In Vitro Evaluation of Enzymatic and Antifungal Activities of Soil-Actinomycetes Isolates and Their Molecular Identification by PCR

BACKGROUND: Human cutaneous infection caused by a homogeneous group of keratinophilic fungi called dermatophytes. These fungi are the most common infectious agents in humans that are free of any population and geographic area. Microsporum canis is a cause of dermatophytosis (Tinea) in recent years in Iran and atypical strain has been isolated in Iran. Its cases occur sporadically due to M. canis transmission from puppies and cats to humans. Since this pathogenic dermatophyte is eukaryotes, chemical treatment with antifungal drugs may also affect host tissue cells. OBJECTIVES: The aim of the current study was to find a new antifungal agent of soil-Actinomycetes from Kerman province against M. canis and Actinomycete isolates were identified by PCR. MATERIALS AND METHODS: A number of hundred Actinomycete isolated strains were evaluated from soil of Kerman province, for their antagonistic activity against the M. canis. M. canis of the Persian Type Culture Collection (PTCC) was obtained from the Iranian Research Organization for Science and Technology (IROST). Electron microscope studies of these isolates were performed based on the physiological properties of these antagonists including lipase, amylase, protease and chitinase activities according to the relevant protocols and were identified using gene 16SrDNA. RESULTS: In this study the most antagonist of Actinomycete isolates with antifungal activity against M. canis isolates of L1, D5, Ks1m, Km2, Kn1, Ks8 and Ks1 were shown in vitro. Electron microscopic studies showed that some fungal strains form spores, mycelia and spore chain. Nucleotide analysis showed that Ks8 had maximum homology (98%) to Streptomyces zaomyceticus strain xsd08149 and L1 displayed 100% homology to Streptomyces sp. HVG6 using 16SrDNA studies. CONCLUSIONS: Our findings showed that Streptomyces has antifungal effects against M. canis

Antifungal activity of terrestrial Streptomyces rochei strain HF391 against clinical azole -resistant Aspergillus fumigatus

Background and Purpose: Actinomycetes have been discovered as source of antifungal compounds that are currently in clinical use. Invasive aspergillosis (IA) due to Aspergillus fumigatus has been identified as individual drug-resistant Aspergillus spp. to be an emerging pathogen opportunities a global scale. This paper described the antifungal activity of one terrestrial actinomycete against the clinically isolated azole-resistant A. fumigatus. Materials and Methods: Soil samples were collected from various locations of Kerman, Iran. Thereafter, the actinomycetes were isolated using starch-casein-nitrate-agar medium and the most efficient actinomycetes (capable of inhibiting A. fumigatus) were screened using agar block method. In the next step, the selected actinomycete was cultivated in starch-casein- broth medium and the inhibitory activity of the obtained culture broth was evaluated using agar well diffusion method. Results: The selected actinomycete, identified as Streptomyces rochei strain HF391, could suppress the growth of A. fumigatus isolates which was isolated from the clinical samples of patients treated with azoles. This strain showed higher inhibition zones on agar diffusion assay which was more than 15 mm. Conclusion: The obtained results of the present study introduced Streptomyces rochei strain HF391 as terrestrial actinomycete that can inhibit the growth of clinically isolated A. fumigatus