RESUMEN
Vibrio alginolyticus has acquired increasing importance because this microorganism may be pathogenic to aquatic animals and humans. It has been reported that some V. alginolyticus strains carry virulence genes derived from pathogenic V. cholerae and V. parahaemolyticus strains. In this work V. alginolyticus was isolated from oyster samples acquired from a food-market in Mexico City. Thirty isolates were identified as V. alginolitycus. Strains showed β-haemolysis and proteolytic activity and produced a capsule. Strains displayed swimming and swarming motility and 93.3% of them produced siderophores. Several genes encoding virulence factors were detected using PCR amplification. These included proA, wza, vopD, vopB, hcp, vasH and vgrG genes, which were present in all strains. Other genes had a variable representation: tdh (86.6%), lafA (96.6%), pvsA (62%) and pvuA (16%). The trh gene could not be amplified from any of the strains. The antimicrobial resistance profile revealed that more than 90% of the strains were resistant to beta-lactams antibiotics, 60% to cephalotin, 45% to amikacin, 16% to cephotaxime, and 10% to pefloxacin, while 100% were susceptible to ceftriaxone. The V. alginolyticus strains isolated from oysters showed multiple resistance to antibiotics and several virulence factors described in well-characterized pathogenic vibrios (AU)
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Asunto(s)
Vibrio alginolyticus/patogenicidad , Vibriosis/tratamiento farmacológico , Antibacterianos/uso terapéutico , Ostreidae/microbiología , Farmacorresistencia Bacteriana , Polisacáridos Bacterianos/inmunología , Factores de Virulencia/análisis , Pruebas de Sensibilidad Microbiana/estadística & datos numéricos , Moluscos/microbiología , Contaminación de AlimentosRESUMEN
Two new angucyclines, saccharothrixmicines A (2) and B (3), together with three known diketopiperazines 4-6 were isolated from the actinomycete Saccharothrix espanaensis An 113 associated with the marine mollusk Anadara broughtoni. Their structures were determined by HRESI-MS and 1D and 2D NMR. Compounds 2 and 3 differ in aglycone and glycosidic bond type. 2 is an alpha-L-6-deoxyaltrose-phenylglycoside of a benz[a]anthraquinone aglycone, while 3 is an O-glycoside of the same sugar linked to C-7 of the known angucyclinone (1). A saccharothrixmicine-containing fraction exhibited activity towards Candida albicans and Xanthomonas sp. pv. badrii whereas the diketopiperazines showed antibiotic activities against Vibrio alginolyticus and Vibrio parahaemolyticus.
Asunto(s)
Actinobacteria/química , Antraquinonas/aislamiento & purificación , Antibacterianos/aislamiento & purificación , Antifúngicos/aislamiento & purificación , Dicetopiperazinas/aislamiento & purificación , Moluscos/microbiología , Animales , Antraquinonas/química , Antraquinonas/farmacología , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Dicetopiperazinas/química , Dicetopiperazinas/farmacología , Pruebas de Sensibilidad Microbiana , Resonancia Magnética Nuclear Biomolecular , Rotación Óptica , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrofotometría Infrarroja , Espectrofotometría UltravioletaRESUMEN
A cellulolytic, dinitrogen-fixing bacterium isolated from the gill tissue of a wood-boring mollusc (shipworm) Lyrodus pedicellatus of the bivalve family Teredinidae and 58 additional strains with similar properties, isolated from gills of 24 bivalve species representing 9 of 14 genera of Teredinidae, are described. The cells are Gram-negative, rigid, rods (0.4-0.6 x 3-6 microm) that bear a single polar flagellum. All isolates are capable of chemoheterotrophic growth in a simple mineral medium supplemented with cellulose as a sole source of carbon and energy. Xylan, pectin, carboxymethylcellulose, cellobiose and a variety of sugars and organic acids also support growth. Growth requires addition of combined nitrogen when cultures are vigorously aerated, but all isolates fix dinitrogen under microaerobic conditions. The pH, temperature and salinity optima for growth were determined for six isolates and are approximately 8.5, 30-35 degrees C and 0.3 M NaCl respectively. The isolates are marine. In addition to NaCl, growth requires elevated concentrations of Ca2+ and Mg2+ that reflect the chemistry of seawater. The DNA G+C content ranged from 49 to 51 mol%. Four isolates were identical with respect to small-subunit rRNA sequence over 891 positions compared and fall within a unique clade in the gamma-subclass of the Proteobacteria. Based on morphological, physiological and phylogenetic characteristics and specific symbiotic association with teredinid bivalves, a new genus and species, Teredinibacter turnerae gen. nov., sp. nov., is proposed. The type strain is T7902(T) (= ATCC 39867(T) = DSM 15152(T)).