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Penicillamine is a chelator that has been used in Wilson's disease, cystinuria, rheumatoid arthritis and heavy metal intoxication. We report a case of a 31-year-old man presented with skin atrophy, purpura and milia on the hips and shoulders after taking penicillamine for 1.5 years. According to literature review, this type of penicillamine-associated cutaneous adverse effect belongs to degenerative dermopathy, which mostly occurs on bony prominences and points of pressure in patients with Wilson's disease or cystinuria. Withdrawal or reduction of drug dose can improve the features of degenerative dermopathy.

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM Objectives The black yeast Exophiala dermatitidis is an opportunistic pathogen that causes phaeohyphomycosis in both immunocompetent individuals and immunosuppressed patients, resulting in localized cutaneous and subcutaneous infections to more severe systemic forms such as neurotropic infections. Besides, E. dermatitidis was frequently found as a colonizer of pulmonary of cystic fibrosis patients, which appears to be associated with more advanced disease. Infections of E. dermatitidis are often chronic and recalcitrant. Previously, we have demonstrated that pyrvinium pamoate (PP) exerted antifungal activity alone (MIC 2 μg/ml) and favorable synergy with azoles against E. dermatitidis in vitro, which was confirmed in vivo via Galleria mellonella model. Further investigation revealed pyrvinium resulted in significant growth restriction of E. dermatitidis, reduction of biofilm formation, and significantly (P Methods The knockout strain named △Exfr was constituted via polyethyleneglycol (PEG)-mediated transformation of protoplasts. A gene replacement cassette was generated as described. E. dermatitidis wild-type strain ATCC34100 DNA was used for molecular cloning. The pan7-1 plasmid vector, which contained the genetic markers hygromycin B phosphotransferase, was applied as a selection marker provider. DNA manipulation was performed according to standard laboratory procedures. The 5′ and 3′ flanking regions of fumaric reductase analog coding gene Exfr (Genbank geneID 20312383) were amplified using the primers ExfruF, ExfruR, and ExfrdF, ExfrdR, respectively. The selection maker Hph was amplified from pan7-1 by using primers hphF and hphR. These three fragments are subsequently fused via PCR with primers ExfuF and ExfuR. The protoplasts of wild-type strain ATCC34100 were prepared as described. Further, the fused gene fragment and PEG was mixed with protoplast to complete transformation, and the transformants were transferred to SDA solid culture base (containing a final concentration of 50 μg/ml hygromycin). DNA extracted from the transformants that could grow stably on HPH medium was sent for sequencing to verify that the target gene had been introduced into the location. The growth, morphology, and in vitro susceptibility of ATCC34100 and △Exfr were further investigated. Results There was no significant difference in the colony or conidial morphology. However, the growth rate of △Exfr was slightly slower than that of the wild-type strain. In addition, the MICs of pyrvinium pamoate (PP) and voriconazole against △Exfr were 2-fold higher (16 ug/ml and 0.5ug/ml, respectively), compared with that of the wild-type strain. Conclusion The preliminary results suggested that fumaric reductase analog may play an important role in drug sensitivity of E. dermatitidis, especially the sensitivity to PP and voriconazole. In addition, △Exfr is currently the only E. dermatitidis strain that was successfully knocked out by protoplast procedure, which provides reference for subsequent researches on E. dermatitidis gene knockout.

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM Objectives Exophiala dermatitidis is an emerging opportunistic pathogen among the ever-increasing numbers of immunocompromised hosts. Understanding its transmission mechanism, pathogenicity, and potential azole-resistant mechanism is important for better understanding of this fatal pathogen and benefits future diagnosis, and treatment. By using a PCR-based fragment fusion approach, we applied phosphotransferase (HPH) resistance gene which amplified from pAN7-1 as a selective gene for generating replacement cassettes. Combined with electroporation transformation and screening on selection medium containing 50 μg/ml HMB, we obtained the gene knockout strain Δ GAL4, a novel GAL4-like transcriptional factor (XP_009154426.1) encoding gene (GeneID:20 306 783) accurately deleted. Methods Growth curve determination: Take 200 μL of 2 × 10⁴ CFU/ml bacterial suspension and 200 μL liquid sabourand medium in EP tubes. Shaking at 200 rpm 37°C for 0 h, 1 h, 2 h, 3 h, 4 h, 8 h, 12 h, 16 h, 18 h, 24 h, 30 h, 36 h, 48 h. Then add 200 μL cultured bacterial suspension to a 96-well plate and repeat three times. Meanwhile set up blank medium control wells. By using an enzyme marker to measure the absorbance at 504 nm, analyzing with SPSS, and then graphing with GraphPad software. Morphological observations: Activated strains on Sabourand microcultures and incubated at 37 °C for 3d. Observe morphology by using fluorescent microscopy to compare the different strains of wild and knockout strains, and using lactic acid cotton phenol blue/fluorescent dye filming observe the morphology of conidia. E-test drug sensitivity method: Spread fresh bacterial suspension of ΔGAL4 and ATCC34100 containing 1 × 10⁶CFU/ml spores on RPMI 1640 agar plates with sterile cotton swabs, and place drug sensitivity test strips [itraconazole (Itraconazole Liofilchem, ICZ 92148), posaconazole (Posaconazole Liofilchem (PCZ 92152), voriconazole (Mérieux, VRC 532800)] in the center plate, after sealing with a parafilm, incubating in 37°C for 36-48 h, and read the values at the tangent of the drug susceptibility strip and the antibacterial circle. Results The results revealed that the ΔGAL4 showed almost no difference in growth and morphology compared with wild strain, but its sensitivity to azoles was altered. We applied E-test to evaluate the MIC changes of azoles. The MIC of itraconazole, voriconazole, and posaconazole against ΔGAL4 was 0.5 μg/ml, 0.125 μg/ml, and 0.25 μg/ml; against ATCC34100 was 2 μg/ml, 0.19 μg/ml, and 0.38 μg/ml, respectively. △GAL4 MIC suggests that ∆GAL4 showed more sensitivity to azoles compared to its wild-type strain. Conclusion The present results suggested that a novel GAL4-like transcriptional factor may play an important role in azole sensitivity of E. dermatitidis, which may be through modulating efflux pumps or Cyp51A. Further investigation of this GAL4 related modulating pathway is needed.

Depending on their chemical structure, insecticides enter the insect body either through the cuticle or by ingestion (mode of entry [MoE]), and, naturally, harm or even kill insects through different mechanisms (modes of action). In parallel, they trigger a systemic detoxification response, especially by activation of detoxification gene expression. We monitored the acute genetic alterations of known xenobiotic response target genes against five different insecticides with two most common MoEs (contact toxicity and stomach toxicity), found that: 1. only a few genes were detected responding to acute exposure to insecticides (LD

Insects have evolved a powerful detoxification system to protect themselves against environmental and anthropogenic xenobiotics including pesticides and nanoparticles. The resulting tolerance to insecticides is an immense problem in agriculture. In this study, we summarize advances in our understanding of insect xenobiotic responses: the detoxification strategies and the regulation mechanisms against xenobiotics including nanoparticles, the problem of response specificity and the potential usefulness of this study field for an elaborate pest management. In particular, we highlight that versatility of the detoxification system relies on the relatively unspecific recognition of a broad range of potential toxic substances that trigger either of various canonical xenobiotic responses signaling pathways, including CncC/Keap1, HR96, AHR/ARNT, GPCR, and MAPK/CREB. However, it has emerged that the actual response to an inducer may nevertheless be specific. There are two nonexclusive possibilities that may explain response specificity: (1) differential cross-talk between the known pathways and (2) additional, yet unidentified regulators and pathways of detoxification. Hence, a deeper and broader understanding of the regulation mechanisms of xenobiotic response in insects in the future might facilitate the development and application of highly efficient and environmentally friendly pest control methods, allowing us to face the challenge of the world population growth.

Mucormycosis is an aggressive and high-mortality opportunistic fungal infection, especially in immunocompromised patients. Conventional antifungals or surgery showed a limited effect on this disease. The antimicrobial photodynamic therapy (aPDT) has been proven to be a promising therapeutic choice against multiple pathogenic fungi. We evaluated the effect of aPDT by using methylene blue (MB) combined with a light emitting diode (LED) on the viability of Rhizopus oryzae, as well as the antifungal susceptibility after aPDT treatment in vitro. A total of six strains were included in this study; MB (8, 16, and 32 μg/ml) was chosen for the photosensitizer, and a light source of LED (635 ± 10 nm, 12 J/cm2) device was used to active it. aPDT with MB (32 μg/ml) and LED was highly effective in cell growth inhibition and exhibited colony-forming unit reductions of up to 4.3log10. The minimal inhibitory concentration ranges of itraconazole, posaconazole, and amphotericin B decreased from > 32 μg/ml to 4–8 μg/ml, 8–16 μg/ml to 0.5–2 μg/ml, and 2–4 μg/ml to 0.25–0.5 μg/ml, respectively, after pre-treatment with MB (8 μg/ml) and LED. In conclusion, aPDT with MB and LED was a promising therapeutic option against R. oryzae infections alone or combined with antifungal agents. However, further investigation is needed to determine the potential for clinic therapy and to elucidate the underlying mechanism.

In vitro and in vivo interactions of minocycline and azoles, including itraconazole, voriconazole, and posaconazole, against filamentous pathogenic fungi were investigated. A total of 56 clinical isolates were studied in vitro via broth microdilution checkerboard technique, including 20 strains of Aspergillus fumigatus, 7 strains of Aspergillus flavus, 16 strains of Exophiala dermatitidis, 10 strains of Fusarium solani, and 3 strain s of Fusarium oxysporum. The results revealed that minocycline did not exhibit any significant antifungal activity against any of the tested strains. However, favorable synergy of minocycline with itraconazole, voriconazole, or posaconazole was observed against 34 (61%), 28 (50%), and 38 (68%) isolates, respectively, including azole-resistant A. fumigatus and Fusarium spp. with inherently high MICs of azoles. Synergistic combinations resulted in 4-fold to 16-fold reduction of effective MICs of minocycline and azoles. No antagonism was observed. In vivo effects of minocycline-azole combinations were evaluated by survival assay in a Galleria mellonella model infected with E. dermatitidis strain BMU00034; F. solani strain FS9; and A. fumigatus strains AF293, AFR1, and AFR2. Minocycline acted synergistically with azoles and significantly increased larvae survival in all isolates (P

Insects are a great menace in agriculture and vectors of human diseases. Hence, controlling insect populations is an important issue worldwide. A common strategy to control insects is the application of insecticides. However, insecticides entail three major problems. First, insecticides are chemicals that stress ecosystems and may even be harmful to humans. Second, insecticides are often unspecific and also eradicate beneficial insect species like the honeybee. Third, insects are able to develop resistance to insecticides. Therefore, the efficient generation of new potent insecticides and their intelligent delivery are the major tasks in agriculture. In addition, acceptance or refusal in society is a major issue that has to be considered in the application of a pest management strategy. In this paper, we unify two issues: 1) we illustrate that our molecular knowledge of the chitin synthesis and organization pathways may offer new opportunities to design novel insecticides that are environmentally harmless at the same time being specific to a pest species; and 2) we advocate that the fruit fly Drosophila melanogaster may serve as an excellent model of insect to study the effects of insecticides at the genetic, molecular and histology level in order to better understand their mode of action and to optimize their impact. Especially, chitin synthesis and organization proteins and enzymes are excellently dissected in the fruit fly, providing a rich source for new insecticide targets. Thus, D. melanogaster offers a cheap, efficient and fast assay system to address agricultural questions, as has been demonstrated to be the case in bio-medical research areas.

Candida auris is an emerging pathogen that has caused numerous severe infections in recent years, and has therefore become a global concern for public health agencies. Most conventional antifungal agents, especially fluconazole, have shown limited effects on this pathogen. New methods to restrict this pathogen are in urgent demand. Antimicrobial photodynamic therapy (aPDT) has been shown to be a promising technique against multiple pathogenic fungi. This study sought to determine the in vitro effect of aPDT using methylene blue (MB) combined with light-emitting diode (LED) on the viability of planktonic cells and biofilms of five clinical strains of C. auris. MB (8, 16 and 32 μg/ml) was applied as the photosensitizer, and a LED (635 nm, 12 and 24 J/cm2) device was used as light source to activate the photosensitizer. The results showed that there was no growth of tested C. auris strains following aPDT on planktonic cultures. In addition, aPDT exhibited colony-forming unit reduction of up to 7.20 log10 against C. auris biofilms. These data demonstrate that in vitro aPDT with MB and LED offers promising potential for the treatment of C. auris infections.

Background Microascus cirrosus, the teleomorph of Scopulariopsis spp., is a saprobic species with a worldwide distribution and rarely causes human infection. In the present paper, we present the first case of primary cutaneous M. cirrosus infection in a Chinese female. Case presentation A 17-year-old female presented with tender ulceration on her left ankle for three months. Histology revealed multiple branching, septate hyphae and moniliform fungal elements in the dermis. Tissue culture grew M. cirrosus, the teleomorph of Scopulariopsis spp., characterized by intercalary and ballooned, chlamydospore-like structures, annellidic and ampulliform conidiogenous cells along with truncated, bullet-shaped, smooth conidia and globose perithecial ascomata with cylindrical necks. Further molecular sequencing confirmed the identification. A diagnosis of primary cutaneous infection due to M. cirrosus was made. Treatment with itraconazole 200 mg per day for 10 weeks achieved significant improvement of the skin lesions. Conclusions This case of uncommon mycotic cutaneous infection highlights the importance of mycological examination that help to recognize rare pathogenic fungi.

In vitro interactions of tacrolimus, a calcineurin inhibitor, and azoles, including itraconazole, voriconazole, and posaconazole, against planktonic cells and biofilms of Exophiala dermatitidis were assessed via a broth microdilution checkerboard technique. A total of 16 clinical isolates were studied. The results revealed favorable synergistic inhibitory activity between tacrolimus and itraconazole, voriconazole, or posaconazole against 68.8%, 87.5%, and 100% of tested strains of planktonic E. dermatitidis , respectively.However, limited synergism was observed against biofilms of E. dermatitidis . No antagonism was observed in all combinations.

Aspergillus biofilms were prepared from Aspergillus fumigatus , Aspergillus flavus , and Aspergillus terreus via a 96-well plate-based method, and the combined antifungal activity of tacrolimus with azoles or amphotericin B against Aspergillus biofilms was investigated via a broth microdilution checkerboard technique system. Our results suggest that combinations of tacrolimus with voriconazole or amphotericin B have synergistic inhibitory activity against Aspergillus biofilms. However, combinations of tacrolimus with itraconazole or posaconazole exhibit no synergistic or antagonistic effects.

In vitro interactions of AT406, a novel IAP antagonist, and azoles including itraconazole, voriconazole, and fluconazole against planktonic cells and biofilms of Candida albicans and Exophiala dermatitidis were assessed via broth microdilution checkerboard technique. AT406 alone exhibited limited antifungal activity. However, synergistic effect between AT406 and fluconazole was observed against both planktonic cells and biofilms of C. albicans, including one fluconazole-resistant strain. Moreover, synergism was also demonstrated between AT406 and itraconazole against both planktonic cells and biofilms of E. dermatitidis. No interaction was observed between AT406 and voriconazole. No antagonism was observed in all combinations.

Farnesylation, which is catalyzed by farnesyltransferase, promotes membrane association of the modified protein and protein-protein interactions, and plays an important role in a number of physiological processes of pathogenic fungi, including stress response, environmental adaption and virulence. Lonafarnib is an orally bioavailable nonpeptide tricyclic farnesyltransferase inhibitor with excellent pharmacokinetic and safety profile. In the present study, we investigated the in vitro activities of lonafarnib alone or combined with azoles, including itraconazole, voriconazole, and posaconazole, against 22 strains of Aspergillus spp. and 18 strains of Exophiala dermatitidis via broth microdilution checkerboard technique. Lonafarnib alone was inactive against all isolates tested. However, synergistic effects between lonafarnib and itraconazole were observed in 86% Aspergillus strains and 94% E. dermatitidis strains. In addition, lonafarnib/posaconazole combination also exhibited synergism against 59% of Aspergillus strains and 100% E. dermatitidis strains. However, synergistic effects of lonafarnib/voriconazole were only observed in 32% Aspergillus strains and 28% E. dermatitidis strains. The effective working ranges of lonafarnib were 2-4 μg/ml and 1-4 μg/ml against Aspergillus isolates and E. dermatitidis isolates, respectively. No antagonism was observed in all combinations. This study demonstrated that lonafarnib could enhance the in vitro antifungal activity of itraconazole, posaconazole and voriconazole against Aspergillus spp. and E. dermatitidis, suggesting that azoles, especially itraconazole and posaconazole, combined with farnesyltransferase inhibitor might provide a potential strategy to the management of Aspergillus and Exophiala infections. However, further studies are warranted to elucidate the underlying mechanism and to investigate the potential of reliable and safe application in clinical practice.

Scedosporium and Lomentospora species are the second most frequent colonizing, allergenic, or invasive fungal pathogens in patients with cystic fibrosis, and are responsible for infections varying from cutaneous and subcutaneous tissue infections caused by traumatic inoculation to severe systemic diseases in immunocompromised patients. The clinical relevance of fungal airway colonization for individual patients harboring Scedosporium and Lomentospora species is still an underestimated issue. The high resistance of Scedosporium and Lomentospora species to antifungal drugs has highlighted the need for alternative treatment modalities, and antimicrobial photodynamic therapy may be one such alternative. In this study, methylene blue was applied as a photosensitizing agent to 6 type strains of Scedosporium and Lomentospora species, and we irradiated the strains using a light-emitting diode (635 ± 10 nm, 12 J/cm2). We evaluated the effects of photodynamic therapy on strain growth and on the in vitro susceptibility of the strains to itraconazole, voriconazole, posaconazole, and amphotericin B. A colony-forming unit reduction of up to 5.2 log10 was achieved. Minimal inhibitory concentration ranges also decreased significantly with photoinactivation. Photodynamic therapy improved both the inactivation rates and the antifungal susceptibility profile of all fungal isolates tested.

Infections of Exophiala spp. and Fusarium spp. are often chronic and recalcitrant. Systemic disseminations, which mostly occur in immunocompromised patients, are often refractory to available antifungal therapies. The conserved target of rapamycin (TOR) orchestrates cell growth and proliferation in response to nutrients and growth factors, which are important for pathogenicity and virulence. INK128 is a second-generation ATP-competitive TOR inhibitor, which binds the TOR catalytic domain and selectively inhibits TOR. In the present study, we investigated the in vitro activities of INK128 alone and the interactions of INK128 with conventional antifungal drugs including itraconazole, voriconazole, posaconazole, and amphotericin B against 18 strains of Exophiala spp. and 10 strains of Fusarium spp. via broth microdilution checkerboard technique system adapted from Clinical and Laboratory Standards Institute broth microdilution method M38-A2. INK128 alone was inactive against all isolates tested. However, favorable synergistic effects between INK128 and voriconazole were observed in 61% Exophiala strains and 60% Fusarium strains, despite Fusarium strains exhibited high MIC values (4–8 μg/ml) against voriconazole. In addition, synergistic effects of INK128/itraconazole were shown in 33% Exophiala strains and 30% Fusarium strains, while synergy of INK128/posaconazole were observed in 28% Exophiala strains and 30% Fusarium strains. The effective working ranges of INK128 were 0.125–2 μg/ml and 1–4 μg/ml against Exophiala isolates and Fusarium isolates, respectively. No synergistic effect was observed when INK128 was combined with amphotericin B. No antagonism was observed in all combinations. In conclusion, INK128 could enhance the in vitro antifungal activity of voriconazole, itraconazole and posaconazole against Exophiala spp. and Fusarium spp., suggesting that azoles, especially voriconazole, combined with TOR kinase inhibitor might provide a potential strategy to the treatment of Exophiala and Fusarium infections. However, further investigations are warranted to elucidate the underlying mechanism and to determine possible reliable and safe application in clinical practice.

In vitro interactions of INK128, a target of rapamycin (TOR) kinase inhibitor, and antifungals, including itraconazole, voriconazole, posaconazole, amphotericin B, and caspofungin, against Aspergillus spp. were assessed with the broth microdilution checkerboard technique. Our results suggested synergistic effects between INK128 and all azoles tested, against multiple Aspergillus fumigatus and Aspergillus flavus isolates. However, no synergistic effects were observed when INK128 was combined with amphotericin B or caspofungin. No antagonism was observed for any combination.

Infections of Fusarium spp. and Exophiala spp. are often chronic, recalcitrant, resulting in significant morbidity, causing discomfort, disfigurement, social isolation. Systemic disseminations happen in compromised patients, which are often refractory to available antifungal therapies and thereby lead to death. The antimicrobial photodynamic therapy (aPDT) has been demonstrated to effectively inactivate multiple pathogenic fungi and is considered as a promising alternative treatment for mycoses. In the present study, we applied methylene blue (8, 16, and 32 μg/ml) as a photosensitizing agent and light emitting diode (635 ± 10 nm, 12 and 24 J/cm(2)), and evaluated the effects of photodynamic inactivation on five strains of Fusarium spp. and five strains of Exophiala spp., as well as photodynamic effects on in vitro susceptibility to itraconazole, voriconazole, posaconazole and amphotericin B, both planktonic and biofilm forms. Photodynamic therapy was efficient in reducing the growth of all strains tested, exhibiting colony forming unit-reductions of up to 6.4 log10 and 5.6 log10 against planktonic cultures and biofilms, respectively. However, biofilms were less sensitive since the irradiation time was twice longer than that of planktonic cultures. Notably, the photodynamic effects against Fusarium strains with high minimal inhibitory concentration (MIC) values of ≥16, 4-8, 4-8, and 2-4 μg/ml for itraconazole, voriconazole, posaconazole and amphotericin B, respectively, were comparable or even superior to Exophiala spp., despite Exophiala spp. showed relatively better antifungal susceptibility profile. MIC ranges against planktonic cells of both species were up to 64 times lower after aPDT treatment. Biofilms of both species showed high sessile MIC50 (SMIC50) and SMIC80 of ≥16 μg/ml for all azoles tested and variable susceptibilities to amphotericin B, with SMIC ranging between 1 and 16 μg/ml. Biofilms subjected to aPDT exhibited a distinct reduction in SMIC50 and SMIC80 compared to untreated groups for both species, except SMIC80 of itraconazole against Fusarium biofilms. In conclusion, in vitro photodynamic therapy was efficient in inactivation of Fusarium spp. and Exophiala spp., both planktonic cultures and biofilms. In addition, the combination of aPDT and antifungal drugs represents an attractive alternative to the current antifungal strategies. However, further investigations are warranted for the reliable and safe application in clinical practice.

Background Photoallergic contact dermatitis (PACD) is of importance in a proportion of photodermatoses and can be evaluated through photopatch testing (PPT). Objectives The objectives of this study were to evaluate the results of PPT and investigate the prevalence of PACD reactions to different photoallergens in Chinese patients at the Department of Dermatology of Huashan Hospital Fudan University during a 7-year period. Methods A retrospective PPT study was conducted. During the 7 years, 4957 patients attending for investigation of suspected photodermatoses were tested according to the European consensus methodology with up to 14 allergens prepared according to Chinese National Standards. The reactions were scored using the International Contact Dermatitis Research Group visual scoring system. Results A total of 3472 PACD reactions in 2454 subjects (49.5%) were recorded. The most common agents were chlorpromazine (44.3%), followed by para-aminobenzoic acid (14.7%), thimerosal (8.9%), and sulfanilamide (6.9%). Allergic contact dermatitis reactions comprised 409 reactions in 399 subjects (8%). Photoinhibition and photoaugmentation of allergic contact dermatitis compromised 3810 reactions in 2412 subjects and 11 reactions in 11 subjects, respectively. Irritant reactions (1928 reactions) were seen in 1140 subjects. Conclusions The most predominant photoallergens in our region were chlorpromazine, para-aminobenzoic acid, thimerosal, and sulfanilamide, which likely reflected the particular exposures of this Chinese population.

In vitro interactions of givinostat, a hydroxamate-derived histone deacetylase inhibitor, and antifungals including itraconazole, voriconazole, posaconazole, amphotericin B and caspofungin against Aspergillus spp. were assessed via broth microdilution checkerboard technique system. A total of 30 isolates of Aspergillus spp., including 20 strains of A. fumigatus and 10 strains of A. flavus were studied. The results revealed favorable synergistic effects between givinostat and posaconazole (83.3%) against Aspergillus isolates. Limited synergism was observed when givinostat was combined with itraconazole or voriconazole. No interaction was observed between givinostat and amphotericin B or caspofungin. No antagonism was observed in all combinations.

Background Exophiala dermatitidis causes a variety of illnesses in humans which are always refractory to available treatment modalities. Hsp90 governs crucial stress responses, cell wall repair mechanisms and antifungal resistance in pathogenic fungi. Thus, targeting Hsp90 with specific inhibitors holds considerable promise as combination strategy. Objectives To investigate the antifungal effect of 17-AAG alone or combined with azoles against E. dermatitidis. Methods In vitro interactions of 17-AAG, a Hsp90 inhibitor, and azoles including itraconazole, voriconazole and posaconazole against E. dermatitidis were evaluated via broth microdilution chequerboard technique, adapted from the CLSI M38-A2 method. A total of 18 clinical strains were studied. Candida parapsilosis (ATCC22019) was included to ensure quality control. Results and conclusions 17-AAG alone exhibited minimal antifungal activity against all tested isolates. However, synergistic effects between 17-AAG and posaconazole, itraconazole or voriconazole were observed against 15 (83.3%), 12 (66.7%) and 1 (5.6%) isolates of E. dermatitidis, respectively. The effective working ranges of 17-AAG in synergistic combinations were mostly within 2-8 μg/mL. No antagonism was observed. In conclusion, harnessing fungal Hsp90 with 17-AAG might prove a potential antifungal regimen for E. dermatitidis infections. However, due to the host toxicity of 17-AAG, more efforts are needed to develop fungal specific Hsp90 inhibitors.