A Systematic Approach to Identify and Characterize the Effectiveness and Safety of Novel Probiotic Strains to Control Foodborne Pathogens
A Systematic Approach to Identify and Characterize the Effectiveness and Safety of Novel Probiotic Strains to Control Foodborne Pathogens
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DOI：
10.3389/fmicb.2019.01108
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发表时间：
2019-05-17
影响因子：
5.2
通讯作者：
Nightingale, Kendra K.
中科院分区：
文献类型：
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作者：
Ayala, Diana I.;Cook, Peter W.;Nightingale, Kendra K.
对44株从牛粪和不同食物来源中分离的乳酸菌进行了益生特性筛选。所有菌株的抗菌活性进行了测试，通过良好的扩散试验和竞争性排除对蒙得维的亚沙门氏菌，大肠杆菌O 157：H7和李斯特菌菌株N1-002肉汤。38个LAB菌株对本研究中测试的至少一种病原体显示出拮抗作用。对L.当使用LAB过夜培养物时，单核细胞增多症的抑制区高达24 mm，当使用无细胞培养物时，抑制区高达21 mm。大肠大肠杆菌O 157：H7和沙门氏菌的最大抑制分别为12和11.5 mm。43株菌在肉汤上能使L.单核细胞增多症达9.06 log（10）CFU/ml，41株还原型E.大肠杆菌O 157：H7共接种24 h后，沙门氏菌的菌数下降至0.84 log（10）CFU/ml，其中32株菌的菌数下降至0.94 log（10）CFU/ml。进一步分析了在病原体中表现出最高抑制作用的28种LAB分离株，以确定其抗菌剂耐药性、粘附潜力和对Caco-2细胞的细胞毒性。所有供试LAB菌株均对氨苄青霉素、利奈唑胺和青霉素敏感。26个能够粘附于Caco-2细胞，5个被归类为具有> 40个细菌细胞/Caco-2细胞的高度粘附性。观察到候选LAB菌株的细胞毒性百分比较低，数值范围为-5%至8%。通过全基因组测序进行的基因型鉴定证实所有菌株均为LAB组的成员;肠球菌属是最常分离的属，有21株，其次是片球菌属，有4株，乳杆菌属，有3株。在这项研究中，一个系统的方法被用来改进新的乳酸菌菌株能够发挥拮抗作用，对重要的食源性病原体的鉴定。我们的研究结果表明，所选的一组LAB益生菌菌株可用作生物控制培养物，以抑制和/或减少L.单核细胞增多症、沙门氏菌和E. coli O 157：H7在不同基质和环境中的表达。
A total of 44 lactic acid bacteria (LAB) strains originally isolated from cattle feces and different food sources were screened for their potential probiotic features. The antimicrobial activity of all isolates was tested by well-diffusion assay and competitive exclusion on broth against Salmonella Montevideo, Escherichia coli O157:H7 and Listeria monocytogenes strain N1-002. Thirty-eight LAB strains showed antagonistic effect against at least one of the pathogens tested in this study. Improved inhibitory effect was observed against L. monocytogenes with zones of inhibition up to 24 mm when LAB overnight cultures were used, and up to 21 mm when cell-free filtrates were used. For E. coli O157:H7 and Salmonella maximum inhibitions of 12 and 11.5 mm were observed, respectively. On broth, 43 strains reduced L. monocytogenes up to 9.06 log(10) CFU/ml, 41 reduced E. coli O157:H7 up to 0.84 log(10) CFU/ml, and 32 reduced Salmonella up to 0.94 log(10) CFU/ml 24 h after co-inoculation. Twenty-eight LAB isolates that exhibited the highest inhibitory effect among pathogens were further analyzed to determine their antimicrobial resistance profile, adhesion potential, and cytotoxicity to Caco-2 cells. All LAB strains tested were susceptible to ampicillin, linezolid, and penicillin. Twenty-six were able to adhere to Caco-2 cells, five were classified as highly adhesive with > 40 bacterial cells/Caco-2 cells. Low cytotoxicity percentages were observed for the candidate LAB strains with values ranging from -5 to 8%. Genotypic identification by whole genome sequencing confirmed all as members of the LAB group; Enterococcus was the genus most frequently isolated with 21 isolates, followed by Pediococcus with 4, and Lactobacillus with 3. In this study, a systematic approach was used for the improved identification of novel LAB strains able to exert antagonistic effect against important foodborne pathogens. Our findings suggest that the selected panel of LAB probiotic strains can be used as biocontrol cultures to inhibit and/or reduce the growth of L. monocytogenes, Salmonella, and E. coli O157:H7 in different matrices, and environments.