Papers by Mohammad Najafzadeh
Medical Mycology Official Publication of the International Society For Human and Animal Mycology, 2012
Trichophyton tonsurans and T. equinum are two closely related sister species of dermatophytes, bu... more Trichophyton tonsurans and T. equinum are two closely related sister species of dermatophytes, but differ in their preferred hosts, i.e., humans or horses, respectively. Routine procedures for their identifi cation depend on studies of their phenotypic, physiological and biochemical characteristics, which are laborious and may yield ambiguous results. Molecular methods using rDNA ITS also had been judged to be insuffi ciently discriminatory. In the present study two genetic markers were sequenced in addition to the ITS region, i.e., partial β -tubulin ( BT2 ) and translation elongation factor 1-α ( TEF1 ). The TEF1 locus revealed a consistent differences in a 13 bp indel and an additional SNP between the two species, along with a single base substitution in BT2 and one ITS1, enabling unambiguous distinction of the two taxa. RFLP targeting the ITS region was evaluated as a potential tool for routine screening of suspected isolates of T. tonsurans and T. equinum .
Frontiers in Microbiology, 2015
Sporothrix infections are emerging as an important human and animal threat among otherwise health... more Sporothrix infections are emerging as an important human and animal threat among otherwise healthy patients, especially in Brazil and China. Correct identification of sporotrichosis agents is beneficial for epidemiological surveillance, enabling implementation of adequate public-health policies and guiding antifungal therapy. In areas of limited resources where sporotrichosis is endemic, high-throughput detection methods that are specific and sensitive are preferred over phenotypic methods that usually result in misidentification of closely related Sporothrix species. We sought to establish rolling circle amplification (RCA) as a low-cost screening tool for species-specific identification of human-pathogenic Sporothrix. We developed six species-specific padlock probes targeting polymorphisms in the gene encoding calmodulin. BLAST-searches revealed candidate probes that were conserved intraspecifically; no significant homology with sequences from humans, mice, plants or microorganisms outside members of Sporothrix were found. The accuracy of our RCA-based assay was demonstrated through the specificity of probe-template binding to 25 S. brasiliensis, 58 S. schenckii, 5 S. globosa, 1 S. luriei, 4 S. mexicana, and 3 S. pallida samples. No cross reactivity between closely related species was evident in vitro, and padlock probes yielded 100% specificity and sensitivity down to 3 × 10(6) copies of the target sequence. RCA-based speciation matched identifications via phylogenetic analysis of the gene encoding calmodulin and the rDNA operon (kappa 1.0; 95% confidence interval 1.0-1.0), supporting its use as a reliable alternative to DNA sequencing. This method is a powerful tool for rapid identification and specific detection of medically relevant Sporothrix, and due to its robustness has potential for ecological studies.
The first step in any biodiversity study is the establishment of species borderlines. Morphology ... more The first step in any biodiversity study is the establishment of species borderlines. Morphology in the Chaetothyriales is essential for the ecology and survival for the organism, but is often less significant to classify species. Therefore the development of a molecular species concept is necessary. This concept is primarily based on genealogical concordance of several gene trees made for the set of species under investigation. Fonsecaea is defined by absence of budding cells, sympodial conidiogenesis and conidia arranged in short chains. Fonsecaea pedrosoi was first isolated in 1913 as an etiological agent of chromoblastomycosis by Pedroso and later described and named by Brumpt (1922) and Negroni (1936). On the basis of ribosomal DNA internal transcribed spacer (ITS) sequence data, two species were recently recognized within the genus, i.e., F. pedrosoi and F. monophora. Traditionally the genus included a third species, (Carrion 1950). This taxon is now known to be one of the mor...
The genus Exophiala contains numerous potential opportunists or pathogens of immunocompetent huma... more The genus Exophiala contains numerous potential opportunists or pathogens of immunocompetent humans. Systemic species are able to grow at 37–40 °C, which is taken to be one of the main virulence factors in Chaetothyriales. However, during the last few decades, many Exophiala isolates have been recovered that consistently lacked thermotolerance, but nevertheless were involved in animal, sometimes in human disease. A neglected group of infections was found in fish and amphibians, occasionally also in invertebrates. We describe a rapid and sensitive assay for detection and identification of pathogenic fungi without sequencing. The method is presented with waterborne Exophiala species causing disease in cold-blooded animals as a model. The ITS rDNA region of eight Exophiala species (E. superficiale, E. opportunistica, E. pisciphila, E. aquamarina, E. mesophila, E. angulospora, E. cancerae, E. equina) was sequenced and aligned in view of designing eight specific padlock probes to be used...
Introduction and objectives: These days fungal infection increase widely .Candida vaginit is the ... more Introduction and objectives: These days fungal infection increase widely .Candida vaginit is the second common infection. In average at least 75% of women one time have involved by Candida vulvovaginit, 85% to 90% of vaginal infected caused by Candida albicans. Aim of this study is recognition of Candida species in women refrred to Ghayem hospital of Mashhad by Crom agar, Cron meal agar and germ tube test. Material and methods: At first in order to see yeast used Lactophenol solution blue and then cultured in sabourd 4% dextrose agar after that used the colonies to cultured strightly on cron meal agar and crom agar at last incubate for 48 hours at 30C, also used human serum diluted with ½ normal salin and incubate for 2 or 3 hours to see germ tube. Results: From 62 samples, 85% has germ tube,72% in corn meal agar produce chalmydospore and blastospors and in crom agar %84/1 Candida albicans (green), %11/4 Candida gelabrata (purple) and 4/5 white for other species. Age between 23 to 3...
Mucormycosis is a rare life-threatening opportunistic infection caused by several mold fungi in t... more Mucormycosis is a rare life-threatening opportunistic infection caused by several mold fungi in the order Mucorales. Generally, species in the Rhyzopus, Mucor, Rhyzomucor, Absidia and Cunninghamella genera are most often implicated. Different clinical forms including: Rhinocerebral , Pulmonary, Inguinal, Gastrointestinal, Cutaneous etc.., occur in association with underlying diseases or risk factors. The examples are: Diabetic Ketoacidosis (DKA), Neutropenia ,Hematological Malignancies, hematopoietic stem cell transplant and solid organ transplant recipients, AIDS, Sever Burns, Malnutrition, Low birth weight and Long-term use of steroids, deferoxamine etc.. Because of its rapid progression and high mortality, early diagnosis and aggressive treatment offer the only chance to increase the survival rate. Since, early initiation of antifungal therapy is beneficial in the outcome of invasive mucormycosis; therefore, development of improved diagnostic methods should become an important go...
Medical mycology, 2014
We investigated the resolving power of the beta tubulin protein-coding gene (BT2) for systematic ... more We investigated the resolving power of the beta tubulin protein-coding gene (BT2) for systematic study of dermatophyte fungi. Initially, 144 standard and clinical strains belonging to 26 species in the genera Trichophyton, Microsporum, and Epidermophyton were identified by internal transcribe spacer (ITS) sequencing. Subsequently, BT2 was partially amplified in all strains, and sequence analysis performed after construction of a BT2 database that showed length ranged from approximately 723 (T. ajelloi) to 808 nucleotides (M. persicolor) in different species. Intraspecific sequence variation was found in some species, but T. tonsurans, T. equinum, T. concentricum, T. verrucosum, T. rubrum, T. violaceum, T. eriotrephon, E. floccosum, M. canis, M. ferrugineum, and M. audouinii were invariant. The sequences were found to be relatively conserved among different strains of the same species. The species with the closest resemblance were Arthroderma benhamiae and T. concentricum and T. tons...
ABSTRACT Nattrassia mangiferae is a plant pathogen that is also known as cause of superficial, su... more ABSTRACT Nattrassia mangiferae is a plant pathogen that is also known as cause of superficial, subcutaneous and disseminated infections in humans. Reports of human infections are extremely rare in Iran. They are characterized by development of dark colored filamentous hyphae in the involved tissues and their colonies are narrow branching and wide subhyaline to dark brown hyphae which fragmented to one-septate or no-septate arthroconidia. To our knowledge, this study describe the first case of phaeohyphomycosis sinusitis caused by N. mangiferae in an immunocompetent 20-year-old man who presented with maxillary sinusitis, frequent headaches in the forehead, nasal congestion, post-nasal discharge (PND) and dyspnea. The diagnostic workup includes computed tomography scan followed by direct microscopic examination and culture of tissue biopsy and sinus discharge specimens. We observed bilateral obstruction of maxillary sinus and mucosal hypertrophy in CT scan; and presence of septate, branched, and subhyaline to dark colored hyphae in direct examination; and rapid growth of the olivaceous grey to black colonies with aerial strands of greyish black mycelia with one-septate to no-septate arthroconidia on mycological media. The patient was treated with Amphotericin B that less than two weeks improved gradually.
Earth Science Informatics, 2014
ABSTRACT An improved neuro-fuzzy based group method of data handling using the particle swarm opt... more ABSTRACT An improved neuro-fuzzy based group method of data handling using the particle swarm optimization (NF-GMDH-PSO) is developed as an adaptive learning network to predict the localized scour downstream of a sluice gate with an apron. . The input characteristic parameters affecting the scour depth are the sediment size and its gradation, apron length, sluice gate opening, and the flow conditions upstream and downstream of the sluice gate. Six non-dimensional parameters were yielded to define a functional relationship between the input and output variables. The training and testing of the NF-GMDH network are performed using published scour data from the literature. The efficiency of the training stages for the NF-GMDH-PSO is investigated. The testing results for the NF-GMDH network are compared with the traditional approaches based on regression method. A sensitivity analysis is carried out to assign the most significant parameter for the scour prediction. The results showed that the NF-GMDH-PSO network produced lower error in scour prediction than all other models.
Medical mycology, Jan 30, 2014
Intra- and interspecies variations of the translation elongation factor 1-α (Tef-1α) gene were ev... more Intra- and interspecies variations of the translation elongation factor 1-α (Tef-1α) gene were evaluated as a new identification marker in a wide range of dermatophytes, which included 167 strains of 30 species. An optimized pan-dermatophyte primer pair was designed, and the target was sequenced. Consensus sequences were used for multiple alignment and phylogenetic tree analysis and the levels of intra- and interspecific nucleotide polymorphism were assessed. Between species, the analyzed part of the Tef-1α gene varied in length from 709 to 769 nucleotides. Significant numbers of species including Trichophyton rubrum, T. tonsurans, T. schoenleinii, T. concentricum, T. violaceum, Epidermophyton floccosum, Microsporum ferrugineum, M. canis, M. audouinii, T. equinum, T. eriotrephon, and T. erinacei were invariant in Tef-1α and had sufficient barcoding distance with neighboring species. Although overall consistency was found between ITS phylogeny as the current molecular marker of derma...
Journal of Medical Microbiology, 2014
The study describes isolation of Neoscytalidium dimidiatum from a case of eosinophilic fungal rhi... more The study describes isolation of Neoscytalidium dimidiatum from a case of eosinophilic fungal rhinosinusitis (EFRS). The isolate was identified by routine mycological methods and confirmed by DNA sequencing of the internal transcribed spacer (ITS) region of rDNA. To our knowledge, this is the first report of its kind from Iran.
PLoS ONE, 2012
Members of the fungal genus Fonsecaea causing human chromoblastomycosis show substantial geograph... more Members of the fungal genus Fonsecaea causing human chromoblastomycosis show substantial geographic structuring. Genetic identity of clinical and environmental strains suggests transmission from plant debris, while the evolutionary processes that have led to spatially separated populations have remained unexplained. Sequences of ITS, BT2, ACT1, Cdc42, Lac and HmgA were analyzed, either by direct sequencing or by cloning. Thirty-seven clinical and environmental Fonsecaea strains from Central and South America, Asia, Africa and Europe were sequenced and possible recombination events were calculated. Phylogenetic trees of Cdc42, Lac and HmgA were statistically supported, but ITS, BT2 and ACT1 trees were not. The Standardized Index of Association (I A S ) did not detect recombination (I A S = 0.4778), neither did the Phi-test for separate genes. In Fonsecaea nubica non-synonymous mutations causing functional changes were observed in Lac gene, even though no selection pressures were detected with the neutrality test (Tajima D test, p.0.05). Genetic differentiation of populations for each gene showed separation of American, African and Asian populations. Strains of clinical vs. environmental origin showed genetic distances that were comparable or lower than found in geographic differentiation. In conclusion, here we demonstrated clonality of sibling species using multilocus data, geographic structuring of populations, and a low functional and structural selective constraint during evolution of the genus Fonsecaea.
Mycopathologia, 2017
Occurrence and diversity of dermatophyte mycoflora in 298 soil samples from Ahvaz, Southwest of I... more Occurrence and diversity of dermatophyte mycoflora in 298 soil samples from Ahvaz, Southwest of Iran was investigated by using the hair-baiting technique. The samples were collected during spring (n = 210) and autumn (n = 88) of 2015, and the fungal isolates were identified based on the macro- and micro-morphology of colonies and with further ITS-rDNA RFLP and sequencing. Totally, 60 soil samples (20.1%) were positive for dermatophyte growth whose pH varied from 7.0 to 7.9. The highest (26.6%) and the lowest (14.3%) recovery rates were from the animal resorts and the streets soils samples, respectively. Seasonally, 16.7% of the spring samples and 28.4% of the autumn samples were positive. Based on molecular identification, three species of two genera were identified viz. M. fulvum (n = 57), M. canis (n = 2) and zoophilic Trichophyton interdigitale (n = 1). As a specific goal in the study, differentiation of the species in Microsporum gypseum complex was established by measuring the mean length and width of macroconidia in some strains of M. gypseum, M. fulvum and M. incurvatum. Mean size for macroconidia length and width in three species showed that M. gypseum and M. incurvatum can morphologically be differentiated from M. fulvum but not from each other. M. fulvum was the most abundant species isolated from the soils of Ahvaz; however, to comprehensively specify the distribution pattern of geophilic dermatophytes in the soils of this city further investigations are needed. Identification based on micro-morphometric is not effective for species distinction in M. gypseum complex, while molecular procedures based on sequencing of certain DNA regions are the most reliable and applicable strategies for this purpose.
Mycopathologia, 2013
Dermatophytoses are considered to be one of the major public health problems in the world and are... more Dermatophytoses are considered to be one of the major public health problems in the world and are among the most commonly diagnosed skin diseases in Iran. In spite of improved personal hygiene and living environment, dermatophytosis continues to spread and persist. To determine the prevalence of dermatophytosis and their etiologic agents in Mashhad (Iran), five hundred and sixty patients suspected to have fungal infection were studied. Subjects who participated in this study were 330 males and 230 females ranged in age from 4 months to 70 years with a mean age of about 25.5 years. Clinical materials including skin scraping, hair and scalp sample, nail clipping and subungual debris were collected. All of the specimens were assessed by direct examination and culture. Of 560 patients, 166 (29.6 %) had
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Papers by Mohammad Najafzadeh