Candidemia in the intensive care unit: Miles to go before we sleep*:

Successful Release of Voriconazole and Flavonoids from MAPLE Deposited Bioactive Surfaces

We explored the potential of biomimetic thin films fabricated by means of matrix-assisted pulsed laser evaporation (MAPLE) for releasing combinations of active substances represented by flavonoids (quercetin dihydrate and resveratrol) and antifungal compounds (amphotericin B and voriconazole) embedded in a polyvinylpyrrolidone biopolymer; the antifungal activity of the film components was evaluated using in vitro microbiological assays. Thin films were deposited using a pulsed KrF* excimer laser source which were structurally characterized using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). High-quality thin films with chemical structures similar to dropcast ones were created using an optimum laser fluence of ~80 mJ/cm2. Bioactive substances were included within the polymer thin films using the MAPLE technique. The results of the in vitro microbiology assay, which utilized a modified disk diffusion approach and were performed using two fungal strains (Candida albicans American Type Culture Collection (ATCC) 90028 and Candida parapsilosis American Type Culture Collection (ATCC) 22019), revealed that voriconazole was released in an active form from the polyvinylpyrrolidone matrix. The results of this study show that the MAPLE-deposited bioactive thin films have a promising potential for use in designing combination devices, such as drug delivery devices, and medical device surfaces with antifungal activity.

Sequence-identification of Candida species isolated from candidemia

Background:

Candida species are the most prevalent cause of invasive fungal infections such as candidemia. Candidemia is a lethal fungal infection among immunocompromised patients worldwide. Main pathogen is Candida albicans but a global shift in epidemiology toward non-albicans species have reported. Species identification is imperative for good management of candidemia as a fatal infection. The aim of the study is to identify Candida spp. obtained from candidemia and determination of mortality rate among this population.

Materials and Methods:

The study was performed during February 2014 to March 2015 in Tehran, Iran. Two-hundred and four blood cultures were evaluated for fungal bloodstream infection. Identification of isolates was carried out using phenotypic tests and polymerase chain reaction sequencing technique.

Results:

Twenty-two out of 204 patients (10.8%) had candidemia. Candida parapsilosis was the most prevalent species (45.4%), followed by C. albicans (31.8%) and Candida glabrata (22.7%). Male to female sex ratio was 8/14.

Conclusions:

The emergence of resistant strains of Candida species should be considered by physicians to decrease the mortality of this fatal fungal infection by appropriate treatment.

Null mutants of Candida albicans for cell-wall-related genes form fragile biofilms that display an almost identical extracellular matrix proteome

By two-dimensional gel electrophoresis (2-DE) and mass spectrometry, we have characterized the polypeptide species present in extracts obtained by 60% ethanol treatment of whole mature (48 h) biofilms formed by a reference strain (CAI4-URA3) and four Candida albicans null mutants for cell-wall-related genes (ALG5, CSA1, MNN9 and PGA10) Null mutants form fragile biofilms that appeared partially split and weakly attached to the substratum contrary to those produced by the reference strain. An almost identical, electrophoretic profile consisting of about 276 spots was visualized in all extracts examined. Proteomic analysis led to the identification of 131 polypeptides, corresponding to 86 different protein species, being the rest isoforms-83 displayed negative hydropathic indexes and 82 lack signal peptide. The majority of proteins appeared at pI between 4 and 6, and molecular mass between 10 and 94 kDa. The proteins identified belonged to the following Gene Ontology categories: 21.9% unknown molecular function, 16.2% oxidoreductase activity, 13.3% hydrolase activity and 41.8% distributed between other different GO categories. Strong defects in biofilm formation appreciated in the cell-wall mutant strains could be attributed to defects in aggregation due to abnormal cell wall formation rather than to differences in the biofilm extracellular matrix composition.

Frequency of decreased susceptibility and resistance to echinocandins among fluconazole-resistant bloodstream isolates of Candida glabrata

The echinocandin class of antifungal agents is considered to be the first-line treatment of bloodstream infections (BSI) due to Candida glabrata. Recent reports of BSI due to strains of C. glabrata resistant to both fluconazole and the echinocandins are of concern and prompted us to review the experience of two large surveillance programs, the SENTRY Antimicrobial Surveillance Program for the years 2006 through 2010 and the Centers for Disease Control and Prevention population-based surveillance conducted in 2008 to 2010. The in vitro susceptibilities of 1,669 BSI isolates of C. glabrata to fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin were determined by CLSI broth microdilution methods. Fluconazole MICs of ≥64 μg/ml were considered resistant. Strains for which anidulafungin and caspofungin MICs were ≥0.5 μg/ml and for which micafungin MICs were ≥0.25 μg/ml were considered resistant. A total of 162 isolates (9.7%) were resistant to fluconazole, of which 98.8% were nonsusceptible to voriconazole (MIC > 0.5 μg/ml) and 9.3%, 9.3%, and 8.0% were resistant to anidulafungin, caspofungin, and micafungin, respectively. There were 18 fluconazole-resistant isolates that were resistant to one or more of the echinocandins (11.1% of all fluconazole-resistant isolates), all of which contained an acquired mutation in fks1 or fks2. By comparison, there were no echinocandin-resistant strains detected among 110 fluconazole-resistant isolates of C. glabrata tested in 2001 to 2004. These data document the broad emergence of coresistance over time to both azoles and echinocandins in clinical isolates of C. glabrata.

Antifungal susceptibility profiles of Candida isolates from a prospective survey of invasive fungal infections in Italian intensive care units

The antifungal susceptibility pattern of 302 Candida isolates collected during an Italian survey on invasive fungal infections in an intensive care setting was investigated. The results were correlated with some epidemiological data and compared with the antifungal profiles obtained in a previous survey. No resistance to echinocandins was detected. The overall resistance levels to fluconazole, posaconazole and voriconazole were 12.6, 6.0 and 7.1 %, respectively. Candida tropicalis and Candida parapsilosis accounted for more than half of all the fluconazole resistant isolates. Reduced susceptibility to fluconazole is not uncommon among isolates (12.3 %) and appears to be increasing, particularly among C. parapsilosis isolates, which showed an increase in resistant isolates from 2 % in the 1990s to 25.8 % in the present study. Routine antifungal susceptibility testing of this species is therefore recommended.