PDF(Pubmed)
Abstract：
BACKGROUND: Streptococcus agalactiae, a Gram-positive bacterium, has emerged as an important pathogen for the aquaculture industry worldwide, due to its increased induced mortality rates in cultured fish. Developing interventions to cure or prevent infections based on natural alternatives to antibiotics has become a priority, however, given the absence of scientific evidence regarding their mode of action progress has been slow.
METHODS: In this study we aimed to investigate the effect of a mixture of organic acids (natural antimicrobials), AuraAqua (Aq), on the virulence of S. agalactiae using Tilapia gut primary epithelial cells and an in vitro Tilapia gut culture model. Our results show that Aq was able to reduce significantly, in vitro, the S. agalactiae levels of infection in Tilapia gut primary epithelial cells (TGP) when the MIC concentration of 0.125% was tested.
CONCLUSIONS: At bacterial level, Aq was able to downregulate bacterial capsule polysaccharide (CPS) gene expression, capC, resulting in a significant decrease in bacterial surface capsule production. The decrease in CPS production was also associated with a reduction in the pro-inflammatory IFNγ, IL1β, TNFα, SOD and CAT gene expression and H2O2 production in the presence of 0.125% Aq (P < 0.0001). The antimicrobial mixture also reduced the levels of S. agalactiae infection in an in vitro gut culture model and significantly reduced the IFNγ, IL1β, TNFα, SOD, CAT gene expression and H2O2 production in infected tissue. Moreover, genes involved in Tilapia resistance to S. agalactiae induced disease, MCP-8 and Duo-1, were also downregulated by Aq, as a consequence of reduced bacterial levels of infection.
CONCLUSIONS: Conclusively, our study shows that mixtures of organic acids can be considered as potential alternative treatments to antibiotics and prevent S. agalactiae infection and inflammation in the Tilapia fish digestive tract.
METHODS: In this study we aimed to investigate the effect of a mixture of organic acids (natural antimicrobials), AuraAqua (Aq), on the virulence of S. agalactiae using Tilapia gut primary epithelial cells and an in vitro Tilapia gut culture model. Our results show that Aq was able to reduce significantly, in vitro, the S. agalactiae levels of infection in Tilapia gut primary epithelial cells (TGP) when the MIC concentration of 0.125% was tested.
CONCLUSIONS: At bacterial level, Aq was able to downregulate bacterial capsule polysaccharide (CPS) gene expression, capC, resulting in a significant decrease in bacterial surface capsule production. The decrease in CPS production was also associated with a reduction in the pro-inflammatory IFNγ, IL1β, TNFα, SOD and CAT gene expression and H2O2 production in the presence of 0.125% Aq (P < 0.0001). The antimicrobial mixture also reduced the levels of S. agalactiae infection in an in vitro gut culture model and significantly reduced the IFNγ, IL1β, TNFα, SOD, CAT gene expression and H2O2 production in infected tissue. Moreover, genes involved in Tilapia resistance to S. agalactiae induced disease, MCP-8 and Duo-1, were also downregulated by Aq, as a consequence of reduced bacterial levels of infection.
CONCLUSIONS: Conclusively, our study shows that mixtures of organic acids can be considered as potential alternative treatments to antibiotics and prevent S. agalactiae infection and inflammation in the Tilapia fish digestive tract.
摘要：
背景：无乳链球菌，革兰氏阳性细菌，已成为全球水产养殖业的重要病原体，由于其在养殖鱼类中的诱导死亡率增加。开发基于抗生素的天然替代品的治疗或预防感染的干预措施已成为当务之急。然而,鉴于缺乏有关其行动方式的科学证据，进展缓慢。
方法：在这项研究中，我们旨在研究有机酸（天然抗菌剂）混合物的作用，AuraAqua(Aq),用罗非鱼肠道原代上皮细胞和体外罗非鱼肠道培养模型研究无乳链球菌的毒力。我们的结果表明，Aq能够显着降低，在体外，当MIC浓度为0.125％时，罗非鱼肠道原代上皮细胞（TGP）的无乳链球菌感染水平进行了测试。
结论：在细菌水平，Aq能够下调细菌荚膜多糖（CPS）基因表达，capc,导致细菌表面胶囊产量显着下降。CPS产生的减少也与促炎IFNγ的减少有关，IL1β,TNFα,在0.125%Aq存在下SOD和CAT基因表达和H2O2产生(P<0.0001)。抗微生物混合物还降低了体外肠道培养模型中无乳链球菌感染的水平，并显着降低了IFNγ，IL1β,TNFα,SOD,感染组织中CAT基因的表达和H2O2的产生。此外，与罗非鱼对无乳链球菌诱导疾病的抗性有关的基因，MCP-8和Duo-1也被Aq下调，作为降低细菌感染水平的结果。
结论：最后，我们的研究表明，有机酸的混合物可以被认为是抗生素的潜在替代疗法，并预防罗非鱼消化道的无乳链球菌感染和炎症。
方法：在这项研究中，我们旨在研究有机酸（天然抗菌剂）混合物的作用，AuraAqua(Aq),用罗非鱼肠道原代上皮细胞和体外罗非鱼肠道培养模型研究无乳链球菌的毒力。我们的结果表明，Aq能够显着降低，在体外，当MIC浓度为0.125％时，罗非鱼肠道原代上皮细胞（TGP）的无乳链球菌感染水平进行了测试。
结论：在细菌水平，Aq能够下调细菌荚膜多糖（CPS）基因表达，capc,导致细菌表面胶囊产量显着下降。CPS产生的减少也与促炎IFNγ的减少有关，IL1β,TNFα,在0.125%Aq存在下SOD和CAT基因表达和H2O2产生(P<0.0001)。抗微生物混合物还降低了体外肠道培养模型中无乳链球菌感染的水平，并显着降低了IFNγ，IL1β,TNFα,SOD,感染组织中CAT基因的表达和H2O2的产生。此外，与罗非鱼对无乳链球菌诱导疾病的抗性有关的基因，MCP-8和Duo-1也被Aq下调，作为降低细菌感染水平的结果。
结论：最后，我们的研究表明，有机酸的混合物可以被认为是抗生素的潜在替代疗法，并预防罗非鱼消化道的无乳链球菌感染和炎症。
