Rosa Paulina Calvillo-Medina1,2,3,4, Magda Martínez-Neria5, Julio Mena-Portales6, Luis Barba-Escoto7, Tania Raymundo8, Juan Campos-Guillén2, George H Jones9, Juan Pablo Reyes-Grajeda3, Jorge Alberto González-Y-Merchand4, Victor Manuel Bautista-de Lucio1. 1. Departamento de Microbiología y Proteómica, Instituto de Oftalmología "Fundación Conde de Valenciana", Mexico City, México. 2. Laboratorio de Microbiología Molecular, Universidad Autónoma de Querétaro, Santiago de Querétaro, México. 3. Consorcio de Estructura de Proteínas, Instituto Nacional de Medicina Genómica, Mexico City, México. 4. Departamento de Microbiología Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, México. 5. Departamento de Oftalmología, Hospital General "Dr. Manuel Gea González", Mexico City, México. 6. Instituto de Ecología y Sistemática, La Habana, Cuba. 7. Sustainable Intensification Program México Edo. de México, International Maize and Wheat Improvement Center (CIMMYT), Mexico City, México. 8. Laboratorio de Micología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, México. 9. Department of Biology, Emory University, Atlanta, Georgia.
Abstract
BACKGROUND: In recent years, human keratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp. are phytopathogenic and recently have been recognised as a human pathogen, using biofilm formation as a virulence factor. OBJECTIVES: The aim of this study was isolation, identification (at the species level) and characterisation of a new fungal keratitis agent. PATIENTS/ METHODS: The fungus was isolated from a 67-year-old male patient with a corneal ulcer. Biofilm formation and structure were evaluated by colorimetric methods and microscopy. To identify the fungus, morphological characteristics were examined and a phylogenetic analysis was performed. RESULTS AND CONCLUSIONS: We report the identification of a fungus, a member of the genus Neoscytalidium which is associated with human keratitis. Phylogenetic analysis and morphological observations on conidiogenous cells, which occur only in arthric chains in aerial mycelium and the coelomycetous synasexual morph is absent, identified a new species, Neoscytalidium oculus sp. nov. The fungus formed biofilm at a concentration of 1 × 106 conidia/mL, during 96 hours of incubation at 37°C, and also manifested haemolysis and melanin production. This is the first report in Latin America of a new species of Neoscytalidium from a clinical isolate has been identified.
BACKGROUND: In recent years, humankeratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp. are phytopathogenic and recently have been recognised as a human pathogen, using biofilm formation as a virulence factor. OBJECTIVES: The aim of this study was isolation, identification (at the species level) and characterisation of a new fungal keratitis agent. PATIENTS/ METHODS: The fungus was isolated from a 67-year-old male patient with a corneal ulcer. Biofilm formation and structure were evaluated by colorimetric methods and microscopy. To identify the fungus, morphological characteristics were examined and a phylogenetic analysis was performed. RESULTS AND CONCLUSIONS: We report the identification of a fungus, a member of the genus Neoscytalidium which is associated with humankeratitis. Phylogenetic analysis and morphological observations on conidiogenous cells, which occur only in arthric chains in aerial mycelium and the coelomycetous synasexual morph is absent, identified a new species, Neoscytalidium oculus sp. nov. The fungus formed biofilm at a concentration of 1 × 106 conidia/mL, during 96 hours of incubation at 37°C, and also manifested haemolysis and melanin production. This is the first report in Latin America of a new species of Neoscytalidium from a clinical isolate has been identified.
Authors: Sindy V Flórez-Muñoz; Juan C Gómez-Velásquez; Natalia Loaiza-Díaz; Célia Soares; Carla Santos; Nelson Lima; Ana C Mesa-Arango Journal: Microorganisms Date: 2019-09-01