Shewanella subflava sp. nov., a novel multi-resistant bacterium, isolated from the estuary of the Fenhe River into the Yellow River

A aerobic, gram-negative, rod-shaped and polar-flagellum bacterial strain, designated as FYR11-62^T, was isolated from the estuary of the Fenhe River into the Yellow River in Shanxi Province, China. The isolate was able to grow at 4-37 °C (optimum, 25 °C), pH 5.5-9.5 (optimum, pH 7.5) and in the presence of 0-7.0% (w/v) NaCl (optimum, 1.0% NaCl). Phylogenetic analyses based on 16S rRNA genes and 1597 single-copy orthologous clusters indicated that strain FYR11-62^T affiliated with the genus Shewanella and shared the highest 16S rRNA gene sequence similarity to Shewanella aestuarii SC18^T (98.3%) and Shewanella gaetbuli TF-27^T (97.3%), respectively. The major fatty acids were summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), C_16:0 and iso-C_15:0. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The main quinones were Q-7 and Q-8. The genomic DNA G + C content was 41.6%. Gene annotation showed that strain FYR11-62^T possessed 30 antibiotic resistance genes, implying its multiple antidrug resistance. The average nucleotide identity and digital DNA-DNA hybridization values between strain FYR11-62^T and its closely related species were all below the thresholds for species delineation. The phylogenetic position together with the results of the analysis of morphological, physiological and genomic features support the classification of strain FYR11-62^T (= MCCC 1K07242^T = KCTC 92244^T) as a novel species of the genus Shewanella, for which the name Shewanella subflava sp. nov. is proposed.