Publications by authors named "Tania Raymundo"

4 Publications

  • Page 1 of 1

Purpureocillium roseum sp. nov. A new ocular pathogen for humans and mice resistant to antifungals.

Mycoses 2021 Feb 1;64(2):162-173. Epub 2020 Nov 1.

Departamento de Microbiología y Proteómica Ocular, Instituto de Oftalmología "Fundación de Asistencia Privada Conde de Valenciana", Mexico City, Mexico.

Background: Infectious keratitis is the main cause of preventable blindness worldwide, with about 1.5-2.0 million new cases occurring per year. This inflammatory response may be due to infections caused by bacteria, fungi, viruses or parasites. Fungal keratitis is a poorly studied health problem.

Objectives: This study aimed to identify a new fungal species by molecular methods and to explore the possible efficacy of the three most common antifungals used in human keratitis in Mexico by performing in vitro analysis. The capacity of this pathogen to cause corneal infection in a murine model was also evaluated.

Methods: The fungal strain was isolated from a patient with a corneal ulcer. To identify the fungus, taxonomic and phylogenetic analyses (nrDNA ITS and LSU data set) were performed. An antifungal susceptibility assay for amphotericin B, itraconazole and voriconazole was carried out. The fungal isolate was used to develop a keratitis model in BALB/c mice; entire eyes and ocular tissues were preserved and processed for histopathologic examination.

Results And Conclusion: This fungal genus has hitherto not been reported with human keratitis in Mexico. We described a new species Purpurecillium roseum isolated from corneal infection. P roseum showed resistance to amphotericin B and itraconazole and was sensitive to voriconazole. In vivo study demonstrated that P roseum had capacity to developed corneal infection and to penetrate deeper corneal tissue. The global change in fungal infections has emphasised the need to develop better diagnostic mycology laboratories and to recognise the group of potential fungal pathogens.
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February 2021

Identification and biofilm development by a new fungal keratitis aetiologic agent.

Mycoses 2019 Jan 16;62(1):62-72. Epub 2018 Oct 16.

Departamento de Microbiología y Proteómica, Instituto de Oftalmología "Fundación Conde de Valenciana", Mexico City, México.

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 × 10  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.
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January 2019

Considerations and consequences of allowing DNA sequence data as types of fungal taxa.

IMA Fungus 2018 Jun 24;9(1):167-175. Epub 2018 May 24.

Museum of Evolution, Uppsala University, Norbyvägen 16, 75236 Uppsala, Sweden.

Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11 International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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June 2018

Fomitiporia cupressicola sp. nov., a parasite on Cupressus arizonica, and additional unnamed clades in the southern USA and northern Mexico, determined by multilocus phylogenetic analyses.

Mycologia 2012 Jul-Aug;104(4):880-93. Epub 2012 Mar 31.

Université catholique de Louvain, Louvain-la-Neuve, Belgium.

Fomitiporia cupressicola sp. nov., found in living Cupressus arizonica, is described on the basis of several collections originating from a high altitude forest in the northern Sierra Madre Occidental, Mexico. The species forms a monophyletic clade, basal to a larger lineage comprising species originating mainly from temperate to Mediterranean areas of the northern hemisphere. The phylogenetic approach in Fomitiporia also revealed multiple unnamed clades within the F. robusta complex in the southern USA and northern Mexico, representing potential species. The status of the F. robusta complex in North America is discussed briefly.
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September 2012