Three marine bacterial strains designated YLB-06^T, YLB-08^T and YLB-09 were isolated under high hydrostatic pressure from deep-sea sediment samples collected from the Southwest Indian Ocean. They were Gram-stain-negative, oxidase- and catalase-positive, facultative anaerobic and motile. In addition, the strains were capable of growing at 0–20 °C (optimum 4–10 °C) and 0.1–40 MPa (optimum 0.1 MPa), were psychrophiles and piezotolerant, and could use trimethylamine N-oxide (TMAO), DMSO, elemental sulfur and insoluble Fe (III) as terminal electron acceptors during anaerobic growth. Strain YLB-06^T could also use nitrate, and strains YLB-08^T and YLB-09 could use nitrite as a terminal electron acceptor. Phylogenetic tree analyses based on 16S rRNA gene sequences and 400 optimized universal marker sequences indicated that the strains belonged to the genus Shewanella. The 16S rRNA gene highest similarity, together with the estimated ANI and DDH values for these strains with their related type strains, were below the respective thresholds for species differentiation. The ANI and DDH values between YLB-08^T and YLB-09 were 99.9% and 91.8%, respectively, implying that they should belong to the same genospecies. The YLB-06^T genome had duplicated genes, and multiple movement modalities, attachment modalities, biofilm synthesis systems, intercellular interactions and a strong antioxidant system, which were all beneficial for survival in an extreme deep-sea environment. The G + C contents of strains YLB-06^T, YLB-08^T and YLB-09 were 45.1, 43.5 and 43.6 mol%, respectively. Based on polyphasic taxonomic properties, two novel psychropiezotolerant species are proposed, Shewanella psychropiezotolerans sp. nov. with YLB-06^T (=MCCC 1A12715^T = KCTC 62907^T) and S. eurypsychrophilus sp. nov with YLB-08^T (=MCCC 1A12718^T = KCTC 62909^T) as type strains.

在高静水压力下从西南印度洋收集的深海沉积物样品中分离出三种命名为 YLB-06 ^T、YLB-08 ^T和 YLB-09 的海洋细菌菌株。它们是革兰氏染色阴性、氧化酶和过氧化氢酶阳性、兼性厌氧和能动的。此外，菌株能够在 0–20 °C（最佳 4–10 °C）和 0.1–40 MPa（最佳 0.1 MPa）下生长，是嗜冷菌和耐压的，并且可以使用三甲胺 N-氧化物 (TMAO)， DMSO、元素硫和不溶性 Fe (III) 作为厌氧生长过程中的终端电子受体。菌株 YLB-06 ^T也可以使用硝酸盐，菌株 YLB-08 ^TYLB-09 可以使用亚硝酸盐作为末端电子受体。基于16S rRNA基因序列和400个优化通用标记序列的系统进化树分析表明，该菌株属于希瓦氏菌属。16S rRNA 基因的最高相似性，连同这些菌株与其相关类型菌株的估计 ANI 和 DDH 值，都低于各自的物种分化阈值。YLB-08 ^T和 YLB-09之间的 ANI 和 DDH 值分别为 99.9% 和 91.8%，表明它们应该属于相同的基因种。YLB-06 ^T基因组具有重复的基因，以及多种运动方式、附着方式、生物膜合成系统、细胞间相互作用和强大的抗氧化系统，这些都有益于在极端深海环境中的生存。菌株YLB-06 ^T、YLB-08 ^T和YLB-09的G+C含量分别为45.1、43.5和43.6 mol%。基于多相分类特性，提出了两种新的耐低温物种，Shewanella psychropiezotolerans sp。十一月 YLB-06 ^T (=MCCC 1A12715 ^T  = KCTC 62907 ^T ) 和S. eurypsychrophilus sp. 11 月与 YLB-08 ^T (=MCCC 1A12718 ^T  = KCTC 62909^T ) 作为类型菌株。