Aspergillus fumigatus and aspergillosis: From basics to clinics.

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

Need of non-operative caries treatment in 16-year-olds from Northern Norway.

AIM: To assess the prevalence of proximal enamel lesions, the need for non-operative caries treatment and the quality of dental restorations in 869 students aged 16 years from Northern Norway. METHODS: All first year upper secondary school students in Tromsø and Balsfjord municipalities were invited to participate in an oral- and general health project (Fit Futures). The attendance rate was 90%, and all subjects born in 1994 (449 males and 420 females) were included in the present study. Dental caries was registered according to a 5-graded scale (1-2 = enamel lesions; 3-5 = dentinal lesions). Scores from 1 to 4 were used to register the quality of restorations (1 = good; 2 = acceptable; 3 = poor; 4 = unacceptable). RESULTS: Only 6% of the 16-year-olds were completely caries-free. There were 84% of the participants with proximal enamel lesions. A majority of them had either previously restored teeth (35%) or both restored teeth and untreated dentinal caries lesions (34%). When using the D-value of the DMFS-index as a diagnostic criterion, 39% of the participants were in need of restorative treatment. When proximal enamel lesions were included in the diagnosis, the number of participants in need of restorative and/or non-operative caries treatment was 85%. Over 1/3 of the participants presented with at least one restoration below an acceptable quality level. CONCLUSIONS: Dental caries is still a major health problem affecting the total teenage population. A non-operative treatment strategy should be considered relevant in order to reduce the need for restorative treatment.

Module-detection approaches for the integration of multilevel omics data highlight the comprehensive response of Aspergillus fumigatus to caspofungin.

BACKGROUND: Omics data provide deep insights into overall biological processes of organisms. However, integration of data from different molecular levels such as transcriptomics and proteomics, still remains challenging. Analyzing lists of differentially abundant molecules from diverse molecular levels often results in a small overlap mainly due to different regulatory mechanisms, temporal scales, and/or inherent properties of measurement methods. Module-detecting algorithms identifying sets of closely related proteins from protein-protein interaction networks (PPINs) are promising approaches for a better data integration. RESULTS: Here, we made use of transcriptome, proteome and secretome data from the human pathogenic fungus Aspergillus fumigatus challenged with the antifungal drug caspofungin. Caspofungin targets the fungal cell wall which leads to a compensatory stress response. We analyzed the omics data using two different approaches: First, we applied a simple, classical approach by comparing lists of differentially expressed genes (DEGs), differentially synthesized proteins (DSyPs) and differentially secreted proteins (DSePs); second, we used a recently published module-detecting approach, ModuleDiscoverer, to identify regulatory modules from PPINs in conjunction with the experimental data. Our results demonstrate that regulatory modules show a notably higher overlap between the different molecular levels and time points than the classical approach. The additional structural information provided by regulatory modules allows for topological analyses. As a result, we detected a significant association of omics data with distinct biological processes such as regulation of kinase activity, transport mechanisms or amino acid metabolism. We also found a previously unreported increased production of the secondary metabolite fumagillin by A. fumigatus upon exposure to caspofungin. Furthermore, a topology-based analysis of potential key factors contributing to drug-caused side effects identified the highly conserved protein polyubiquitin as a central regulator. Interestingly, polyubiquitin UbiD neither belonged to the groups of DEGs, DSyPs nor DSePs but most likely strongly influenced their levels. CONCLUSION: Module-detecting approaches support the effective integration of multilevel omics data and provide a deep insight into complex biological relationships connecting these levels. They facilitate the identification of potential key players in the organism's stress response which cannot be detected by commonly used approaches comparing lists of differentially abundant molecules.

Dental erosion: Prevalence and severity among 16-year-old adolescents in Troms, Norway.

AIM: To study the prevalence, distribution and severity of dental erosion among 16-year-old adolescents in the Troms region of Norway. MATERIALS AND METHODS: Study design: The participants were recruited through the Tromsø-study ("Fit Futures"), and 392 16-year-olds were examined for dental erosion using clinical intraoral photographs. Three calibrated clinicians used the Visual Erosion Dental Examination (VEDE) system to register and grade the dental erosive wear. RESULTS: More than one third (38%) of the participants showed dental erosion on at least one tooth surface, 18% were limited to the enamel, while 20% of the adolescents showed erosive wear extending into the dentine. The occlusal surfaces of the lower first molars, and the palatal surfaces of the maxillary incisors were the most often and most severely affected. Of the participants showing dental erosion, 93% exhibited "cuppings" on the molars, with 48% limited to the enamel and 52% extending into the dentine. The highest prevalence of "cuppings" (73%) was found on the first lower molars, especially the mesiobuccal cusp of the teeth. The prevalence and severity of dental erosion was found to be higher in male than in female participants (p < 0.0001). CONCLUSION: The results from this study indicate a high prevalence and severity of dental erosion among adolescents in Troms and stress the importance of information, early and effective diagnostics and implementation of prevention strategies.

Candida glabrata persistence in mice does not depend on host immunosuppression and is unaffected by fungal amino acid auxotrophy.

Candida glabrata has emerged as an important fungal pathogen of humans, causing life-threatening infections in immunocompromised patients. In contrast, mice do not develop disease upon systemic challenge, even with high infection doses. In this study we show that leukopenia, but not treatment with corticosteroids, leads to fungal burdens that are transiently increased over those in immunocompetent mice. However, even immunocompetent mice were not capable of clearing infections within 4 weeks. Tissue damage and immune responses to microabscesses were mild as monitored by clinical parameters, including blood enzyme levels, histology, myeloperoxidase, and cytokine levels. Furthermore, we investigated the suitability of amino acid auxotrophic C. glabrata strains for in vitro and in vivo studies of fitness and/or virulence. Histidine, leucine, or tryptophan auxotrophy, as well as a combination of these auxotrophies, did not influence in vitro growth in rich medium. The survival of all auxotrophic strains in immunocompetent mice was similar to that of the parental wild-type strain during the first week of infection and was only mildly reduced 4 weeks after infection, suggesting that C. glabrata is capable of utilizing a broad range of host-derived nutrients during infection. These data suggest that C. glabrata histidine, leucine, or tryptophan auxotrophic strains are suitable for the generation of knockout mutants for in vivo studies. Notably, our work indicates that C. glabrata has successfully developed immune evasion strategies enabling it to survive, disseminate, and persist within mammalian hosts.