Yang Zhenzhu, Ni Ling, Tian Wei, Chi Hai
East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China.
Microorganisms. 2023 Mar 27;11(4):849. doi: 10.3390/microorganisms11040849.
In the current study, we screened 46 isolates of lactic acid bacteria (LAB) derived from goat milk for bacteriocin producers that can inhibit common foodborne pathogens (, , and ). The following three strains that showed antimicrobial activity against all indicators were identified: DH9003 and DH9012, and DH9011. Their antimicrobial products exhibited typical bacteriocin characteristics, such as heat stability and proteinase nature. The bacteriostatic activity of concentrated bacteriocins produced by these LAB was observed at low concentrations (half-minimum inhibitory concentration [MIC50] and 4MIC50), whereas complete inhibition activity against was detected at high concentrations (16MIC50) of the two strains (DH9003 and DH9012). Furthermore, the probiotic potentials of the three strains were investigated and described. The results revealed that none of the strains had hemolytic activity, whereas all: were sensitive to ampicillin (50 mg/mL) and streptomycin sulfate (100 mg/mL); were resistant to bile, artificial simulated intestinal tract, and gastric juice at different pH levels (2.5, 3.0, 3.5); and had β-galactosidase activity. Furthermore, all strains exhibited an auto-aggregating phenotype, with self-aggregation ranging from 30% to 55%. DH9003 and DH9012 co-aggregated well with and (52.6% and 63.2%, 68.5% and 57.6%, respectively), whereas DH9011 co-aggregated poorly with (15.6%) and did not co-aggregate with Escherichia coli. Furthermore, our results showed that all three isolates exhibited strong antibacterial activity, tolerance to bile and simulated gastrointestinal environments, adhesion capability, and safety. Finally, DH9003 was selected and used for gavage in rats. By observing the pathological characteristics of rat intestinal and liver tissue sections, DH9003 showed no harmful effects on the intestine and liver of rats, but rather resulted in a denser and longer intestinal mucosa, as well as improving the intestinal mucosa of rats. Considering their substantial prospective applications, we concluded that these three isolates are potential probiotic candidates.
在本研究中，我们筛选了46株源自山羊奶的乳酸菌（LAB），以寻找能够抑制常见食源性病原体（、和）的细菌素产生菌。鉴定出以下三株对所有指标均表现出抗菌活性的菌株：DH9003和DH9012，以及DH9011。它们的抗菌产物表现出典型的细菌素特征，如热稳定性和蛋白酶性质。这些乳酸菌产生的浓缩细菌素在低浓度（半数最小抑菌浓度[MIC50]和4MIC50）下观察到抑菌活性，而在两株菌（DH9003和DH9012）的高浓度（16MIC50）下检测到对的完全抑制活性。此外，对这三株菌的益生菌潜力进行了研究和描述。结果显示，所有菌株均无溶血活性，而所有菌株：对氨苄青霉素（50 mg/mL）和硫酸链霉素（100 mg/mL）敏感；在不同pH水平（2.5、3.0、3.5）下对胆汁、人工模拟肠道和胃液具有抗性；并且具有β-半乳糖苷酶活性。此外，所有菌株均表现出自动聚集表型，自聚集率在30%至55%之间。DH9003和DH9012与和的共聚集性良好（分别为52.6%和63.2%，68.5%和57.6%），而DH9011与的共聚集性较差（15.6%），且不与大肠杆菌共聚集。此外，我们的结果表明，所有三株分离株均表现出较强的抗菌活性、对胆汁和模拟胃肠道环境的耐受性、黏附能力和安全性。最后，选择DH9003用于大鼠灌胃。通过观察大鼠肠道和肝脏组织切片的病理特征，DH9003对大鼠的肠道和肝脏没有有害影响，反而导致肠道黏膜更致密、更长，同时改善了大鼠的肠道黏膜。考虑到它们具有大量潜在的应用前景，我们得出结论，这三株分离株是潜在的益生菌候选菌株。
