Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (Grupo SEGABALBP) Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, 28040, Spain.
BMC Microbiol. 2013 Jan 24;13:15. doi: 10.1186/1471-2180-13-15.
The microorganisms intended for use as probiotics in aquaculture should exert antimicrobial activity and be regarded as safe not only for the aquatic hosts but also for their surrounding environments and humans. The objective of this work was to investigate the antimicrobial/bacteriocin activity against fish pathogens, the antibiotic susceptibility, and the prevalence of virulence factors and detrimental enzymatic activities in 99 Lactic Acid Bacteria (LAB) (59 enterococci and 40 non-enterococci) isolated from aquatic animals regarded as human food.
These LAB displayed a broad antimicrobial/bacteriocin activity against the main Gram-positive and Gram-negative fish pathogens. However, particular safety concerns based on antibiotic resistance and virulence factors were identified in the genus Enterococcus (86%) (Enterococcus faecalis, 100%; E. faecium, 79%). Antibiotic resistance was also found in the genera Weissella (60%), Pediococcus (44%), Lactobacillus (33%), but not in leuconostocs and lactococci. Antibiotic resistance genes were found in 7.5% of the non-enterococci, including the genera Pediococcus (12.5%) and Weissella (6.7%). One strain of both Pediococcus pentosaceus and Weissella cibaria carried the erythromycin resistance gene mef(A/E), and another two P. pentosaceus strains harboured lnu(A) conferring resistance to lincosamides. Gelatinase activity was found in E. faecalis and E. faecium (71 and 11%, respectively), while a low number of E. faecalis (5%) and none E. faecium exerted hemolytic activity. None enterococci and non-enterococci showed bile deconjugation and mucin degradation abilities, or other detrimental enzymatic activities.
To our knowledge, this is the first description of mef(A/E) in the genera Pediococcus and Weissella, and lnu(A) in the genus Pediococcus. The in vitro subtractive screening presented in this work constitutes a valuable strategy for the large-scale preliminary selection of putatively safe LAB intended for use as probiotics in aquaculture.
水产养殖中用作益生菌的微生物不仅应对水产宿主安全，而且应对其周围环境和人类安全，应具有抗菌活性和被视为安全。本工作的目的是调查 99 株从被视为人类食物的水生动物中分离的乳酸菌（LAB）（59 株肠球菌和 40 株非肠球菌）对鱼类病原体的抗菌/细菌素活性、抗生素敏感性以及毒力因子和有害酶活性的流行情况。
这些 LAB 对主要革兰氏阳性和革兰氏阴性鱼类病原体表现出广泛的抗菌/细菌素活性。然而，在肠球菌属（86%）（粪肠球菌，100%；屎肠球菌，79%）中发现了基于抗生素耐药性和毒力因子的特殊安全问题。魏斯氏菌属（60%）、戊糖片球菌属（44%）、乳杆菌属（33%）也存在抗生素耐药性，但乳球菌属和肠球菌属没有。在 7.5%的非肠球菌中发现了抗生素耐药基因，包括戊糖片球菌属（12.5%）和魏斯氏菌属（6.7%）。一株戊糖片球菌和一株魏斯氏菌携带红霉素耐药基因 mef(A/E)，另外两株戊糖片球菌携带林可酰胺类耐药基因 lnu(A)。在粪肠球菌和屎肠球菌中分别发现了 71%和 11%的明胶酶活性，而粪肠球菌的数量较少（5%），屎肠球菌则没有溶血活性。没有肠球菌和非肠球菌表现出胆汁去结合和粘蛋白降解能力或其他有害的酶活性。
据我们所知，这是首次在戊糖片球菌属和魏斯氏菌属中描述了 mef(A/E)，在戊糖片球菌属中描述了 lnu(A)。本工作中进行的体外消减筛选为大规模初步筛选用于水产养殖的益生菌提供了一种有价值的策略。
