Pseudaeromonas paramecii sp. nov., isolated from the ciliate Paramecium caudatum and emendation of the genus Pseudaeromonas

A Gram-stain-negative, oxidase-negative and catalase-negative, motile, rod-shaped bacterial strain, designated PCS8 T , hosted by the ciliate Paramecium caudatum was investigated by using a polyphasic approach. Strain PCS8 T was observed to be able to grow at 12-44 °C (optimum, 36-37 °C), at pH 6.0-10.0 (optimum, 7.0) and in the presence of 0-3 % NaCl (optimum, 1-2 %). It could hydrolyse starch and aesculin and produce acid from d-sorbitol, myo -inositol, glycerol and l-rhamnose. The sequence similarity of the new isolate was 96.9 % with respect to Pseudaeromonas pectinilytica and 96.3 % with respect to Pseudaeromonas sharmana . Phylogenetically, strain PCS8 T falls within the cluster comprising the Pseudaeromonas species. The predominant cellular fatty acids of strain PCS8 T were C 16 : 0 (35.8 %), summed feature 3 (C 16 : 1 ω7 c and/or C 16 : 1 ω6 c ; 35.1 %) and summed feature 8 (C 18 : 1 ω7 c and/or C 18 : 1 ω6 c ; 10.8 %). This novel strain also contained various fatty acids that are not detected in other members of the genus Pseudaeromonas , such as C 16 : 0 3-OH, C 18 : 1 ω9 c and summed feature 5 (C 18 : 2 ω6,9 c and/or C 18 : 0 ante). Strain PCS8 T contained ubiquinone-8 as the sole respiratory quinone and phosphatidylethanolamine and phosphatidylglycerol as major polar lipids. The G+C content of the genomic DNA of the type strain was 66.5 mol%. Based on the distinct phenotypic, phylogenetic, chemotaxonomic and G+C content results, strain PCS8 T represents a currently undescribed species within the genus Pseudaeromonas in the family Aeromonadaceae , for which we suggest the name Pseudaeromonas paramecii sp. nov. with the type strain PCS8 T (=KCTC 62038 T =JCM 32226 T ). An emended description of the genus Pseudaeromonas is also provided.