Isolation and Characterization of Filterable Marine Bacteria

Abstract

Anderson , J. I. W. (Northeast Shellfish Sanitation Research Center, Narragansett, R.I.), and W. P. Heffernan . Isolation and characterization of filterable marine bacteria. J. Bacteriol 90: 1713–1718. 1965.—By a process of double filtration of seawater, first through a membrane filter with a pore diameter of 0.45 μ and then through a membrane filter with a pore diameter of 0.22 μ, it was possible to isolate on the surface of the latter membrane a group of marine organisms not usually encountered by conventional techniques of pour plates or one-stage filtration. Many of the isolates could not be identified, but the largest single group belonged to the genus Spirillum ; other isolates were placed in the genera Leucothrix, Flavobacterium, Cytophaga , and Vibrio . A group of four organisms which was not identified was characterized by the formation of large, club-shaped cells, 20 to 30 μ long. Of the 25 strains studied in detail, 22 required seawater for growth and 8 retained their filterable property after cultivation. No filterable bacteria were isolated from terrestrial samples.