Abstract
An actinomycete, designated as CMU-PNK470, was isolated from the soil in Phanangkoi cave in northern Thailand and subjected to phenotypic and genotypic characterization. Morphological and chemical properties indicated that this isolate belonged to the genus Spirillospora. Phylogenetic analysis based on 16S rRNA gene sequencing confirmed its placement in the genus Spirillospora and it was most closely related to Spirillospora albida (98.86%). This is the first reported isolation of Spirillospora albida from a cave habitat. The crude extract of this strain showed antimicrobial activity against three Gram-positive bacteria, Bacillus cereus and Methicillin-resistant Staphylococcus aureus with a MIC value of 23.1 μg/ml and Paenibacillus larvae with a MIC value of 185 μg/ml. It also reduced the number of viable Human Small lung cancer cells (NCI-H187) to less than 50% at a concentration of 10.18 μg/ml.
