Marine Sediment Recovered Salinispora sp. Inhibits the Growth of Emerging Bacterial Pathogens and other Multi-Drug-Resistant Bacteria

Marine obligate actinobacteria produce a wide variety of secondary metabolites with biological activity, notably those with antibiotic activity urgently needed against multi-drug-resistant bacteria. Seventy-five marine actinobacteria were isolated from a marine sediment sample collected in Punta Arena de La Ventana, Baja California Sur, Mexico. The 16S rRNA gene identification, Multi Locus Sequence Analysis, and the marine salt requirement for growth assigned seventy-one isolates as members of the genus Salinispora, grouped apart but related to the main Salinispora arenicola species clade. The ability of salinisporae to inhibit bacterial growth of Staphylococcus epidermidis, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacer baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was evaluated by cross-streaking plate and supernatant inhibition tests. Ten supernatants inhibited the growth of eight strains of S. epidermidis from patients suffering from ocular infections, two out of the eight showed growth inhibition on ten S. epidermidis strains from prosthetic joint infections. Also, it inhibited the growth of the remaining six multi-drug-resistant bacteria tested. These results showed that some Salinispora strains could produce antibacterial compounds to combat bacteria of clinical importance and prove that studying different geographical sites uncovers untapped microorganisms with metabolic potential.