A novel, tomographic imaging probe for rapid diagnosis of fungal keratitis

Abstract

Fungal keratitis is a leading cause of ocular morbidity and blindness in developing countries. Diagnosing fungal keratitis currently relies on a comparative evaluation of corneal biopsy or scraping using a direct microscopy and culture results. These methods not only carry the risk of developing complications due to the invasive tissue sampling but also are largely limited by diagnostic speed and accuracy, making it difficult to initiate timely appropriate antifungal therapy. Therefore, rapid and noninvasive diagnostic tools are a pressing need for improved outcomes for fungal keratitis. Taking advantage of the highly specific fungal cell targeting properties of caspofungin, we have developed a fluorescent chemical probe with high selectivity against fungal pathogens. Utilizing fluorescence imaging technology, we have demonstrated a highly specific and sensitive detection of Aspergillus in a fungal keratitis model in mice as early as 5 min post-topical application of the probe. Our results indicate that a fluorescence-mediated platform can be used as a rapid (<10 min) alternative to conventional methods for detecting Aspergillus, and potentially other fungi, in fungal infections of the cornea.

Methodologies for in vitro and in vivo evaluation of efficacy of antifungal and antibiofilm agents and surface coatings against fungal biofilms

“…Correct diagnosis of fungal infections can be problematic, however recently imaging-based tools were developed to accurately diagnose infections such as fungal keratitis. Based on the structure of caspofungin a chemical probe exhibiting high affinity to Aspergillus and possibly also other fungal pathogens was developed which could serve as a basis for development of an imaging system 307 .…”

Prevalence and genotypes of Enterocytozoon bieneusi in wildlife in Korea: a public health concern

“…Thus, wildlife animals are recognized as environmental reservoir for many human and animal infections [32, 33]. In Korea, a few studies have reported the molecular detection of E. bieneusi in livestock [34, 35] and in bats [36]; however, the infection burden of this microsporidian fungal pathogen in wildlife is largely unknown. Therefore, in the present study, the prevalence and genotypes of this parasite in wild animal populations in Korea were determined.…”

Experimental Models for Fungal Keratitis: An Overview of Principles and Protocols

“…At 24 h post-intrastromal injection of Aspergillus conidia, animals were anesthetized, and the probe was applied topically to the corneal ulcer. Within 5 min of the application, a fluorescent signal was detectable and quantifiable with an in vivo confocal microscopy; the signal disappeared at 60 min of application [47]. Thus, this method allows for the prospective assessment of fungal burden in the same animal, similar to the fluorescent reporter strain approach.…”

“…Then, a 33G Hamilton syringe is inserted into the tunnel to deliver a 1-2 µL inoculum directly into the underlying stroma. Regardless of fungal species, 10 5 total conidia is commonly used inoculum, although this can vary by a log-fold either way [1,32,[47][48][49][50][51][52].…”