Efficacy of anidulafungin against biofilms of different Candida species in long-term trials of continuous flow cultivation.

Long-term continuous flow culture allows the investigation of dynamic biofilms under microaerophilic or aerobic conditions. We studied the biofilm formation and changes of susceptibility in 30 blood culture isolates (48 experiments) of different Candida species exposed to anidulafungin in 0.16 ml or 7.7 ml flow chambers. The flow rate (F) was adjusted to a very low rate of 1.3 ml h(-1) resulting in an exchange rate of up to 180 and 6.25 times chamber volumes per 24 hours in the small and large chambers, respectively. The results of culture at a very low flow rate were markedly different from cultures in micro well plates. Low flow rates may better mimic the in vivo situation and thus may be of higher relevance for the clinical setting. Under these conditions, a general resistance of fungal biofilms against anidulafungin cannot be confirmed. Strains of C. albicans and C. glabrata showed very uniform results whereas the C. parapsilosis group and C. lusitaniae varied from high susceptibility to resistance. Species differentiation of the C. parapsilosis group appears to be appropriate in clinical microbiological diagnostics. For the majority of the tested Candida species, anidualafungin was more effective than voriconazole. For the species C. lusitaniae and C. guilliermondii susceptibility testing should be considered prior to clinical use of echinocandin antifungals.

Is there a need for autopsies in the management of fungal disease?

The autopsy rates in Germany became low like in other European, American and Asian countries. Main reasons for this development are the lack of acceptance of autopsy in the society as well as in the medical profession, the introduction of a requirement for consent, unclear legal position, the public health system, pressure of costs and a change in the field of activity in pathology with much more diagnostics of surgical and biopsy material. The autopsy is missing with respect to the reliability of causes of death and morbidity statistics and other epidemiological studies. Published data indicate that up to 20-30% of patients who die in hospitals have important diseases/lesions that remain undetected before death but that are found at autopsy. For infectious diseases, the data are similar. Therefore, a higher incidence of invasive fungal infections was found. Some rare fungal disorders are diagnosed by autopsy. Only exact death statistics makes specific health care possible and is cost saving in a public health system in the long term. Autopsy remains an important tool for quality control in medical diagnostic and therapeutic activity. It is also essential for fundamental medical education and further training.

Candidaemia in Europe: epidemiology and resistance.

Despite the widespread use of antifungals for prophylaxis, Candida bloodstream infection (BSI) remains the most frequent life-threatening fungal disease. From an analysis of multi-institutional surveys of Candida BSIs performed in Europe, including the large prospective survey by the European Confederation of Medical Mycology (2089 episodes from seven countries), a limited role of species with decreased susceptibility to azoles in causing BSIs and a low proportion of antifungal resistance was evident. Large prospective epidemiological surveys using common databases are needed to monitor trends in incidence and changes in species distribution, to identify new at-risk patients and to evaluate the impact of the introduction into the market of new antifungal agents.

Changes in Candida albicans colonization and morphology under influence of voriconazole.

The aim was the investigation of fungal colonization and morphological alterations under the influence of voriconazole in an in vitro system. Voriconazole stopped growth and colonization of Candida albicans (wild type SC5314) on cover slips in microtiter plates dependent on drug concentration, the time of Candida growth before the input of voriconazole and oxygen concentration. The direct microscopy by fluorescence staining with the optical brightener Blancophor showed short bizarrely deformed mycelia looking swollen. The colonization on cover glass was diminished. Microcolonies or starting of biofilm formation as in the control was not observed. The metabolic activity was demonstrated by vital staining with FUN 1 resulting in red fluorescent structures in the yeast forms and mycelia in the controls. Under voriconazole influence the remaining cells only showed a green or pale yellow fluorescence. Most of the cells lost their metabolic activity.

[Early description of a pulmonary aspergillosis 1847 from Greifswald]. / Frühe Beschreibung einer pulmonalen Aspergillose 1847 aus Greifswald.

In 1847 the student of medicine Theodor Sluyter (1817-1895) from Greifswald published his thesis in Berlin including the first well-documented case of human pulmonary aspergillosis. In 1856 Rudolf Virchow (1821-1902) classified the depicted fungi as an Aspergillus species. Possibly Carl Ferdinand Eichstedt (1816-1892) carried out the autopsy. He is known by the first description of a fungus as the cause of pityriasis versicolor in 1846. Further involved scientists from Greifswald were Wilhelm Baum (1799-1883), Theodor Litzmann (1815-1890) and the botanist Johann Konrad Schauer (1813-1848). Their curricula vitae are given in further details as well the curriculum of T. Sluyter.

Anaerobic microflora under Class I and Class II composite and amalgam restorations.

OBJECTIVES: The microflora around and beneath restorations is an important factor of restoration failure. The aim of this pilot study was to determine and compare the microbial spectrum under composite and amalgam restorations with special attention to the anaerobic flora. METHOD AND MATERIALS: Ten composite and five amalgam restorations scheduled for replacement were clinically evaluated for marginal gaps, fractures, and secondary caries. After their removal and caries diagnosis, a dentin sample just below the restoration was taken under sterile conditions, stored in a prereduced transport medium for anaerobic bacteria, and immediately transferred to a laboratory for microbial diagnosis. RESULTS: The clinical parameters showing mostly moderate marginal imperfections and the ratios of aerobic to anaerobic flora were comparable for composite and amalgam restorations (11.4%:88.6% and 15.4%:84.5%, respectively). The microbial variety under composite restorations was much greater compared to amalgam, and it was similar to that of infected root canals including anaerobic gram-negative rods, such as Fusobacterium species or Porphyromonas species. Beneath amalgam, the microbial flora was similar to the one found in carious dentin and plaque, with anaerobic and facultatively anaerobic gram-positive rods dominating. Quantitatively, there were up to eight times more microorganisms under composite restorations. The number of bacterial strains correlated with the caries activity and the filling material, the number of anaerobic rods correlated highly with caries activity and localization. In a linear regression, caries activity and the filling material had statistically significant influence on the bacterial load. CONCLUSION: Although caries activity and location had the greatest influence on the microbial flora under the restorations, the kind of restoration material seemed to have an additional effect on the composition of the microflora. This pilot study indicates that inadequate composite restorations may promote the growth of cariogenic, as well as obligate anaerobic and potentially pulpopathogenic bacteria, which should be confirmed by further studies.

Influence of voriconazole and fluconazole on Candida albicans in long-time continuous flow culture.

We investigated the influence of voriconazole and fluconazole in a long term trial of continuous flow culture (cfc) up to 9 days. The effects of these azoles were different in dependence on the growth circumstances. Under anaerobic conditions a fungicidal effect of voriconazole was detectable, defined by an inhibition of 99.9%. This also applied to fluconazole for the majority of tested strains of C. albicans. Under aerobic conditions with an otherwise similar situation we found only a fungistatic reaction (inhibition of 90%). Fluorescence microscopy comparing fungal morphology in biofilms on glass surfaces in the cfc revealed a differentiation into blastospores, germ tubes, pseudomycelia and mycelia in the control trial after a cultivation of 8 days. Under anaerobic conditions with azoles only some single cells could be found, sometimes in cell detritus. The adhesion was clearly reduced. Under aerobic conditions more blastospores but no differentiated mycelia were to be seen.

The continuous flow culture as an in vitro model in experimental mycology.

We used the model of continuous flow culture (cfc) to study the growth of Candida species. This model allows special test conditions: a long generation time of 15-20 hs, controlled limitation of nitrogen sources and carbohydrates, comparison of the growth under aerobic and anaerobic conditions simultaneously. These conditions were used to study the effect of antimycotic drugs, mainly during a long time of 7 to 10 days. Germ tube formation as a virulence factor was more abundant and faster in cfc of strains with a stronger adherence to buccal epithelium cells. Co-cultivation of C. albicans and C. glabrata allowed conclusions for their colonization in vivo. A biofilm on the glass wall of the culture vessel led to mycelium formation by C. albicans. Concomitantly the growth of C. glabrata was favoured. Growth of C. albicans in the gastrointestinal flora was reduced by masses of bacteria and their multiple metabolic activities. A remarkable growth of C. albicans was only to be seen if the ecosystem was destroyed e.g. by antibacterial antibiotics. The influence of fluconazole in a long-term follow up study under anaerobic conditions showed an inhibition of C. albicans in 99.9 %. This means fungicidal efficacy.