Ogaki Mayara Baptistucci, Rocha Katia Real, Terra MÁrcia Regina, Furlaneto MÁrcia Cristina, Maia Luciana Furlaneto
Department of Microbiology, Londrina State University, 86051-980 Londrina, Brazil.
Department of Food Microbiology, Federal Technological University of Paraná, 86036-370 Londrina, Brazil.
J Microbiol Biotechnol. 2016 Jun 28;26(6):1026-34. doi: 10.4014/jmb.1509.09020.
In the current study, a total of 135 enterococci strains from different sources were screened for the presence of the enterocin-encoding genes entA, entP, entB, entL50A, and entL50B. The enterocin genes were present at different frequencies, with entA occurring the most frequently, followed by entP and entB; entL50A and L50B were not detected. The occurrence of single enterocin genes was higher than the occurrence of multiple enterocin gene combinations. The 80 isolates that harbor at least one enterocin-encoding gene (denoted "Gene(+) strains") were screened for antimicrobial activity. A total of 82.5% of the Gene(+) strains inhibited at least one of the indicator strains, and the isolates harboring multiple enterocin-encoding genes inhibited a larger number of indicator strains than isolates harboring a single gene. The indicator strains that exhibited growth inhibition included Listeria innocua strain CLIP 12612 (ATCC BAA-680), Listeria monocytogenes strain CDC 4555, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 29213, S. aureus ATCC 6538, Salmonella enteritidis ATCC 13076, Salmonella typhimurium strain UK-1 (ATCC 68169), and Escherichia coli BAC 49LT ETEC. Inhibition due to either bacteriophage lysis or cytolysin activity was excluded. The growth inhibition of antilisterial Gene+ strains was further tested under different culture conditions. Among the culture media formulations, the MRS agar medium supplemented with 2% (w/v) yeast extract was the best solidified medium for enterocin production. Our findings extend the current knowledge of enterocin-producing enterococci, which may have potential applications as biopreservatives in the food industry due to their capability of controlling food spoilage pathogens.
在本研究中，对总共135株来自不同来源的肠球菌菌株进行筛选，以检测其是否存在编码肠球菌素的基因entA、entP、entB、entL50A和entL50B。肠球菌素基因出现的频率各不相同，其中entA出现的频率最高，其次是entP和entB；未检测到entL50A和L50B。单一肠球菌素基因的出现频率高于多种肠球菌素基因组合的出现频率。对80株携带至少一种编码肠球菌素基因的分离株（称为“基因阳性菌株”）进行抗菌活性筛选。总共82.5%的基因阳性菌株抑制了至少一种指示菌株，并且携带多种编码肠球菌素基因的分离株比携带单一基因的分离株抑制的指示菌株数量更多。表现出生长抑制的指示菌株包括无害李斯特菌菌株CLIP 12612（ATCC BAA - 680）、产单核细胞李斯特菌菌株CDC 4555、粪肠球菌ATCC 29212、金黄色葡萄球菌ATCC 25923、金黄色葡萄球菌ATCC 29213、金黄色葡萄球菌ATCC 6538、肠炎沙门氏菌ATCC 13076、鼠伤寒沙门氏菌菌株UK - 1（ATCC 68169）和大肠杆菌BAC 49LT ETEC。排除了由噬菌体裂解或溶细胞素活性导致的抑制作用。在不同培养条件下进一步测试了抗李斯特菌基因阳性菌株的生长抑制情况。在培养基配方中，添加2%（w/v）酵母提取物 的MRS琼脂培养基是用于生产肠球菌素的最佳固化培养基。我们的研究结果扩展了目前对产肠球菌素肠球菌的认识，由于它们具有控制食品腐败病原体的能力，这些肠球菌在食品工业中可能作为生物防腐剂具有潜在应用价值。
