title: Consistent high prevalence of Exophiala dermatitidis, a neurotropic opportunist, on railway sleepers.
abstract: Environmental isolation of black yeasts potentially causing human disorders is essential for understanding ecology and routes of infection. Several Exophiala species show prevalence for man-made environments rich in monoaromatic compounds, such as creosote-treated or petroleum-stained railway sleepers. Ambient climatic conditions play a role in species composition in suitable habitats. Therefore, the aim of the present study was to establish the composition of Exophiala species in railway stations as a potential source of human infections in a subtropical region with evaluation of their antifungal susceptibility profiles. We examined 150 railway samples using cotton swabs moistened with sterile physiological saline. Black yeasts and relatives were selected on theirs colony morphology and identified based on ITS rDNA sequencing. Overall, 36 (24%) of samples were positive for black yeast-like fungi, i.e., Exophiala dermatitidis (n=20, 55.6%) was predominant, followed by E. phaeomuriformis (n=9, 25%), E. heteromorpha (n=5, 13.9%), and E. xenobiotica (n=2, 5.6%). Massive contaminations of E. dermatitidis were seen on railway sleepers on creosoted oak wood at the region close to the sea level, while in cold climates were primarily contaminated with clinically insignificant or rare human opportunists (E. crusticola). It seems that, high temperature and humidity are significant effect on species diversity. Moreover, the MIC results for all E. dermatitidis and E. phaeomuriformis strains revealed the widest range and the highest MICs to caspofungin (range 1-16mg/L, Geometric mean 4.912mg/L), and the lowest MIC for posaconazole (0.016-0.031mg/L, G mean 0.061mg/L). However, their clinical effectiveness in the treatment of Exophiala infections remains to be determined.
authors.affiliation: Department of Medical Parasitology and Mycology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: S A
authors.initials: SA
authors.lastname: Yazdanparast
authors.affiliation: Department of Microbiology, Sari Branch, Islamic Azad University, Sari, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Mohseni
authors.affiliation: CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands.
authors.forename: G S
authors.initials: GS
authors.lastname: De Hoog
authors.affiliation: Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: N
authors.initials: N
authors.lastname: Aslani
authors.affiliation: Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Sadeh
authors.affiliation: Invasive Fungi Research Centre (IFRC), School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Electronic address: badalii@yahoo.com.
authors.forename: H
authors.initials: H
authors.lastname: Badali
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D004271:DNA, Fungal / Q000235:genetics; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005093:Exophiala / Q000235:genetics / Q000302:isolation & purification*; D006703:Ill-Housed Persons / Q000706:statistics & numerical data*; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D016533:Mycological Typing Techniques; D009474:Neurons / Q000382:microbiology; D060446:Phaeohyphomycosis / Q000453:epidemiology* / Q000382:microbiology*; D015995:Prevalence; D011890:Railroads / Q000706:statistics & numerical data; D012111:Residence Characteristics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D018523:Tropism
chemical_list: D000935:Antifungal Agents; D004271:DNA, Fungal
keywords: Black yeast and relatives; Composés monoaromatiques; Espèces d’Exophiala; Exophiala species; Levure noire et apparentés; Monoaromatic compounds; Railway sleepers; Traverses de chemin de fer