RAPD differentiation of Malassezia spp. from cattle, dogs and humans.

The molecular characterization of Malassezia spp. isolates from animals and humans has not been thoroughly studied. We have analysed the DNA profile by random amplified polymorphic DNA (RAPD)-PCR to compare the genetic diversity between isolates from the external ears of cattle, dogs and humans. The analysis of electrophoretic profiles on 8% polyacrylamide gel and their phenograms showed genetic heterogeneity between RAPD profiles of Malassezia furfur and Malassezia slooffiae isolates from humans and cattle and between Malassezia pachydermatis isolates from dogs and cattle. Intra-species variations in DNA pattern of Malassezia isolates and the presence of specific genetic types in cattle, dogs or humans were observed. A review of genetic heterogeneity of these yeast in veterinary and human medicine studies is given considering a possible transmission animal to human or human to animal. Additional studies must clarify the differences between the RAPD band patterns observed in this and other studies, which would facilitate monitoring of Malassezia spp. carriage in domestic animals and in humans.

Diversity and antifungal susceptibility of yeasts from tropical freshwater environments in Southeastern Brazil.

Yeast communities were isolated from water and sediment samples of two unpolluted natural lakes, located inside Rio Doce State Park, and two rivers located outside of this Park in Southeastern Brazil. A total of 134 yeast isolates were obtained and identified as belonging to 36 species. The numbers of fecal coliforms and yeast species were higher in rivers than in lakes. The genus Candida had the highest number of species with the presence of opportunistic pathogens such as Candida krusei, C. tropicalis, C. guilliermondii and C. parapsilosis. Yeasts able to grow at 37 degrees C were tested in relation to their susceptibility to common used antifungal drugs. Yeast isolates (13%) were susceptible to ketoconazole, 79% to fluconazole, 31% to terbinafine and 78% of the strains were susceptible to amphotericin B. Seven isolates from different Candida species were resistant to all antifungals tested. The high number of fecal coliforms found in these aquatic environments and the presence of resistant yeast strains to common used antifungal drugs suggest that these environments can pose potential health risks for people utilizing the contaminated waters.

Identification and antimicrobial susceptibility of micro-organisms recovered from cutaneous lesions of human American tegumentary leishmaniasis in Minas Gerais, Brazil.

An evaluation of the microbiota present in cutaneous ulcers from 31 patients with a clinical and parasitological diagnosis of American tegumentary leishmaniasis (ATL) was carried out by the standard filter paper disc technique, including antimicrobial susceptibility of the bacterial isolates. Microbial examination indicated that 21 patients (67.7%) were contaminated with one to four bacteria and some of them also with yeast. A total of 142 micro-organisms were isolated. Staphylococcus aureus was the most frequently recovered bacterium (95.2% of positive patients) and was found to produce type B (70% of the staphylococcal isolates) and type C (50%) enterotoxins as well as toxic shock syndrome toxin (60%). Proteus mirabilis (33.3% of the positive patients), Streptococcus pyogenes (19.0 %), H(2)S-negative Proteus species (19.0%), Klebsiella oxytoca (14.3%), Enterobacter species (9.5%), Peptostreptococcus species (9.5%), Pseudomonas species (4.8%), Prevotella bivia (4.8%), Escherichia coli (4.8%), Streptococcus agalactiae (4.8%), Bacteroides fragilis (4.8%), Candida albicans (9.5%) and Candida tropicalis (4.8%) were also isolated. Surprisingly, Staph. aureus isolates were susceptible to almost all tested drugs, although some of them were resistant to penicillin (69%) and ampicillin + sulbactam (68%). Concerning obligate anaerobes, all the Gram-negative isolates (25% of the total) were resistant to metronidazole. The results of the present study show that microbial secondary contaminants, particularly Staph. aureus, should be considered in the diagnosis and treatment of ATL lesions.