Marcos Ereno Auler

Yeasts isolated from blood and catheter in children from a Public Hospital of São Paulo, Brazil

The great majority of nosocomial fungal infections, especially fungemias, are caused by yeasts, mostly of the genus Candida. In addition, such infections may be associated with intravascular catheters. In this study, 80 yeast strains were isolated from hospitalized children, being 59 from blood cultures and 21 from vascular catheter cultures. The prevalent species in both blood and catheter was C. parapsilosis (32.2% and 48.9%, respectively), followed by C. albicans (16.9% and 28.6%, respectively). Concerning enzyme production, 78.8% of the 80 isolates presented strong proteolytic activity but 78.8% showed no phospholipase activity. We also detected two prevalent “killer” biotypes: 511 and 888. Additionally, in five patients, it was possible to observe that the yeast species, “killer” biotype and proteolytic and phospholipase activity of blood and catheter were similar. In view of this, we suggest a transmission of nosocomial yeast infection from catheter to blood.

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.

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).

Candiduria in a public hospital of São Paulo (1999-2004): characteristics of the yeast isolates

The study involved 100 yeast isolates, obtained from urine samples provided by a Public Pediatric Hospital of São Paulo, Brazil, from 1999 to 2004. The most frequent species was Candida albicans, followed by C. tropicalis, C. glabrata and C. parapsilosis. In regard to virulence, 97% of the isolates showed index 3 for proteinase and 63% index 2 for phospholipase. The most frequent killer biotypes were 511 and 888.

Dermatophytosis and immunovirological status of HIV-infected and AIDS patients from Sao Paulo city, Brazil

Over the past decades, more people became infected with human immunodeficiency virus (HIV) and developed acquired immunodeficiency syndrome (AIDS). Because of that the incidence of fungal infections rose dramatically. It happened because this virus can modify the course of fungal diseases, leading to altered clinical pictures. The aim of this study was to evaluate epidemiological and biological aspects of dermatophytosis in HIV‐positive and AIDS patients living in the city of São Paulo, Brazil. A total of 84 (44 HIV‐positive and 40 AIDS) patients were enrolled in this study. The patients were tested for dermatophyte infections, as well as for the CD4+/CD8+ and HIV viral load counts. Tinea unguium was most frequently observed in AIDS patients, whereas Tinea pedis was mostly observed in HIV‐positive patients. The most frequent dermatophyte species was Trichophyton rubrum. CD4+ counts and CD4+/CD8+ ratios were not associated with a higher risk for dermatophytosis. On the other hand, viral load higher than 100 000 copies/ml was associated with a higher frequency of dermatophytosis. The results suggest to that although dermatophytosis is common in HIV‐positive and AIDS patients, the degree of immunosuppression does not seems to correlate with increased risk of this fungal infection. In addition, high viral load as a predictive risk factor for dermatophyte infection should be subject of further evaluations.

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.

Oral colonization: a possible source for candidemia in low-weight neonates.

OBJECTIVE To check the oral colonization in neonates at high-risk and to associate these cases with candidemia. SUBJECTS AND METHODS This study was conducted in the NICU. For six months, 125 high-risk neonates were investigated for oral colonization and septicemia by yeasts. From this total, 19 neonates had yeasts on the oral mucosae and 12 neonates developed fungemia. All of the 12 neonates with fungemia were included in the amount of 19 who have presented oral colonization by yeasts. RESULTS There was a species concordance between the yeasts of the oral mucosae and the blood in 6 neonates (50%) among the 12 neonates with oral colonization and septicemia at the same time. The yeasts isolated in these 6 cases regarding the species concordance were Candida albicans (5 cases, 83.4%) and Candida parapsilosis (1 case, 16.6%). All of the cases involving an association were confirmed by PFGE. All of the strains of yeasts involved in oral colonization and also blood presented the same karyotype. A total of 66.6% of the patients with strains in agreement progressed to death. CONCLUSION The results indicate the relevance of monitoring the oral microbiota, as a possible source of fungal infection, and assisting to develop appropriate therapeutic strategy.

Trichophyton rubrum Isolated from AIDS and Human Immunodeficiency Virus-Infected Patients in São Paulo, Brazil: Antifungal Susceptibility and Extracellular Enzyme Production

Background: In order to identify intraspecific variations in Trichophyton rubrum and to correlate them to the immunological status of the host, sixty strains isolated from AIDS, HIV-positive and HIV-negative patients were compared for the production of extracellular enzymes and for their susceptibility to several antifungal drugs. Methods: The isolates were tested for their ability to secrete keratinases, proteinases, phospholipases, lipases and DNases. Likewise, we investigated their susceptibility to amphotericin B, ketoconazole, ciclopiroxolamine, griseofulvin, miconazole and tolnaftate. Results: Variations in the Minimal Inhibitory Concentration (MIC80) values were observed for all antifungals tested, but they were similarly distributed among the three clinical groups. Griseofulvin showed the most prominent differences among the three groups of isolates. Regarding enzyme secretion, all samples secreted keratinases and DNases, while none secreted phospholipases. Proteinases and lipases were secreted by some of them. Conclusions: The differences among isolates of the three groups were not statistically significant and therefore could not be ascribed to a given clinical status. Intraspecific variations similarly occurred in each group, irrespective of the immunological status of the patients.

Evaluation of infections by Candida at a university hospital of Vale do Paraíba region, São Paulo State, Brazil: species distribution, colonization, risk factors and antifungal susceptibility

The present research aimed to carry out an epidemiological study, recording the prevalence of Candida spp. causing infection, as well as the colonization, distribution of the different species in clinical specimens from different sectors of a university hospital, risk factors and their susceptibility to antifungal drugs. Over a one-year period, 100 samples of Candida from 67 patients were isolated and identified, which 74% were characterized as colonization and 26% as nosocomial infections. C. albicans was the most frequent (40%), followed by C. tropicalis (25%), C. parapsilosis (21%), C. glabrata (9%), C. rugosa (2%), C. novergensis (1%), C. krusei (1%) and C. guilliermondii (1%). Non-albicans Candida species represented 71.4% of the colonization cases and 52.1% of infection. C. albicans was the most common species found in secretions and blood, C. parapsilosis was the most isolated from venous catheter, while C. tropicalis and C. glabrata were the most frequently isolated species in probes. The hospital wards with the largest number of yeasts were the Intensive Care Units (45%). Renal failure and multiple traumas were the most frequent underlying diseases and the mainly risk factors for colonization or infection were antibiotic therapy and invasive procedures. Most of the samples showed high susceptibility to the antifungal agents studied. Epidemiological investigations of these agents in the hospital environment are very important, especially at the studied hospital, so that preventive measures may be taken against infections.