Díaz-Formoso Lara, Contente Diogo, Feito Javier, Orgaz Belén, Hernández Pablo E, Borrero Juan, Muñoz-Atienza Estefanía, Cintas Luis M
Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (Grupo SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos (Nutrición, Bromatología, Higiene y Seguridad Alimentaria) (SD-NUTRyCIAL), Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro, s/n, 28040 Madrid, Spain.
Sección Departamental de Farmacia Galénica y Tecnología Alimentaria (SD-FARMATEC), Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro, s/n, 28040 Madrid, Spain.
Antibiotics (Basel). 2025 May 6;14(5):469. doi: 10.3390/antibiotics14050469.
The overuse and misuse of antibiotics has contributed significatively to the growing problem of the emergence and spread of antibiotic resistance genes among bacteria, posing a serious global challenge to the treatment of bacterial infectious diseases. For these reasons, there is a current and growing interest in the development of effective alternative or complementary strategies to antibiotic therapy for the prevention of fish diseases, which are mainly based on the use of probiotics-in particular, those belonging to the Lactic Acid Bacteria (LAB) group. In this context, the aim of the present study was to characterise, evaluate the genetic diversity and assess the safety of candidate probiotic LAB strains for aquaculture isolated from faeces and intestines of European hakes (, L.) caught in the Northeast Atlantic Ocean (Ireland). The direct antimicrobial activity of the LAB isolates was tested by the Stab-On-Agar method against key ichthyopathogens. Subsequently, their taxonomic classification and genetic diversity were determined by sequencing and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), respectively. To ensure the in vitro safety of the LAB isolates, their biofilm-forming ability was assessed by a microtiter plate assay; their sensitivity to major antibiotics used in aquaculture, human and veterinary medicine by a broth microdilution method and their haemolytic and gelatinase activity by microbiological assays. All LAB isolates were biofilm producers and susceptible to chloramphenicol, oxytetracycline, flumequine and amoxicillin. A total of 30 isolates (85.7%) were resistant to at least one of the tested antibiotics. None of the 35 LAB isolates showed haemolytic or proteolytic activity. Among the isolated strains, five LAB strains exhibiting the highest antimicrobial activity against aquaculture-relevant ichthyopathogens, taxonomically identified as , and , were selected for further characterisation as potential probiotic candidates to promote sustainable aquaculture. To our knowledge, this is the first study to report that hake intestines and faeces represent viable ecological niches for the isolation of LAB strains with antimicrobial activity.
抗生素的过度使用和滥用在很大程度上导致了细菌中抗生素耐药基因出现和传播这一日益严重的问题，对细菌性传染病的治疗构成了严峻的全球挑战。出于这些原因，目前人们对开发有效的替代或补充策略以用于鱼类疾病预防的抗生素治疗的兴趣日益浓厚，这些策略主要基于益生菌的使用，特别是属于乳酸菌（LAB）组的益生菌。在此背景下，本研究的目的是对从东北大西洋（爱尔兰）捕获的欧洲无须鳕（Merluccius merluccius，L.）的粪便和肠道中分离出的水产养殖候选益生菌LAB菌株进行表征、评估其遗传多样性并评估其安全性。通过琼脂穿刺法测试LAB分离株对主要鱼类病原体的直接抗菌活性。随后，分别通过16S rRNA测序和肠杆菌重复基因间共识-PCR（ERIC-PCR）确定它们的分类学分类和遗传多样性。为确保LAB分离株的体外安全性，通过微量滴定板试验评估其生物膜形成能力；通过肉汤微量稀释法评估其对水产养殖、人类和兽医学中使用的主要抗生素的敏感性，并通过微生物学试验评估其溶血和明胶酶活性。所有LAB分离株均为生物膜产生菌，对氯霉素、土霉素、氟甲喹和阿莫西林敏感。共有30株分离株（85.7%）对至少一种测试抗生素耐药。35株LAB分离株均未表现出溶血或蛋白水解活性。在分离出的菌株中，选择了五株对与水产养殖相关的鱼类病原体具有最高抗菌活性的LAB菌株，它们在分类学上被鉴定为戊糖片球菌、植物乳杆菌和屎肠球菌，作为潜在的益生菌候选菌株进行进一步表征，以促进可持续水产养殖。据我们所知，这是第一项报道无须鳕肠道和粪便代表分离具有抗菌活性的LAB菌株的可行生态位的研究。
