Antibiotics from Deep-Sea Microorganisms: Current Discoveries and Perspectives

Abstract

The increasing emergence of new forms of multidrug resistance among human pathogenic bacteria, coupled with the consequent increase of infectious diseases, urgently requires the discovery and development of novel antimicrobial drugs with new modes of action. Most of the antibiotics currently available on the market were obtained from terrestrial organisms or derived semisynthetically from fermentation products. The isolation of microorganisms from previously unexplored habitats may lead to the discovery of lead structures with antibiotic activity. The deep-sea environment is a unique habitat, and deep-sea microorganisms, because of their adaptation to this extreme environment, have the potential to produce novel secondary metabolites with potent biological activities. This review covers novel antibiotics isolated from deep-sea microorganisms. The chemical classes of the compounds, their bioactivities, and the sources of organisms are outlined. Furthermore, the authors report recent advances in techniques and strategies for the exploitation of deep-sea microorganisms.

Keywords: antibiotics; deep-sea; extreme habitat; marine microorganisms; marine sediments.

Figure 1

Molecular structure of new cyclic peptides with antimicrobial activity isolated from deep-sea bacteria. Compound (1), marthiapeptide A, is a polythiazole cyclic peptide isolated from M. thermotolerans SCSIO 00652. Compound (2), desotamide B, is a cyclic hexapeptide isolated from Streptomyces scopuliridis SCSIO ZJ46. Compounds (3–5), marfomycins A, B, and E, are cyclic hepta-depsipeptides isolated from Streptomyces drozdowiczii SCSIO 10141.

Figure 2

Structures of new spirotetronate polyketides with antimicrobial activities isolated from deep-sea bacteria. Lobophorin F (6) was isolated from Streptomyces SCSIO 01127. Lobophorin H (7) was isolated from Streptomyces sp. 12A35S; Abyssomicin C (8) was isolated from Verrucosispora strain AB 18-032.

Figure 3

Structures of Marfuraquinocins A (9), C (10), and D (11) isolated from Streptomyces niveus SCSIO 3406.

Figure 4

Structure of caboxamycin (12).

Figure 5

Structures of Emerixanthones A–D (13–16).

Figure 6

Structure of Engyontiumone H (17).

Figure 7

Structures of Spiromastixones A–O (18–32).

Figure 8

Structures of Penicyclones A–E (33–37).