(Antofagasta)Prevalence of superficial mycoses in patients attending dermatological consultations in the city of Antofagasta.
Universidad de Antofagasta
Microbiology Unit, Medical Technology Department, Faculty of Health Science, University of Antofagasta, Antofagasta, Chile; Avda. Universidad de Antofagasta #02800
Nicomedes Valenzuela Lopez PhD
Nicomedes Valenzuela Lopez PhD
English, Spanish
4 weeks
Cities/Months Jan Feb Mar Apr May Jun Jul Augt Sep Oct Nov Dec
No No No No No No Yes No No No No No
Type of Research Project
- Clinical Project with Laboratory work
What is the background of the project?
The incidence of the number of mycoses (human infections by fungi) in Chile is still uncertain due to the scarce public health reports in our country. However, nearly a billion people are estimated to have skin, nail and hair fungal infections in the world (Bongomin et al. 2017), and the few studies in this matter in our country have only been performed in other regions of Chile. The study by Cruz et al. (2011) showed that the fungus Trichophyton rubrum was the most frequent agent isolated in superficial mycoses, affecting mostly young women. Currently, there are no studies of the superficial mycoses in Antofagasta, for this reason the present work aims to start the study of fungal infections in two dermatological centers of Antofagasta. To comply with the proposal, we will take samples of hair, nail or skin of patients with suspect of superficial mycoses, after collecting the samples will be isolated in culture media and by direct mounting observation, subsequently, morphological and molecular characterization will be carried out in order to obtain a proper identification of the agent.
What is the aim of the project?
To provide the prevalence and the identification of the fungal agent which causes the superficial mycoses in patients that visit the dermatology center.
What techniques and methods are used?
To collect samples of hair, nail and skin in patients with suspect of mycoses, previously after having their approval in the bioethical concern form, then the sample will be taken by scraping with a scalpel the lesion. In order to identify the fungal isolates traditional techniques in culture media such as Mycosel agar and potato dextrose agar will be inoculated. The morphological features of the vegetative and reproductive structures were studied using an Olympus CH2 light-field microscope (Olympus Corporation, Tokyo, Japan) in wet mounts (lactic acid or cotton–blue lactophenol), and by molecular methods such as PCR (polymerase chain reaction), amplifying phylogenetic markers as internal transcribed spacer region and 28S nrRNA gene and sequencing them. The culture media applied for the isolation are as follows: Mycosel agar (Becton Dickinson, USA), potato dextrose agar (PDA, 20g potato, 20g dextrose, 20g agar, 1L distilled water). The morphological and molecular characterization of the results will be carried out by observing fructification structures using diverse mycological atlases (de Hoog et al. 2001; Guarro et al. 2012) and by amplifying and sequencing the phylogenetic markers of rRNA (LSU and ITS) following the methodology of Valenzuela-López et al. (2017). Once the isolates are grouped at the taxonomic level, they will be derived to the amplification and sequencing of other phylogenetic markers such as: tub2, tef1, rpb2, etc. (Valenzuela-Lopez et al. 2018) To determine the phylogenetic relationships of the species identified by multi-locus sequence analysis, employing different computational software. The phylogenetic reconstructions and alignments will be performed using Maximum likelihood (ML) and Bayesian (BI) inference analysis methods, using the MEGA v6.0 program (Tamura et al. 2013) and MrBayes version 3.1.2. (Huelsenbeck & Ronquist 2001), as well as, other platforms such as CIPRES Science Gateway (Miller et al. 2012).
What is the role of the student?
What are the tasks expected to be accomplished by the student?
The student will learn about the preparation of culture media used for fungal isolation as well as their morphological identification. He or She will have to learn how to prepare slides for microscopic observation. In addition, he will learn on molecular biology performing extraction of DNA and amplifying phylogenetic markers by PCR, sequencing the PCR product and verifying it in the computational programs of sequences edition and how to prepare alignments in order to obtain the phylogenetic reconstruction. In addition, the student has the opportunity to take samples of the clinical presentation of mycoses that the dermatologist will derive to mycological study.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
Theoretical teaching will be held by the tutor explaining basic procedures of microbiology lab, fungi theorics, biosafety procedures, and molecular biology. In addition, the student should prepare a seminar in a meeting.
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a presentation
- The student will prepare a scientific report
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
Knowledge in Biology, Microbiology. Biosafety, and use of the basic procedure of laboratory.
Are there any legal limitations in the student’s involvement
Type of students accepted
This project accepts:
- Medical students
- Students in biomedical fields
- Valenzuela-Lopez N; Sutton DA; Cano-Lira JF; et al. 2017. Coelomycetous fungi in the clinical setting: Morphological convergence and cryptic diversity. J Clin Microbiol. 2017;55:552–567.
- Valenzuela-Lopez N; Cano-Lira JF; Stchigel AM; Guarro J. DNA sequencing to clarify the taxonomical conundrum of the clinical coelomycetes. Mycoses. 2018;61:708–717.
- Martin-Gomez MT; Valenzuela-Lopez N; Cano-Lira JF. Knufia epidermidis: a rare finding in a paediatric dermatological sample. Clin Microbiol Infect. 2018.
- Valenzuela-Lopez N; Cano-Lira JF; Stchigel AM; Rivero-Menendez O; Alastruey-Izquierdo A; Guarro J. Neocucurbitaria keratinophila: an emerging opportunistic fungus causing superficial mycosis in Spain. Med Mycol. 2018.
- Garcia-Hermoso D; Valenzuela-Lopez N; Rivero-Menendez O; Alastruey-Izquierdo A; Guarro J; Cano-Lira JF; Stchigel AM; French Mycoses Study Group. Diversity of coelomycetous fungi in human infections: A 10-y experience of two European reference centres. Fungal Biol. 2019;123:341–349.