Rapid and Visual RPA-Cas12a Fluorescence Assay for Accurate Detection of Dermatophytes in Cats and Dogs.

Dermatophytosis, an infectious disease caused by several fungi, can affect the hair, nails, and/or superficial layers of the skin and is of global significance. The most common dermatophytes in cats and dogs are Microsporum canis and Trichophyton mentagrophytes. Wood's lamp examination, microscopic identification, and fungal culture are the conventional clinical diagnostic methods, while PCR (Polymerase Chain Reaction) and qPCR (Quantitative PCR) are playing an increasingly important role in the identification of dermatophytes. However, none of these methods could be applied to point-of-care testing (POCT). The recent development of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) based diagnostic platform promises a rapid, accurate, and portable diagnostic tool. In this paper, we present a Cas12a-fluorescence assay to detect and differentiate the main dermatophytes in clinical samples with high specificity and sensitivity. The Cas12a-based assay was performed with a combination of recombinase polymerase amplification (RPA). The results could be directly visualized by naked eyes under blue light, and all tested samples were consistent with fungal culture and sequencing results. Compared with traditional methods, the RPA-Cas12a-fluorescence assay requires less time (about 30 min) and less complicated equipment, and the visual changes can be clearly observed with naked eyes, which is suitable for on-site clinical diagnosis.

Cutaneous manifestations of a 21st century worldwide fungal epidemic possibly complicating the COVID-19 pandemic to jointly menace mankind.

In view of the new viral COVID-19 pandemic, the fungal Candida auris epidemic still in progress worldwide highlights non-Candida albicans candidal infections. We describe an immunocompetent woman with a cutaneous manifestation of Candida parasilopsis fungemia, a prominent eschar, which proved to be the nidus for the candidemia. We stress the value of selectively removing eschars. C. parasilopsis and C. auris are increasingly important causes of sepsis and wound infections. We emphasize that commercially available biochemical-based tests may misidentify C. auris as C. parapsilosis, and stress the added danger of C. auris to critically ill-hospitalized COVID-19 patients. Any health care facility with evidence of infection or colonization with C. auris requires very close monitoring, since this fungus is a nosocomial threat comparable to SARS-CoV-2 in its mortality and fomite adhesiveness! Both organisms have the potential to be transmitted as nosocomial pathogens; health care workers need to follow strict CDC guidelines. During this COVID-19 pandemic, every health care facility should closely monitor for the possible deadly combination of the SARS-CoV-2 and C. auris. The identification of C. auris necessitates use of sophisticated technology not readily available to make this essential diagnosis since C. auris is multi-drug resistant and isolation precautions would become paramount.