Characterization of Pseudomonas spp. from seawater of the southwest coast of Turkey

Abstract

In this work, 46 gram negative bacteria isolated from the seawater on the southwest coast of Turkey. These isolates were identified as 20 Pseudomonas spp., 15 Aeromonas spp., 8 Chryseomonas spp., 2 Burkholderia spp. and 1 Vibrio spp. by biochemical and conventional methods. And then study was continued for the 20 Pseudomonas isolates. Species identification of these isolates were made by means of API 20 NE. Enzymatic activities of these strains were determined by API ZYM. The strains were further characterized by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and 16S ribosomal DNA sequencing. According to the results obtained by phenotypic methods; the 20 isolates were identified as 6 Pseudomonas aeruginosa, 7 P.fluorescens, 3 P.putida, 2 P.stutzeri, 1 P.mendocina and 1 P.alcaligenes. The results of protein profiles and 16S rDNA sequence correlated well with phenotypic classification for P.aeruginosa, P.putida, P.stutzeri and P.mendocina strains. Good overall agreement between phenotypic and genotypic identification procedures was found for the 17 Pseudomonas spp. But discordance of identification between phenotypic methods and 16S rDNA sequence analysis was observed for two P. fluorescens (P 5-4 and P 9-2). Indeed these isolates were genotypically identified as P.putida. One strain (P 4-3), identified as, P.alcaligenes based on phenotypic characters, were identified as P.pseudoalcaligenes by 16S rDNA sequencing. These results indicate that the procedures for the identification of Pseudomonas spp. based on phenotypic characteristics should be additionally verified by the molecular methods to obtain results that are meaningful as well as accurate.