Song Dingka, Shuai Jing, Wang Yun, Yang Zhaoying, Dai Yuyang, Liu Lijun, Chen Yijia, Jiang Yinan, Du Mengze, Wang Hui
State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China.
College of Veterinary Medicine, Beijing University of Agriculture, 100096 Beijing, China.
Int J Biol Macromol. 2025 Jun;316(Pt 1):144674. doi: 10.1016/j.ijbiomac.2025.144674. Epub 2025 May 26.
Skin ulcer disease is a significant health and economic challenge in the growing turtle farming industry, primarily caused by pathogenic microorganisms found in aquatic environments. This study aimed to identify bacterial pathogens responsible for skin ulcer disease in farmed turtles and evaluate potential treatments. Bacterial strains were isolated from lesion tissues of diseased turtles, 16S rRNA gene sequencing revealed distinct microbial compositions between healthy and diseased turtles. Aeromonas hydrophilia was identified as the primary pathogen through enrichment evaluation, in vitro culturation and in vivo infection models. Antibiotic susceptibility testing showed high resistance rates of A. hydrophilia to a wide variety of antibiotics among the isolated bacteria, highlighting the necessity for alternative treatments. The therapeutic potential of Longan leaf polysaccharides (LLP) against A. hydrophilia were subsequently evaluated. In vitro experiments showed that LLP significantly inhibited the growth of A. hydrophilia. In addition, LLP treatment effectively reduced bacterial loads and alleviated disease symptoms in infected turtles in vivo. Transcriptomic analysis further revealed potential genes associated with antibacterial activity of LLP against A. hydrophilia. This study establishes A. hydrophilia as the leading cause of skin ulcer disease in farmed turtles and introduces LLP as a promising, natural therapeutic option to mitigate the disease.
皮肤溃疡病是日益发展的养龟业面临的重大健康和经济挑战，主要由水生环境中发现的致病微生物引起。本研究旨在鉴定养殖龟皮肤溃疡病的细菌病原体，并评估潜在的治疗方法。从患病龟的病变组织中分离出细菌菌株，16S rRNA基因测序揭示了健康龟和患病龟之间不同的微生物组成。通过富集评估、体外培养和体内感染模型，嗜水气单胞菌被确定为主要病原体。抗生素敏感性测试表明，在所分离的细菌中，嗜水气单胞菌对多种抗生素具有较高的耐药率，凸显了替代治疗的必要性。随后评估了龙眼叶多糖（LLP）对嗜水气单胞菌的治疗潜力。体外实验表明，LLP显著抑制嗜水气单胞菌的生长。此外，LLP治疗有效降低了感染龟体内的细菌载量并减轻了疾病症状。转录组分析进一步揭示了与LLP对嗜水气单胞菌抗菌活性相关的潜在基因。本研究确定嗜水气单胞菌是养殖龟皮肤溃疡病的主要病因，并引入LLP作为一种有前景的天然治疗选择来减轻该病。
