Over the last decade, we have observed a high frequency of Aspergillus rhinosinusitis in french medical centers. The epidemiological data, clinical presentations, radiology, mycology and histology results of 173 consecutive patients with paranasal sinus fungus balls who were admitted from 1989 to 2002 have been reviewed. The most common symptoms included purulent nasal discharges and nasal obstructions, with the maxillary sinus being the most common site of infection (152 cases, 87.8%). Computed tomography scans (CT scan) were performed in 92% (159/173) of the cases and heterogeneous opacities were observed in 132 patients (83%). Histology examinations were performed in all cases and proved positive in 162 patients. Fungi were recovered, mainly Aspergillus fumigatus, from samples of 50 patients, while specimens from the remaining 123 patients were negative. Since no specific clinical sign could be found, a diagnosis of fungus ball is frequently made after a long term symptomatic period. CT scan findings of metallic or calcified densities within an opacified sinus cavity are highly suggestive of a fungus ball, but mycological and histological studies are essential to confirm the diagnosis. Treatment consisted of functional endonasal sinus surgery and was successful in 172 out of 173 cases.

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This study demonstrated that caspofungin used at MIC was not sufficient to reduce C. albicans biofilms, but it suggested an activity on C. parapsilosis biofilms depending on their maturation age. This study also indicated that caspofungin used at 2 mg/L could be a good candidate in the prevention of candidiasis associated with silicone medical devices. Our results also suggested that fluconazole resistance of yeasts did not affect caspofungin activity.

Legionella pneumophila, the causative agent of Legionnaires' disease, is ubiquitously found in aquatic environments, associated with free living amoebae. Trophozoite forms of the genus Acanthamoeba have been shown to support the intracellular growth of Legionella while it has been proposed that cyst forms are related to survival in harsh environments. This underlines that amoebae are of primary importance in Legionella spreading. In this study, we followed the survival of L. pneumophila Lens over 6 months in a poor medium, with or without Acanthamoeba castellanii. The results demonstrated that L. pneumophila Lens could survive for at least 6 months in association with A. castellanii and that cultivable bacteria are to be found within expelled vesicles rather than within cysts. Our findings suggest that vesicles might be further studied in order to elucidate their production and their role in the environmental spreading of Legionella.

Free-living amoebae are protists frequently found in water and soils. They feed on other microorganisms, mainly bacteria, and digest them through phagocytosis. It is accepted that these amoebae play an important role in the microbial ecology of these environments. There is a renewed interest for the free-living amoebae since the discovery of pathogenic bacteria that can resist phagocytosis and of giant viruses, underlying that amoebae might play a role in the evolution of other microorganisms, including several human pathogens. Recent advances, using molecular methods, allow to bring together new information about free-living amoebae. This review aims to provide a comprehensive overview of the newly gathered insights into (1) the free-living amoeba diversity, assessed with molecular tools, (2) the gene functions described to decipher the biology of the amoebae and (3) their interactions with other microorganisms in the environment.

These data suggest that caspofungin (2 mg/L) and micafungin (5 mg/L) could represent good candidates for the reduction or control of fungal biofilms associated with silicone medical devices, as part of an antifungal lock. They were able to induce a significant and persistent reduction in the yeast metabolic activity of intermediate and mature biofilms, 12 h and 5 days old, respectively, when used as catheter lock solutions.

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ABSTRACTFree-living amoebae are protozoa found in soil and water. Among them, some are pathogenic and many have been described as potential reservoirs of pathogenic bacteria. Their cell cycle is divided into at least two forms, the trophozoite and the cyst, and the differentiation process is named encystment. As cysts are more resistant to disinfection treatments than trophozoites, many studies focused on encystment, but until recently, little was known about cellular, biochemical, and molecular modifications operating during this process. Important signals and signaling pathways at play during encystment, as well as cell responses at the molecular level, have been described. This review summarizes our knowledge and focuses on new findings.