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

UNLABELLED: Marine 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 (12.8%) 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. 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.

Partial characterization of an exopolysaccharide secreted by a marine bacterium, Vibrio neocaledonicus sp. nov., from New Caledonia.

AIMS: Exopolysaccharides (EPS) are industrially valuable molecules with numerous useful properties. This study describes the techniques used for the identification of a novel Vibrio bacterium and preliminary characterization of its EPS. METHODS AND RESULTS: Bioprospection in marine intertidal areas of New Caledonia followed by screening for EPS producing brought to selection of the isolate NC470. Phylogenetic analysis (biochemical tests, gene sequencing and DNA-DNA relatedness) permitted to identify NC470 as a new member of the Vibrio genus. The EPS was produced in batch fermentation, purified using the ultrafiltration process and analysed by colorimetry, Fourier Transform Infrared spectroscopy, gas chromatography, Nuclear Magnetic Resonance and HPLC-size exclusion chromatography. This EPS exhibits a high N-acetyl-hexosamines and uronic acid content with a low amount of neutral sugar. The molecular mass was 672 × 10(3)  Da. These data are relevant for possible technological exploitation. CONCLUSIONS: We propose the name Vibrio neocaledonicus sp. nov for this isolate NC470, producing an EPS with an unusual sugar composition. Comparison with other known polymers permitted to select applications for this polymer. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to evaluate the marine biodiversity of New Caledonia. It also highlights the biotechnological potential of New Caledonia marine bacteria.

HLA class II antibodies in transfusion-related acute lung injury (TRALI). A case report.

TRALI, a serious complication of blood transfusion, is underdiagnosed. Anti-granulocyte and anti-HLA class I molecules in donors or recipients and very recently, lipids in stored blood as well as anti-HLA class II have been associated with the syndrome. We present a TRALI case which occurred in a 56 year old woman after plasma transfusion. HLA class II antibodies were identified in the donor and were correlated with the recipients' HLA antigens. The presence of HLA class II antibodies without anti-HLA class I has been reported in very few cases and may facilitate the understanding of the pathogenesis of the syndrome.