Microbiology and Immunology Department, Faculty of Pharmacy, Beni-Suef University, Salah Salem Street, Beni Suef, 62511, Egypt.
Department of Chemistry, Biotechnology and Food Science, Laboratory of Microbial Gene Technology and Food Microbiology, Norwegian University of Life Sciences, Ås, Norway.
Sci Rep. 2021 Feb 15;11(1):3795. doi: 10.1038/s41598-021-83357-z.
Nosocomial infections caused by enterococci are an ongoing global threat. Thus, finding therapeutic agents for the treatment of such infections are crucial. Some Enterococcus faecalis strains are able to produce antimicrobial peptides called bacteriocins. We analyzed 65 E. faecalis isolates from 43 food samples and 22 clinical samples in Egypt for 17 common bacteriocin-encoding genes of Enterococcus spp. These genes were absent in 11 isolates that showed antimicrobial activity putatively due to bacteriocins (three from food, including isolate OS13, and eight from clinical isolates). The food-isolated E. faecalis OS13 produced bacteriocin-like inhibitory substances (BLIS) named enterocin OS13, which comprised two peptides (enterocin OS13α OS13β) that inhibited the growth of antibiotic-resistant nosocomial E. faecalis and E. faecium isolates. The molecular weights of enterocin OS13α and OS13β were determined as 8079 Da and 7859 Da, respectively, and both were heat-labile. Enterocin OS13α was sensitive to proteinase K, while enterocin OS13β was resistant. Characterization of E. faecalis OS13 isolate revealed that it belonged to sequence type 116. It was non-hemolytic, bile salt hydrolase-negative, gelatinase-positive, and sensitive to ampicillin, penicillin, vancomycin, erythromycin, kanamycin, and gentamicin. In conclusion, BLIS as enterocin OS13α and OS13β represent antimicrobial agents with activities against antibiotic-resistant enterococcal isolates.
肠球菌引起的医院感染是一个持续存在的全球性威胁。因此，寻找治疗此类感染的治疗剂至关重要。一些粪肠球菌菌株能够产生称为细菌素的抗菌肽。我们分析了来自埃及 43 个食品样本和 22 个临床样本的 65 株粪肠球菌，这些样本针对肠球菌 spp 的 17 个常见细菌素编码基因进行了分析。由于细菌素（包括来自食品的 3 株，包括 OS13 株，以及 8 株来自临床分离株），11 株具有抗菌活性的分离株中不存在这些基因。从食品中分离出的粪肠球菌 OS13 产生了类似细菌素的抑制物质（BLIS），命名为肠球菌 OS13，它由两种肽（肠球菌 OS13α 和 OS13β）组成，抑制了耐抗生素的医院获得性粪肠球菌和屎肠球菌分离株的生长。肠球菌 OS13α 和 OS13β 的分子量分别确定为 8079 Da 和 7859 Da，两者均不耐热。肠球菌 OS13α 对蛋白水解酶敏感，而肠球菌 OS13β 则具有抗性。粪肠球菌 OS13 分离株的特征表明它属于 116 型序列。它是非溶血的，胆汁盐水解酶阴性，明胶酶阳性，对氨苄西林、青霉素、万古霉素、红霉素、卡那霉素和庆大霉素敏感。总之，BLIS 作为肠球菌 OS13α 和 OS13β 代表了针对耐抗生素肠球菌分离株的抗菌剂。
