Rapid differentiation of Candida albicans from non-C. albicans directly in a variety of clinical specimens using fluorescent in situ hybridisation

Glucose effect on Candida albicans biofilm during tissue invasion

OBJECTIVE

To evaluate, in vitro, the effect of two glucose concentrations (0.1 mM and 1.0 mM, simulating glucose concentration in saliva of healthy and diabetic individuals) on Candida albicans biofilm grown on epithelial monolayer.

MATERIAL AND METHODS

C. albicans was inoculated on epithelial monolayers supplemented with 0.1 mM, 1.0 mM or no glucose. Control groups without C. albicans were also evaluated. Tissue response was assessed through the production of Interleukin-1α, Interleukin-8, Interleukin-6, Interleukin-10 and tumor necrosis factor-α. The complex of monolayer and biofilms were evaluated by quantitative reverse transcription polymerase chain reaction for expression of E-cadherin (CDH1), Caspase-3 (CASP3), β-defensin-1 (DEFB-1) and β-defensin-3 (DEFB-3). The biofilm architecture was visualized by confocal laser scanning microscopy.

RESULTS

The production of Interleukin-1α and Interleukin-8 were increased in the presence of C. albicans (p < 0.05). Glucose did not interfere in the release of any cytokine evaluated. C. albicans downregulated transcripts for CDH1 (p < 0.05). Glucose did not induce a significant change in CDH1, CASP3, DEFB-1 and DEFB-3 messenger RNA expression. The biofilms were more structured in the presence of glucose, but no difference in the diffusion of hyphae through the epithelial cells were observed.

CONCLUSIONS

The data suggest that glucose concentration does not affect the behavior of C. albicans during tissue invasion and other mechanisms must be related to the greater susceptibility of diabetic individuals to candidiasis.

Rapid and Selective Detection of Pathogenic Bacteria in Bloodstream Infections with Aptamer-Based Recognition

Sepsis and bacteremia are life-threatening clinical syndromes associated with significant patient morbidity and mortality. Rapid and sensitive detection of pathogenic bacteria is the key to improve patient survival rates. Herein, we have rationally constructed a simple aptamer-based capture platform to shorten the time needed for confirmation of bacterial bloodstream infection in clinical blood samples. This capture platform is made of a mesoporous TiO2-coated magnetic nanoparticle and is modified with target aptamer. It features excellent bacterial enrichment efficiency of about 80% even at low bacterial concentrations (10-2000 CFU mL(-1)). More importantly, the bacteria can be enriched within 2 h, and the time for bacterial identification is effectively shortened in comparison to the "gold standard" in clinical diagnosis of bloodstream infection. The aptamer-based capture platform may pave a way for the detection of biomarkers and find potential applications in disease diagnosis.

[Invasive fungal disease: conventional or molecular mycological diagnosis?]

Diagnosis of invasive mycoses is a difficult challenge due to the limitations and low sensitivity of traditional microbiology methods which lead to diagnostic and therapeutic delays. The aim of this review is to summarise the state of the art of the molecular diagnosis of invasive fungal disease and to clarify its current role in the clinical practice. Conventional microbiological methods could be complemented with molecular methods in the rapid and definitive identification of fungal isolates. Biomarkers (β-glucan, galactomannan) are very useful in immunocompromised patients and have been included as probable invasive mycoses by the EORTC/MSG. Nucleic acid detection is currently used as a complementary tool for diagnosis. However, PCR can be very useful in mould invasive mycoses. Finally, the combined detection using biomarkers can improve the diagnosis. However, their applicability in the microbiology laboratory is not so easy and further studies are required for the appropriate evaluation of its clinical usefulness.

Treatment and prophylaxis of invasive candidiasis with anidulafungin, caspofungin and micafungin and its impact on use and costs: review of the literature

Invasive fungal infections are on the rise. Echinocandins are a relatively new class of antifungal drugs that act by inhibition of a key enzyme necessary for integrity of the fungal cell wall. Currently there are three available agents: caspofungin, micafungin and anidulafungin. While the individual echinocandin antifungals have a different spectrum of licensed indications, basically all of them are available for the treatment of candidemia and invasive candidiasis. Antifungal treatment modalities basically include in therapy for suspected or proven infection and prophylaxis. All three drugs are comparatively expensive. Therefore a systematic review of the literature was performed to investigate the following aspects: * General aspects of cost-effectiveness in the treatment of invasive fungal infections * Cost-effectiveness of the treatment with the above-mentioned antifungals * Cost-effectiveness in two settings: therapy and prophylaxis - Early initiation of antifungal therapy, adjustment after availability of microbiological results, duration of therapy, success and occurrence of severe complications (e.g. renal failure) are the most important cost drivers in antifungal therapy. - Considering the specific antifungals, for caspofungin the best evidence for cost-effectiveness is found in treatment of invasive candidiasis and in empiric therapy of suspected infections. Favourable economic data are available for micafungin as a cost-effective alternative to LAmB for prophylaxis in patients with hematopoietic stem cell transplantation (HSCT). For anidulafungin, cost-effectiveness was demostrated in a pharmacoeconomic model. Net savings - yet not significant - were observed in a retrospective chart review of 234 patients. Generally, however, most analyses are still based on pharmacoeconomic modelling rather than direct analysis of trial data or real-life clinical populations. - As an overall conclusion, using caspofungin, micafungin, or anidulafungin is not more expensive than using other established therapies. Micafungin has proven to be cost-effective in prophylaxis if the local fungal epidemiology indicates a high level of resistance to fluconazole. Switch strategies involving early initiation of broadly active therapy with switch to cheaper alternatives according to microbiology results and clinical status and early initiation of an appropriate therapy have been proven to be cost-efficient independent of the antifungal agent.