Most Candida spp. infections are associated with biofilm formation on host surfaces. Cells within these communities display a phenotype resistant to antimicrobials and host defenses, so biofilm-associated infections are difficult to treat, representing a source of reinfections. The present study evaluated the effect of eugenol on the adherence properties and biofilm formation capacity of Candida dubliniensis and Candida tropicalis isolated from the oral cavity of HIV-infected patients. All isolates were able to form biofilms on different substrate surfaces. Eugenol showed inhibitory activity against planktonic and sessile cells of Candida spp. No metabolic activity in biofilm was detected after 24 h of treatment. Scanning electron microscopy demonstrated that eugenol drastically reduced the number of sessile cells on denture material surfaces. Most Candida species showed hydrophobic behavior and a significant difference in cell surface hydrophobicity was observed after exposure of planktonic cells to eugenol for 1 h. Eugenol also caused a significant reduction in adhesion of most Candida spp. to HEp-2 cells and to polystyrene. These findings corroborate the effectiveness of eugenol against Candida species other than C. albicans, reinforcing its potential as an antifungal applied to limit both the growth of planktonic cells and biofilm formation on different surfaces.

Introduction: Host colonization by Candida species is an important predisposing factor to candidiasis, which seems to be more frequent in human immunodeficiency virus (HIV)-infected patients. Knowledge about the distribution, antifungal susceptibility, and virulence of oral Candida isolates is important for effective management of candidiasis. Methodology: Oral rinses were collected from 242 HIV-infected patients without clinical evidence of candidiasis seen at the AIDS referral center in Londrina, Brazil. Species were identified by standard phenotypic and molecular methods, and characterized in vitro according to antifungal susceptibility, cell surface hydrophobicity, biofilm formation, and enzyme activities. Results: Oral Candida colonization was detected in 50.4% of patients and combined use of antiretroviral therapy and protease inhibitor had a protective effect against colonization. Candida albicans (75.2%) was the most prevalent species. A high proportion of Candida spp. (39.9%) showed decreased susceptibility to fluconazole. Five isolates were resistant to nystatin. Protease and phospholipase activities were detected in 100% and 36.8% of isolates, respectively. Most isolates displayed a hydrophobic property that was associated with biofilm formation ability. Conclusions: A significant number of oral Candida species exhibiting decreased susceptibility to fluconazole were isolated from colonized HIV-infected individuals. Furthermore, all isolates expressed potential virulence attributes in vitro. Given the high incidence and severity of fungal infections in HIV-infected individuals, the results of this study reinforce the importance of antifungal susceptibility testing, which contributes to therapeutic strategies and highlights the need for continuous surveillance of Candida colonization in this population.

The aim of this study was to isolate yeasts from the faeces of urban bats inhabiting the city of Londrina, Paraná, Brazil and to determine their potential virulence attributes. Seven (12.3%) of 57 bats screened in this study showed yeasts in their faeces. Five species of the genus Candida were isolated: C. guilliermondii, C. krusei, C. lusitaniae, C. parapsilosis, and C. pelliculosa. No phospholipase activity was detected in the egg yolk plate assay; however, all isolates demonstrated protease secretion in skim milk agar. Yeasts isolated from bats produced biofilm on the surface of polystyrene plates and all were classified as intermediate biofilm producers. Minimal inhibitory concentration (MIC) values for fluconazole in the yeasts varied according to the species. Only one isolate (M34 - C. lusitaniae) was considered susceptible dose-dependent to fluconazole. The yeasts were injected intravenously into Swiss mice, and at 15 days post-infection, the animals were killed and portions of their kidneys cultured on Sabouraud dextrose agar medium. All tissues analysed showed positive cultures of Candida spp. This is the first study evaluating the presence of fungi in the faeces of bats in an urban region, where the yeast species found were shown to be potentially pathogenic. As bats are commonly found in cities, these findings indicate the need for continuous surveillance concerning environmental contamination by their excreta.

Enterococcus faecium, especially those showing multidrug resistance, has emerged as a significant cause of healthcare-associated infections worldwide. However, relatively little is known about the virulence and pathogenesis of this species. The aim of this study was to determine the occurrence of four putative virulence determinants of E. faecium and to correlate them with phenotypic traits. Using forty E. faecium vanA-type isolates from hospitalized patients and their environmental vicinity, we determined the following: the antimicrobial susceptibility profile, occurrence of the genes cylA, efaA, esp, and gelE, hemolytic and gelatinase activities, capacity to form biofilm and in vitro adhesion to epithelial cells. All isolates were shown to be resistant to vancomycin and teicoplanin, as well as to two or more other antimicrobials. All isolates harbored at least one putative virulence marker, and the prevalence was as follows: esp, 87.5%; efaA, 82.5%; gelE, 70%; and cylA, 65%. The presence of 4 genes was observed in 32.5% isolates. The presence of the efaA was associated with the presence of esp, regardless of the source of the isolates. A positive association with the presence of cylA and hemolytic activity in the sheep blood agar assay was observed. No association was found for gelE and gelatinase production in the agar plate assay, for efaA and LLC-MK2 cell adhesion, and for esp and biofilm formation on polystyrene surface. These results show the presence of putative virulence genes in multiple antimicrobial resistant E. faecium isolates from different sources in a hospital setting.

We described for the first time an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST1284 carrying a plasmid-mediated bla in Brazil. The bla was harbored by an integron that also carried aacA4 and bla. Multiple virulence factors were also detected.