Faculdade de Ciências Farmacêuticas de Ribeirão Preto-Universidade de São Paulo, Av. do Café s/n, CEP 14040-903, Ribeirão Preto/SP, Brazil.
J Food Prot. 2012 Jun;75(6):1083-9. doi: 10.4315/0362-028X.JFP-11-523.
Lactobacillus sakei 1 is a food isolate that produces a heat-stable antimicrobial peptide (sakacin 1, a class IIa bacteriocin) inhibitory to the opportunistic pathogen Listeria monocytogenes. Bacterial isolates with antimicrobial activity may be useful for food biopreservation and also for developing probiotics. To evaluate the probiotic potential of L. sakei 1, it was tested for (i) in vitro gastric resistance (with synthetic gastric juice adjusted to pH 2.0, 2.5, or 3.0); (ii) survival and bacteriocin production in the presence of bile salts and commercial prebiotics (inulin and oligofructose); (iii) adhesion to Caco-2 cells; and (iv) effect on the adhesion of L. monocytogenes to Caco-2 cells and invasion of these cells by the organism. The results showed that L. sakei 1 survival in gastric environment varied according to pH, with the maximum survival achieved at pH 3.0, despite a 4-log reduction of the population after 3 h. Regarding the bile salt tolerance and influence of prebiotics, it was observed that L. sakei 1 survival rates were similar (P > 0.05) for all de Man Rogosa Sharpe (MRS) broth formulations when tests were done after 4 h of incubation. However, after incubation for 24 h, the survival of L. sakei 1 in MRS broth was reduced by 1.8 log (P < 0.001), when glucose was replaced by either inulin or oligofructose (without Oxgall). L. sakei 1 was unable to deconjugate bile salts, and there was a significant decrease (1.4 log) of the L. sakei 1 population in regular MRS broth plus Oxgall (P < 0.05). In spite of this, tolerance levels of L. sakei 1 to bile salts were similar in regular MRS broth and in MRS broth with oligofructose. Lower bacteriocin production was observed in MRS broth when inulin (3,200 AU/ml) or oligofructose (2,400 AU/ml) was used instead of glucose (6,400 AU/ml). L. sakei 1 adhered to Caco-2 cells, and its cell-free pH-neutralized supernatant containing sakacin 1 led to a significant reduction of in vitro listerial invasion of human intestinal Caco-2 cells.
清酒乳杆菌 1 是一种食品分离株，它能产生一种耐热的抗菌肽（萨卡辛 1，一种 IIa 类细菌素），对机会性病原体李斯特菌具有抑制作用。具有抗菌活性的细菌分离株可用于食品生物保鲜，也可用于开发益生菌。为了评估清酒乳杆菌 1 的益生菌潜力，对其进行了以下测试：（i）体外胃抵抗性（用 pH 值为 2.0、2.5 或 3.0 的人工胃液进行调整）；（ii）在胆汁盐和商业益生元（菊粉和低聚果糖）存在下的存活和细菌素产生；（iii）对 Caco-2 细胞的粘附性；（iv）对李斯特菌与 Caco-2 细胞的粘附和该菌对这些细胞的侵袭的影响。结果表明，清酒乳杆菌 1 在胃环境中的存活率随 pH 值而变化，在 pH 值为 3.0 时达到最大值，尽管在 3 小时后种群减少了 4 个对数。关于胆汁盐耐受性和益生元的影响，观察到当在孵育 4 小时后进行测试时，清酒乳杆菌 1 在所有 de Man Rogosa Sharpe（MRS）肉汤配方中的存活率相似（P > 0.05）。然而，在孵育 24 小时后，当葡萄糖被菊粉或低聚果糖（无牛胆盐）取代时，清酒乳杆菌 1 在 MRS 肉汤中的存活率降低了 1.8 个对数（P < 0.001）。清酒乳杆菌 1 不能去结合胆汁盐，并且在常规 MRS 肉汤加 Oxgall 中，清酒乳杆菌 1 的种群数量显著减少（1.4 个对数）（P < 0.05）。尽管如此，清酒乳杆菌 1 对胆汁盐的耐受水平在常规 MRS 肉汤和含有低聚果糖的 MRS 肉汤中相似。当使用菊粉（3200 AU/ml）或低聚果糖（2400 AU/ml）代替葡萄糖（6400 AU/ml）时，在 MRS 肉汤中观察到较低的细菌素产生。清酒乳杆菌 1 能附着在 Caco-2 细胞上，其无细胞 pH 中和上清液中含有萨卡辛 1，可显著降低李斯特菌对体外人肠道 Caco-2 细胞的侵袭。
