Pedobacter aquae sp. nov., a multi-drug resistant bacterium isolated from fresh water

A novel bacterial strain designated CJ43^T was isolated from fresh water located in Gangwon-do, South Korea, displaying multi-drug resistance. The isolate was Gram-stain-negative, aerobic, orange-pigmented, and rod-shaped. Strain CJ43^T grew optimally at 30 °C and pH 7 on R2A agar in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain CJ43^T belonged to the genus Pedobacter in the family Sphingobacteriaceae and was most closely related to Pedobacter puniceum HX-22-1 ^T and P. glucosidilyticus 1-2 ^T (98.3 and 98.1% sequence similarity). The genome size of strain CJ43^T was 3.9 Mb in a single contig with DNA G + C content of 34.9%. The genome included 3144 predicted protein-coding genes, as well as 55 tRNA, 9 rRNA and 3 ncRNA genes. The genome also contained 128 putative antibiotic resistance genes, reflecting its phenotypes. The average nucleotide identity values between strain CJ43^T and two closely related strains P. puniceum HX-22-1 ^T and P. glucosidilyticus 1-2 ^T were 91.0 and 88.7%, respectively. In silico digital DNA-DNA hybridization results between strain CJ43^T and the related strains were 42.8 and 38.6%, respectively. The major fatty acids of strain CJ43^T were iso-C_15:0, iso-C_17:0 3-OH, and summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c). Strain CJ43^T contained phosphatidylethanolamine as the major polar lipid and menaquinone-7 as the sole respiratory quinone. Based on the polyphasic taxonomy data, strain CJ43^T represents a novel species of the genus Pedobacter, for which the name Pedobacter aquae sp. nov. is proposed with the type strain CJ43^T (= KACC 21350 ^T = JCM 33709 ^T).