Fusarium keratitis in South India: causative agents, their antifungal susceptibilities and a rapid identification method for the Fusarium solani species complex

Abstract

Seventy Fusarium isolates derived from human keratomycosis were identified based on partial sequences of the β-tubulin (β-TUB) and translation elongation factor 1α (EF-1α) genes. Most of the isolates were confirmed as members of the F. solani species complex (75.71%), followed by the F. dimerum species complex (8.57%), the F. fujikuroi species complex (8.57%), the F. oxysporum species complex (4.29%) and the F. incarnatum-equiseti species complex (2.86%). A combined phylogenetic tree was estimated including all the 70 isolates. Isolates belonging to different species complexes formed separate clades. In this study, we also report the first isolation of F. napiforme from human keratomycosis. A new method based on a specific EcoRI restriction site in the EF-1α gene was developed for the rapid identification of F. solani. In vitro antifungal susceptibilities of the isolates to seven antifungals were determined by broth microdilution method. Terbinafine, natamycin and amphotericin B proved to be the most effective drugs, followed by voriconazole. The minimal inhibitory concentrations of clotrimazole, econazole and itraconazole were generally high (≥64 μg ml(-1) ). The interactions between the two most effective antifungals (natamycin and terbinafine) were determined by checkerboard microdilution method. Synergism (71.8%) or no interaction (28.2%) was revealed between the two compounds.

In vitro susceptibility of filamentous fungi from mycotic keratitis to azole drugs

“…In the present study, the common aetiological agents of corneal ulcers were identified as filamentous fungi rather than bacteria. Similar results were obtained by Bharathi et al [6], Manikandan et al [24] and Homa et al [15] in South India. Leck et al [22] also reported similar results from South, North and East India.…”

Fusarium napiforme systemic infection: case report with molecular characterization and antifungal susceptibility tests

“…In immunocompetent persons, Fusarium usually causes localized infections (Bourgeois et al 2010; De Pinho et al 2012; Calcaterra et al 2013; Homa et al 2013). Conversely, immunocompromised hosts, mainly those with acute onco-hematological diseases or after allogeneic hematopoietic stem cell transplant, have high risk of invasive life-threatening diseases.…”

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Molds of the Fusarium Genus

“…However, according to in vitro testing, antifungal susceptibility profiles have been shown to vary between Fusarium species (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). Correct identification to the species or species complex level may thus be crucial for patient treatment, although no in vitro-in vivo correlations have been demonstrated, and treatment is dependent on the type of infection (27).…”