Multilocus differentiation of the related dermatophytes Microsporum canis, Microsporum ferrugineum and Microsporum audouinii

Abstract

Microsporum ferrugineum, an uncommon causative agent of dermatophytosis, has restricted endemicity. Iranian strains suspected to be M. ferrugineum from two patients with tinea were analysed using the rDNA internal transcribed spacer (ITS) region and the partial b-tubulin (BT2) and translation elongation factor 1-a (TEF1) genes. Strains were compared to reference strains to differentiate M. ferrugineum from its relatives Microsporum canis and Microsporum audouinii. Inter-species differences for TEF1 and BT2 were found to be higher than for the ITS region, which is the current molecular standard for species identification in dermatophytes. Intra-species variation was zero for each of the markers. In silico analysis showed that the restriction enzymes BanI and BshNI were together sufficient to differentiate the three species based on TEF1, whereas a two-step digestion was needed with BT2 or the ITS region. The prevalence of M. ferrugineum in clinical samples in Iran appeared to be higher than suspected on the basis of routine phenotypic identification.

Restriction Analysis of β-Tubulin Gene for Differentiation of the Common Pathogenic Dermatophytes

“…M. canis , M. ferrugineum , and M. audouinii are three closely‐related members of the Arthroderma otae complex and it was recently found that interspecies variation of BT2 sequence is higher than ITS for differentiation among the members of A. otae complex, however, the two latter species are uncommon species in Iran and we eliminated them in our study. T. interdigitale alongside T. tonsurans and T. equinum comprise three species correlated to A. vanbreuseghemii teleomorph .…”

Class 1 Integrons and Antibiotic Resistance of Clinical Acinetobacter calcoaceticus–baumannii Complex in Poznań, Poland

“…Class 2 integrons are found with low frequency in various Gram-negative bacteria [25, 26, 39]. In Acinetobacter spp., class 2 integron has been found only in limited number of strains, originated from a hospital in Brazil [7], from hospitals in Iran [10, 29, 33], and from wastewater in China [39]. Class 3 integrons have not been detected in Acinetobacter spp.…”

The first case of onychomycosis in a koala (Phascolarctos cinereus) due to atypical isolates of Microsporum gypseum, a diagnostic challenge

“…Importantly, we did not confine diagnostic analysis to morphology-based experiments only, and so the identity of the infectious isolate was determined as M. gypseum by ITS-sequencing, the golden diagnostic standard [23]. Further sequencing of two novel genetic markers for dermatophytes, BT2 and Tef-1α [11, 26] along with the results of antifungal susceptibility testing indicated that the two isolates belonged to the same strain of M. gypseum which concurrently exhibited two very different morphotypes. Generally, the genetic background of phenotypic variation in most classical dermatophyte species remains unknown and more studies are needed to understand this occurrence.…”

“…To confirm the diagnosis of dermatophytosis and additionally to determine if the etiologic agents represented the same species/strain, the two isolates were subjected to PCR and sequencing by the following primer sets: The universal fungal ITS1/ITS4 primers [10] were used to amplify the DNA fragment covering the internal transcribed spacer regions (ITS1 and ITS2) and the flanking 5.8S subunit of the rRNA gene (rDNA); the pan-dermatophyte primers EF-DermF/EF-DermR [11] were used to amplify translation elongation factor1-α ( Tef-1α ), and the universal fungal primers T1 [12] and Bt2b [13] were used to amplify the beta tubulin ( BT2 ) gene. Interestingly, analysis of all three loci by pairwise sequence alignment revealed that the two strains were identical (100% similarity).…”