Isolation and partial characterization of bacteria (Pseudoalteromonas sp.) with potential antibacterial activity from a marine costal environment from New Caledonia

Abstract

Significance and Impact of the Study: With the constant increasing of bacterial resistance against known antibiotics in worldwide public health, it is now necessary to find new sources of antimicrobials. Marine bacteria from New Caledonia were isolated, tested for antibacterial activity and characterized to find new active molecules against multidrug-resistant bacteria. This study illustrates the diversity of the marine ecosystem with potent new bacteria species. Also the potential of marine bacteria as a rich source of bioactive molecule, for example antibiotics, is highlighted. AbstractMarine bacteria are a rich source of bioactive metabolites. However, the microbial diversity of marine ecosystem still needs to be explored. The aim of this study was to isolate and characterize bacteria with antimicrobial activities from various marine coastal environment of New Caledonia. We obtained 493 marine isolates from various environments and samples of which 63 (12Á8%) presented an antibacterial activity against a panel of reference pathogenic strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis). Ten out of the most promising strains were cultured, fractionated and screened for antibacterial activity. Four of them (NC282, NC412, NC272 and NC120) showed at least an activity against reference and multidrug-resistant pathogenic strains and were found to belong to the genus Pseudoalteromonas, according to the 16S phylogenetic analysis. The NC282 strain does not belong to any described Pseudoalteromonas species and might be of interest for further chemical and biological characterization. These findings suggest that the identified strains may contribute to the discovery for new sources of antimicrobial substances to develop new therapies to treat infections caused by multidrug-resistant bacteria.

Screening for Bioflocculant-Producing Bacteria from the Marine Environment of Sodwana Bay, South Africa

“…was another bacterium identified as a producer of bioflocculant from this study; it is a rod-shaped, gramnegative bacteria. It is interesting to note, that Dufourcq et al, (2013), also isolated Pseudoalteromonas sp. from a marine coastal environment and found them to be a rich source of bioactive compounds.…”

Antagonistic activity of marine bacterial isolates on common human pathogenic bacteria

“…A total of six strains isolated from Arabian Sea of Pakistan showed antibacterial activity against Aeromonas punctata, Kokuria marina, Rothia marina, Vibrio cholerae, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Staphylococcus aureus and Proteus vulgaris [13] . Members of Firmicutes, Gamma proteobacteria, and Actinobacteria associated with the Red sea soft coral S. glaucum show a broad spectrum of antimicrobial activity and could be of great potential in producing novel antimicrobial agents [11] . Seawaters typically contains 107 viruses, 106 bacteria, 103 fungi, and 103 microalgae/ml, given that marine invertebrates and their symbionts are continuously exposed to a broad array of potentially deleterious microorganisms, it is reasonable that the production of bioactive secondary metabolites could act as fundamental mechanism of antimicrobial defense [14] .…”

“…Marine microorganisms are currently of considerable interest as a new and promising source of biologically active compounds. They produce a variety of metabolites, some of which can be used for drug development [11] . Many of the reports on antimicrobial activity of extracts of marine organisms and the subsequent purified antibiotics isolated from these organisms were tested against human pathogens as potential novel clinically useful drugs.…”

Marine Natural Products from New Caledonia—A Review

“…Along the west coast of New Caledonia, 205 environmental samples were collected on a variety of surfaces (sediments, intertidal rocks, invertebrates, plants, fish and biofilms found on organic substrates). This sampling led to the isolation of 493 marine bacteria [ 167 , 168 ]. Studies were at first performed to assess their ability to produce exopolysaccharides (EPSs).…”

“…Preliminary experiments conducted on these EPSs have shown high metal-binding capacity [ 167 ]. Further studies have shown that four other strains (NC282, NC412, NC272 and NC120), which belong to the genus Pseudoalteromonas , have antibacterial potential against reference and multidrug-resistant pathogen strains such as Staphylococcus aureus , Pseudomonas aeruginosa , Escherichia coli and Enterococcus faecalis [ 168 ].…”