The increasing use of antibiotics has led to the development of drug-resistant microorganisms. The emergence of resistant strains has compromised the treatment and control of infectious diseases. As a result

No abstract

Antibiotic-resistant strains are a global health-threatening problem. Drug-resistant microbes have compromised the control of infectious diseases. Therefore, the search for a novel class of antibiotic drugs is necessary. Streptomycetes have been described as the richest source of bioactive compounds, including antibiotics. This study was aimed to characterize the antibacterial compounds of Streptomyces sp. PJ85 isolated from dry dipterocarp forest soil in Northeast Thailand. The 16S rRNA gene sequence and phylogenetic analysis showed that PJ85 possessed a high similarity to Streptomyces actinomycinicus RCU-197T of 98.90%. The PJ85 strain was shown to produce antibacterial compounds that were active against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). The active compounds of PJ85 were extracted and purified using silica gel column chromatography. Two active antibacterial compounds, compound 1 and compound PJ85_F39, were purified and characterized with spectroscopy, including liquid chromatography and mass spectrometry (LC–MS). Compound 1 was identified as actinomycin D, and compound PJ85_F39 was identified as dihomo-γ-linolenic acid (DGLA). To the best of our knowledge, this is the first report of the purification and characterization of the antibacterial compounds of S. actinomycinicus.

In this study, an antimicrobial-producing Actinomycetes PJ90 was isolated from forest soil in Suranaree University of Technology, Nakhon Ratchasima, Thailand. The morphological characteristics and 16S rRNA gene analysis revealed that isolate PJ90 could be classified as Streptomyces triostinicus. The isolate PJ90 exhibited antimicrobial activity against Staphylococcus aureus TISTR1466, Staphylococcus epidermidis TISTR518, Bacillus subtilis TISTR008, Candida albicans TISTR5779, Candida tropicalis TISTR5174 and Saccharomyces cerevisiae TISTR5049. To our best knowledge, this study constitutes the first anti-bacterial and anti-yeast activities of Streptomyces triostinicus isolated from soil in Thailand.