The emerging "super fungus" Candida auris has become an important threat to human health due to its pandrug resistance and high lethality. Therefore, the development of novel antimicrobial strategy is essential. Antimicrobial photodynamic therapy (aPDT) has excellent performance in clinical applications. However, the relevant study on antifungal activity and the mechanism involved against C. auris remains scarce. Herein, a recyclable and biodegradable polylactic acid-hypocrellin A (PLA-HA) nanofibrous membrane is newly developed. In vitro PLA-HA-aPDT could significantly reduce the survival rate of C. auris plankton and its biofilms, and the fungicidal effect of the membrane is still significant after four repeated uses. Simultaneously, PLA-HA exhibits good biocompatibility and low hemolysis. In vivo experiments show that PLA-HA-aPDT can promote C. auris-infected wound healing, reduce inflammatory response, and without obvious toxic side-effects. Further results reveal that PLA-HA-aPDT could increase endogenous reactive oxygen species (ROS) levels, leading to mitochondrial dysfunction, release of cytochrome C, activation of metacaspase, and nuclear fragmentation, thereby triggering apoptosis of C. auris. Compared with HA, PLA-HA shows stronger controllability and reusability, which can greatly improve the utilization efficiency of HA alone. Taken together, the efficacy, safety and antifungal activity make PLA-HA-aPDT a highly promising antifungal candidate for skin or mucous membrane C. auris infection.

Skin and soft tissue infections (SSTIs) are very common in dermatology and the use of antimicrobial formulations are important in treating these diseases. With the increasing of drug-resistant strains, researchers need to find ways to enhance the effectiveness and/or reduce the drug resistance. Clioquinol was one of antiseptics that can inactivate microbes. It was lack of data of antimicrobial activity; meanwhile it was infrequently used in infection. In order to research the antimicrobial spectrum and activity of topical 3% clioquinol cream among common pathogenic microorganisms compared with other common topical pharmaceuticals, we used modified agar diffusion assay to judge drug susceptibility and compared with broth microdilution assay. Thirty strains of pathogenic fungi belonging to 14 species and 5 strains of pathogenic bacterium belonging to 4 species from clinic or standard strains were enrolled into the experiment. The inhibition zone around 3% clioquinol cream for all experiment isolates was observed. It could inhibit the growth of most fungal species with different strength, but the antibacterial activity was weak. For Candida tropicalis, Candida guilliermondii, Aspergillus terreus, Fusarium solani and Trichoderma harzianum, the inhibition zone was biggest among all the tested drugs. The antifungal activity for Dermatophytes and Candida albicans was moderate. Two assays had a degree of consistency. Based on results above, we identified the antifungal spectrum of 3% clioquinol cream was broad. The antimicrobial strength of 3% clioquinol cream depended on the species but it can act on most of the species.

Infections caused by multidrug-resistant fungi pose a devastating threat to human health worldwide, making new antifungal strategies urgently desired. Antimicrobial photodynamic therapy (aPDT) has gained increasing attention due to its potential in fighting against fungal infection. However, the preparation of highly efficient and water-soluble photosensitizers (PSs) for this purpose remains a challenge. Herein, we present a new strategy to prepare powerful PSs for efficient aPDT by introducing a porous cage compound, which could facilitate the transportation of O₂ and reactive oxygen species (ROS). Specifically, the natural PS hypocrellin A (HA) was attached to a novel organic cage compound (covalent organic polyhedra 1 tied, COP1T) with polyethylene glycol (PEG) chains to improve its water solubility. It was found that the resulting COP1T-HA exhibited in vitro antifungal efficiency several folds higher compared to the free HA in fighting against four types of multidrug-resistant fungal planktonic cells and biofilms, including the "super fungus" Candida auris. Interestingly, the red-shift of COP1T-HA adsorption led to the realization of phototheranostic aPDT for cage-modified HA or derivatives. Additionally, COP1T-HA exhibited good biocompatibility, excellent disinfection capacity and wound healing efficiency without obvious toxic effects in vivo of rat model. With further development and optimization, COP1T-HA has great potential to become a new class of antifungal agent to fight against drug-resistant pathogens.