Isolation and molecular detection of endophytic actinomycetes Nocardiopsis dassonvillei DMS 1 (MH900216) from marine sea grasses with bacterial inactivation

In recent years, new antibiotics have been discovered around the world in order to inhibit multi-drug resistant (MDR) pathogens. To overcome this problem, marine actinomycetes are an alternative choice for producing new bioactive compounds that inhibit MDR bacteria. The typical endophytic actinomycete (EA) Nocardiopsis dassonvillei (N. dassonvillei) DMS 1 (MH900216) was isolated from marine Sea grasses by surface sterilization method. After surface sterilization, it was confirmed that the pure, dry, white-colored spore producing colonies emerged from the internal tissue of the Sea grasses. The crude extract of N. dassonvillei DMS 1 (MH900216) demonstrated 8- and 10-mm zones of inhibition against A. baumannii and K. pneumoniae, respectively. The composition of N. dassonvillei DMS 1 (MH900216) with potential anti-bacterial properties was studied by GC-MS analysis and exhibited 22 chemical compounds. Subsequently, the molecular identification and phylogenetic construction of the isolated EA strain was confirmed as N. dassonvillei DMS 1 (MH900216). The liquid-liquid extraction of the compound demonstrated 24- and 26-mm zones of inhibition against A. baumannii and K. pneumoniae, respectively. Furthermore, the purified crude compound demonstrated 92% and 94% cell death against A. baumannii and K. pneumoniae, respectively, at a minimum inhibitory concentration of 500 μg/mL. Overall, the present study demonstrated the antibacterial properties of the EA N. dassonvillei DMS 1 (MH900216) isolated from Sea grasses and their importance as alternative sources for discovering new antibiotics to inhibit MDR bacteria.