Sea bacteria can produce compounds that can replace existing antibiotics that, due to the development of bacterial resistance, are no longer effective in therapeutical treatments. That is the conclusion from a study carried out by the researchers Claudia Schinke, Thamires Martins, and Felix Reyes, from the Campinas State University; and Sonia Queiroz and Itamar Melo, from Embrapa Environment (Jaguariúna, SP), and published in January 2017 by the Journal of Natural Products. The scientists reviewed research on antibacterial compounds produced by sea-derived bacteria, conducted between 2010 and 2015, and concluded that they have the ability to produce metabolites of varied chemical structures with antibacterial activity. According to Claude Schinke, during the study period, more than 50 active compounds were isolated, of which about 69% were obtained of the Actinobacteria bacterial class. Many of those compounds were already known, such as etamycin A and nosiheptide, however, new experiments have shown that they have antibacterial activity that was previously undetected, explains the researcher, stressing the fact that known compounds are also an important source of antibacterials. The compounds reported in the period belong to 28 different chemical classes, of which 10 represent new classes of molecules. More than 30 of such new compounds were able to inhibit a several lineages of Gram-negative and Gram-positive bacteria. Some molecules presented highly selective antibacterial activities against Gram-positive bacteria in in vivo septicemia models and thus could become new drugs. Moreover, the effectiveness of the molecules proved to be comparable to first-line antibiotics. New action mechanisms were also detected, but not completely elucidated. Anthracimycin, kocurin, gageotetrins A−C and gageomacrolactins 1−3 are examples of molecules that offer promising properties. In addition, the study reported molecules pertaining to a new class of antibacterial compounds - virulence blockers, such as piericidin A1 and its derivative mer-A 2026B. Some microrganisms produced a mix of metabolites that share the same basic chemical structure, and the relationships between their structures and their activities are discussed in the text in the Journal of Natural Products. The study concludes that with the increasing development of oceanographic science and metabolome screening techniques, leading to the discovery of new species and metabolic profiles, new molecules are being discovered with potent inhibitory activity against current pathogens that have multiple resistance to antibiotics. The researcher stresses that efforts must be made to continuously explore the marine environment in search of new bioactive compounds for the development of new drugs. Translation: Mariana de Lima Medeiros