br Introduction Increasing number of mycosis

Introduction Increasing number of mycosis infections has been reported during the past several years because of the rise in the number of immuno-compromised individuals in subtropical and tropical countries with high mortality and morbidity [1], [2]. Trichophyton mentagrophytes, Trichophyton rubrum and Scopulariopsis species are the major dermatophytes which are more commonly involved in keratinized tissues and other related infections in humans and animals such as ring worm, tinea captis, tinea manus, tinea unguinum, tinea pedis, tinea inguinalis, psoriasis, onychomycosis and dermatophytosis [3], [4]. Aspergillus species are an environmentally unfriendly phytopathogenic and toxinogenic mold, which are the predominant causative agents of polyketides such as Aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) G2 (AFG2) and cyclopiazonic Tranexamic Acid [5]. Agricultural crops such as cottonseed, peanut and tree nuts are highly prone to aflatoxin contamination, which is extremely carcinogenic, teratogenic, mutagenic and immune-suppressant when ingested in little amount by humans and animals [6], [7]. Botrytis cinerea is one of the major necrotrophic fungus commonly called as grey mold belonging to the family Sclerotiniaceae. It infects more than 200 food crops with great commercial values worldwide resulting in great agricultural and economic losses [8], [9], [10]. Worldwide, every year over 15 million deaths are attributed to the evolution of new infectious fungal diseases or to the re-emergence of old pathogens with new resistance against the existing antibiotics as classified by the WHO [11], [12]. There are also many side effects of antibiotics causing unhealthy situations such as carcinogenicity, hormonal imbalance, residual toxicity, teratogenicity and spermatotoxicity [13], [14]. Further, microbiological and clinical failures are still very high [15], [16]. Hence, it is essential to identify effective novel antifungal compounds with broad-spectrum activity against dermatophytes and phyto-fungal pathogens. To overcome these problems, microbial-based medicines have attracted the attention of researchers as potential alternative source of drug molecules to treat variety of ailments. Terrestrial Streptomyces is the prime antibiotic producing prokaryotic Gram-positive bacterium among the actinomycetes in pharmaceutical industry; more than 60% of the nearly 6000 antibiotics of microbial origin are from the family Streptomycetaceae. Accordingly, Streptomyces as prolific sources of a larger number and wider variety of novel lead compounds have been continuously screened than any other actinomycetes genus. However, the unearthing of novel bioactive molecules produced by Streptomycetaceae from common and ubiquitous sources such as soil has been declining [17], [18]. In this context, the present investigation was undertaken to isolate soil Streptomyces with antifungal properties.
Materials and methods
Results and discussion
Conclusion Our study showed that the ethyl acetate extract of Streptomyces collinus BG4 and the isolated compound phenyl acetic acid had significant antifungal activities against the dermatophytes and phytopahtogenic fungi. It is concluded that Streptomyces derived auxin is a promising candidate for further studies to control phytopathogenic fungi and dermatophytes. Therefore, further detailed studies and preclinical treatment of the active compound will pave the way for its pharmaceutical utilities in the near future.
Disclosure of interest
Acknowledgement The authors are thankful to the Defence Research and Development Organization (DRDO), Govt. of India, (Ref. No: ERIP/ER/1004554M/01/1357) for financial support through a project. They are also grateful to Entomology Research Institute for the facilities. They also extend their appreciation to the International Scientific Partnership Program, ISPP, at King Saud University for partially funding this research work through ISPP#0020.