Biofilm formation on intrauterine devices in patients with recurrent vulvovaginal candidiasis.

A biofilm is a complex community of surface-associated cells enclosed in a polymer matrix. They attach to solid surfaces and their formation can be affected by growth conditions and co-infection with other pathogens. The presence of biofilm may protect the microorganisms from host defenses, as well as significantly reduce their susceptibility to antifungal agents. Pathogenic microbes can form biofilms on the inert surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices (IUDs). The present study was carried out to analyze the presence of biofilm on the surface of intrauterine devices in patients with recurrent vulvovaginal candidiasis, and to determine the susceptibility profile of the isolated yeasts to amphotericin B and fluconazole. Candida albicans was recovered from the IUDs and it was found to be susceptible to the antifungal agents when tested under planktonic growing conditions. These findings indicate the presence of the biofilm on the surface of the IUD as an important risk factor for recurrent vulvovaginal candidiasis.

Antifungal susceptibility of bloodstream yeasts isolated at a public children's hospital in Brazil: comparison of the Etest and the AFST-EUCAST microdilution method.

This study compared the minimum inhibitory concentration (MIC) results from the proposed standard methods of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST) with the commercial system Etest(R) in the evaluation of susceptibility to flucytosine, fluconazole, itraconazole, voriconazole, and amphotericin B of 136 Candida spp. isolated from the blood of hospitalized children. The results presented a greater agreement among Etest(R) MICs +/-2 log2 dilutions of AFST-EUCAST for fluconazole (98.1% and 96.3%) and voriconazole (100% and 100%) for Candida albicans and Candida parapsilosis. For Candida glabrata, the agreement was greater only for fluconazole (81.8%) and voriconazole (100%). For amphotericin B, the agreement between the methods was low for all species. The agreement percentage among the Etest(R) and AFST-EUCAST susceptibility profiles was high according to the MIC breakpoints recommended by the M27-A2 protocol for the majority of the yeasts, except for fluconazole and itraconazole against Candida tropicalis and for itraconazole against C. glabrata and Candida krusei. According to both methodologies, a great number of Candida spp. isolates showed an in vitro susceptibility to all evaluated antifungal agents. Overall, both procedures can be reliable techniques for susceptibility tests of yeasts, but the assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response are of great importance.

Comparative analysis of Etest and broth microdilution method (AFST-EUCAST) for trends in antifungal drug susceptibility testing of Brazilian Cryptococcus neoformans isolates.

A prospective study was performed to evaluate the correlation between the proposed standard of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST) (document 7.1) and the commercial system Etest for determining the MICs of flucytosine, amphotericin B, fluconazole, itraconazole and voriconazole for a collection of 100 clinical and environmental isolates of Cryptococcus neoformans. The agreements among Etest MICs within +/-2 log2 dilutions of AFST-EUCAST standard MICs were greater for flucytosine, fluconazole and voriconazole (76, 78 and 88 %, respectively) than for amphotericin B (5 %), the lowest agreement, and itraconazole (67 %). Overall, the correlation coefficients were statistically significant (P<0.05), and it is suggested that the Etest and AFST-EUCAST method are reliable alternatives and present good correlation for all drugs evaluated except amphotericin B. However, the observed differences related to MICs for susceptible, susceptible dose dependent and resistant strains between the methods suggest that it will be necessary to carry out further studies, including assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response.

Genotyping by RAPD-PCR analyses of Malassezia furfur strains from pityriasis versicolor and seborrhoeic dermatitis patients.

Malassezia furfur is lypophilic yeast commonly associate with dermatological disorders. In the present work, we described the isolation of 47 M. furfur strains from three groups of patients: pityriasis versicolor (21 isolates), seborrhoeic dermatitis (15 isolates) and seborrhoeic dermatitis of the HIV positive patients (11 isolates). To investigate the identity of the strains at molecular level, DNA genomic of M. furfur strains were prepared and used to RAPD-PCR analyses. RAPD assay were carried out using two decamer primers and bands pattern generated were analyzed by an Unweighted Pair-Group Method (UPGMA). Dendrogram established a distinct differentiation between M. furfur isolates from pityriasis versicolor and seborrhoeic dermatitis patients with or without AIDS. We concluded that RAPD typing presented a high discriminatory power between strains studied in this work and can be applied in epidemiological investigation of skin disease causing by M. furfur.

Nosocomial infection in newborns by Pichia anomala in a Brazilian intensive care unit.

Disseminated candidiasis is the most common nosocomial fungal infection, and Candida albicans has been reported to account for 50% to more than 70% of cases of invasive candidiasis. However, recent reports have also suggested the emergence of infections caused by non-albicans species. In addition, less-common pathogenic yeasts (Malassezia, Trichosporon, Rhodotorula, Debaryomyces and Pichia) have recently been reported, with increased frequency, as causes of nosocomial infections with high mortality. This article describes two cases of fungemia caused by Pichia anomala in newborns that occurred in an intensive care unit (ICU), in November 2004 at the Instituto da Criança (Pediatric Institute) of the Hospital das Clínicas of the School of Medicine, São Paulo University, Brazil. The principal factors related to virulence (proteinase and phospholipase) and the susceptibility of the isolated strains to antifungal agents were also evaluated, and the biotype of each strain was determined through the use of an epidemiological marker (killer biotype).