الفهرس 
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Abstract
Actinomycetes from different habitats were isolated and purified and studied for their anticandidal activities against some multi-drug resistant pathogenic candida. In our study, forty actinomycete isolates were isolated on starch-nitrate agar medium from different habitats (soil, rhizosphere and marine water samples). The isolated actinomycete isolates were identified according to their different colony morphology, color variations and the color of aerial and substrate mycelium on starch-nitrate medium based on Bergey’s Manual of determinative Bacteriology. The isolates were screened for their anticandidal activity against nine multi-drug resistant candida species (C. lustitaniae, C. tropicalis, C. parapsilosis, C. kefyr, C. glabrata, C. dublinesis, C. albicans, and C. krusie) by using well agar diffusion method. Out of 40 isolates, the promising results for anticandidal activity were recorded by isolates NO. 7 against (C. lusitaniae, C. tropicalis, C. parapsilosis, C. kefyr, C. galabrata, C.dublinesis, C. albicans), isolates NO. 12 against (C. lustitaniae, C. tropicalis, C.parapsilosis, C.kefyr, C. dublinesis C. krusie and C. albicans) and isolates NO. 35 against C. lustitaniae, C. parapsilosis, C. dublinesis, and C. albicans) where the diameter of inhibition zones ranged from 11-18, 14-15 and 10-16 mm with isolates NO. 7, 12 and 35 respectively, therefore, they were selected for further work. Scanning electron microscopy in addition to morphological, physiological, biochemical characters indicated that the selected isolates NO. 7, 12 and 35 belonging to the genus Streptomyces, the molecular identification confirmed and revealed that our tested sequences of the selected isolates NO. 7, 12 and 35 had 100%, 83% and 99% similarity PCR sequences with their respective species rochei, S. alboverticillatus and S. djakartensis respectively. Culture conditions of the selected isolates were optimized for maximizing growth and anticandidal activity. The results under the optimized conditions of incubation period, pH, temperature, carbon and nitrogen sources were recorded the maximum mycelial dry weight and significant anticandidal activities of the three identified actinomycetes. S. rochei recorded the highest inhibitory effect against C. albicans, C. lustitaniae followed by C. tropicalis, where the diameter of inhibition zones was 29.6, 29 and 27.3 mm respectively. S. alboverticillatus exhibited the highest inhibitory effect against C. tropicalis, C. lustitaniae, and C. dublinesis where the diameter of inhibition zones was 21.6, 20.3 and 20.3 mm respectively. And S. djakartensis showed the highest inhibitory effect against C. lustitaniae and C. tropicalis where the diameter of inhibition zones were 22, 21 and 20 mm respectively. The inhibitory agents of the selected actinomycetes were extracted using ethyl acetate solvent, TLC analysis of the selected isolates (S. rochei, S. alboverticillatus and S. djakartensis) extracts showed one band for each extract having 0.6, 0.6 and 0.7 respectively. The UV spectrum of the antimicrobial materials produced by the selected actinomycete S. rochei, S. alboverticillatus and S. djakartensis was found to have a maximum absorption at 310, 228, and 379 nm respectively. IR spectroscopy of the materials produced by the selected isolates indicated the presence of many functional groups in the extract as OH, , and . Toxic cyano group (C≡N; 2220-2260 ) and acetylenic group (C≡C; 2100- 2260 ) are absent as an indicator of the safety of the materials produced. The produced materials by the selected isolates were identified by GC-MS technique. The most active antimicrobial materials produced by S. rochei, S. alboverticillatus that have antimicrobial activity were oleic acid and 9-octadecenoic acid, where the most abundant materials produced by S. djakartensis that have antimicrobial activity were 9- Octadecenamide (z), Phthalic acid, bis (7-methyloctyl) ester and 13-Docosenamide (z). Our results revealed that the minimal inhibitory concentrations of the active antifungal materials of S. rochei against C. albicans, was 6.25 mg/ml where the diameter of inhibition zone was 15.0 mm. In our study, antimicrobial activity of the active materials of the identified actinomycete against infection of mice wound by MDR C.albicans was studied. The results showed significant inhibitory effect of the active antimicrobial materials of S. rochei at MIC and miconaz antibiotic against microbial MDR C.albicans, infecting mice skin wounds comparing with the untreated positive control. Out of the treatments, the treatment with the antimicrobial materials of S. rochei recorded the highest inhibitory effect against the infected wound with microbial MDR C. albicans where the percentage of wound healing reached to 100% after 17 day. where the percentage (%) of skin wound healing of the treated skin with miconaz antibiotic ranged from 50-85 from the 4th to the 17th day. The lowest redness of wound and moderate hair growth were observed after 7-14 days of treatment by the active antimicrobial materials in the extract of S. rochei. Furthermore, at the end of the experimental period after 21 days, complete disappearance of inflammation and considerable growth of hair were detected. The histopathological investigation of healthy mice skin tissues (Negative control) showed normal epidermis as the keratinized fibers of stratum corneum were regularly arranged, appeared condensed without any disruption and the dermis appeared normal with normal fibroplasts. Whereas, the histological section of the positive control group infected and untreated showed round, short elongated cells and some thread swelling within the stratum corneum where it’s keratinized fibers appear loose and disrupted, and the dermis showed chronic inflammatory cellular infiltrate mainly formed of lymphocytes and plasma cells. In comparison with control, the histopathological investigation of mice skin tissues treated with S. rochei extract possessed no thread swelling, no significant toxic effects; the skin tissue appeared with normal epidermis as keratinized fibers of stratum corneum were regularly arranged, appeared condensed without any disruption and the dermis appeared normal with minimal inflammatory cellular infiltrate .On the other hand, miconaz treated skin possessed un normal epidermis as the keratinized fibers of stratum corneum still showed some disruption and few thread swelling of candidiasis were remained and the dermis showed edema with some inflammatory cellular infiltrate of lymphocytes. Based on this study, the bioactive antimicrobial materials in the extract of the selected actinomycete have been recognized as promising antifungal materials against MDR pathogenic candida. In vivo study, antimicrobial activity of the extract of actinomycete against microbial infection is very limited so more studies should be carried out to control the microbial infection of human skin wound.