Correlation of Fusarium spp. genotyping with clinical outcomes and antifungal susceptibility of ocular isolates from South Florida (USA) and São Paulo (Brazil)

Abstract

Ocular mycoses are one of the world's most prevalent causes of ocular morbidity, principally in tropical and sub-tropical areas.In the last decades, the incidence has rised due to increased awareness and changes in risk factor profiles throughout the global population, including an increase in the use of topical steroids and antibacterial agents, as well as an increase in surgical procedures, contact lens use, ocular trauma, chronic ocular surface diseases, and immune compromised patients.Due to rapid progression of the ocular infections and potential to cause profound irreversible visual loss, failing to recognize the pathogen in a fast and specific way and to start the appropriate therapy early can cause serious damage to the infected eye.A consensus that emerged from recent genotyping studies, is that methods based on DNA sequencing are essential for the identification of the different Fusarium species in clinical microbiology laboratories, specially to differentiate Fusarium solani and Fusarium oxysporum species complexes.Besides, different fungi species respond differently to antifungals, so that some species do not have a good response to wide spectrum antifungals and necessitate specific therapy. Therefore, knowing the antifungal susceptibility of every species, can help considerably in the treatment and final clinical outcome.The aim of the present study is to analyze the genotypes of the main Fusarium species that cause keratitis in humans; determine their antifungal susceptibility profile; assess the correlation between genotypes and clinical outcomes, like visual acuity, time to cure and necessity of urgent surgical procedures; analyze the PCR's and morphologic analysis' accuracy in the diagnosis of the infecting Fusarium species; correlate the Fusarium keratitis cases in 2 high incidence regions for this fungus, South Florida (USA) and Sao Paulo (Brazil); and use the sequencing information from the ITS 1 and 2 regions of the ribosomal DNA to prove it is a reliable method to identify these pathogens to the species level. (AU)