Anti-MRSA Activity of Actinomycin X2 and Collismycin A Produced by Streptomyces globisporus WA5-2-37 From the Intestinal Tract of American Cockroach (Periplaneta americana)

Abstract

Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) is recognized as one of the serious pathogen that causes acquired infections worldwide. Its emerging need to discover novel, safe and potent anti-MRSA drugs. In this study, primary screening by anti-MRSA activity assay found one strain WA5-2-37 isolated from the intestinal tract of <i>Periplaneta americana</i>, exhibited great activity against MRSA ATCC 43300. The strain WA5-2-37 produced actinomycin X₂ and collismycin A which showed strong inhibition of MRSA with minimum inhibitory concentration (MIC) values of 0.25 and 8 μg/mL. The structures of the pure compounds were elucidated by analysis of mass spectrometry (MS), ¹H and ¹³C nuclear magnetic resonance (NMR). The strain WA5-2-37 was considered as <i>Streptomyces globisporus</i> on the basis of morphological characteristics, genotypic data, and phylogenetic analysis. This is the first reported naturally occurring strain of <i>S. globisporus</i> isolated from the intestinal tract of <i>P. americana</i>, whereas it has almost been found from plants, marine, and soil previously. Moreover, <i>S. globisporus</i> has not been reported to produce any anti-MRSA substances previously, such as actinomycin X₂ and collismycin A. In conclusion, the insect-derived strain of <i>S. globisporus</i> WA5-2-37 was considered of great potential as a new strain of producing actinomycin X₂, collismycin A or other anti-MRSA compounds.