Although Carnobacterium maltaromaticum has been used as a probiotic in fish, it was reported to cause disease for the first time in Korea. The objective of this study was to understand the differences between pathogenic and non‐pathogenic strains. Pathogenicity was tested by challenging rainbow trout with C. maltaromaticum ATCC35586 and 18ISCm isolated from diseased fish, and DSM20342 isolated from a dairy product. We also compared 24 genomes of C. maltaromaticum strains plus the genome of our isolate 18ISCm sequenced in this study. Only the strains from diseased fish caused high mortality with severe histopathological changes. Although all strains shared more than 90% of Ko_id, wecC and xtmA were found only in strains from diseased fish. Interestingly, only strains from diseased fish harboured two wecC paralogs involved in the production of D‐mannosaminuronic acid which is a major component of a well‐known virulence factor, teichuronic acid. Two wecC paralogs of 18ISCm were increased when they were co‐cultured with trout blood cells, suggesting that wecC genes might play a role in virulence. The results of this study show that strains isolated from diseased fish are different from strains derived from food in terms of pathogenicity to fish and the presence of virulence‐related genes.

中文翻译：

---

带有重要毒力相关基因的患病鱼的麦芽食肉杆菌（Carnobacterium maltaromaticum）全基因组比较。

尽管麦芽糖食肉杆菌已被用作鱼类中的益生菌，但据报道它在韩国首次引起疾病。这项研究的目的是了解致病菌株和非致病菌株之间的差异。通过用从患病鱼类中分离出的麦芽糖梭菌ATCC35586和18ISCm以及从乳制品中分离出的DSM20342 ，挑战虹鳟来测试致病性。我们还比较了麦芽糖梭菌菌株的24个基因组，加上本研究中测序的分离株18ISCm的基因组。只有患病鱼类的品系才导致高死亡率，并伴有严重的组织病理学改变。尽管所有菌株都共享超过90％的Ko_id，wecC和xtmA仅在患病鱼类的品系中发现。有趣的是，只有来自患病鱼类的品系才含有两个涉及D-甘露糖醛酸生产的wecC旁系同源物，D-甘露糖醛酸是众所周知的毒力因子teurhuronic acid的主要成分。当它们与鳟鱼血细胞共培养时，两个18cSCm的wecC旁系同源物增加，表明wecC基因可能在毒力中起作用。这项研究的结果表明，从患病鱼中分离出的菌株与从食物中分离出的菌株在对鱼类的致病性和与毒力相关的基因方面均存在差异。