced on C. dubliniensis and stimulated on C. albicans tested strains (p ; 0,05). Constatou-se que a atividade hemolítica foi influenciada pelo CaCl2; em sua ausência não foram observadas diferenças na atividade hemolítica das duas espécies; todavia, ao se agregar 2,5% de CaCl2, a atividade hemolítica de C. dubliniensis foi reduzida enquanto a de C. albicans, estimulada (p < 0,05)

Pitiose: uma micose emergente

A pitiose é uma enfermidade piogranulomatosa do tecido subcutâneo causada pelo  Pythium insidiosum, microrganismo classificado no Reino Straminipila, Classe Oomycetes, Ordem Pythiales, Família Pythiaceae, Gênero Pythium e espécie P. insidiosum. Acomete várias espécies animais, porém a doença é mais freqüentemente observada em equinos, podendo, também, afetar os humanos. Epidemiologicamente a pitiose está intimamente relacionada com o contato dos animais e humanos com águas contaminadas pelo agente, onde produz zoosporos móveis que constituem-se na forma infectante do Pythium insidiosum. A enfermidade em eqüinos caracteriza-se principalmente pelo desenvolvimento de lesões subcutâneas ulcerativas e granulomatosas de aparência tumoral com presença de massas branco-amareladas, chamadas internacionalmente de “kunkers”. Já nas outras espécies a formação dos “kunkers” não é observada. O diagnóstico de pitiose é realizado pelos sinais clínicos, histopatologia, isolamento e identificação do agente, técnicas sorológicas como imunodifusão, ELISA e imunohistoquímica e mais recentemente por PCR. A doença destaca-se pela dificuldade no tratamento, uma vez que as drogas antifúngicas disponíveis não mostram eficiência contra o Pythium insidiosum. Atualmente a utilização de imunoterápicos constitui-se na alternativa de terapia em eqüinos, com resulatados animadores. Este trabalho tem por objetivos revisar os aspectos taxonômicos, epidemiológicos clínicos e histopatológicos da pitiose em diversas espécies. Também são abordados as técnicas diagnósticas e as perspectivas imunoterápicas

Dermatofitoses: agentes etiológicos, formas clínicas, terapêutica e novas perspectivas de tratamento

As dermatofitoses têm ocorrência mundial, sendo mais prevalentes em países de clima tropical e subtropical. Dados epidemiológicos indicam que essas micoses estão entre as infecções fúngicas de maior ocorrência. O quadro clínico mais comum de dermatofitose inclui despigmentação, placas anulares, prurido e perda de cabelo, com lesões tipicamente conhecidas como tineas, ocasionadas por fungos filamentosos dermatofíticos de três gêneros anamórficos: Microsporum, Trichophyton e Epidermophyton. O tratamento das dermatofitoses, em geral, está relacionado ao uso de antifúngicos tópicos e/ou sistêmicos, apresentando como problemática o surgimento de espécies multirresistentes. Esta revisão aborda as dermatofitoses e seus agentes etiológicos de forma aprofundada em aspectos epidemiológicos, apresentando a importância clínica do tema, com ênfase na causa, prevenção, tratamento e prognóstico dessa micose cutânea.Palavras-chave: Dermatofitoses; dermatófitos; epidemiologia; tratament