用于特异性鉴定益生菌菌株亚种DSM 15954和Bi-07™的锁核酸水解探针
Locked Nucleic Acid Hydrolysis Probes for the Specific Identification of Probiotic Strains subsp. DSM 15954 and Bi-07™.
作者信息
Shehata Hanan R, Kiefer Anthony, Morovic Wesley, Newmaster Steven G
机构信息
Natural Health Product Research Alliance, College of Biological Science, University of Guelph, Guelph, ON, Canada.
Department of Microbiology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
出版信息
Front Microbiol. 2021 Dec 23;12:801795. doi: 10.3389/fmicb.2021.801795. eCollection 2021.
Probiotic health benefits are now well-recognized to be strain specific. Probiotic strain characterization and identification is thus important in clinical research and in the probiotic industry. This is becoming especially important with reports of probiotic products failing to meet the declared strain content, potentially compromising their efficacy. Availability of reliable identification methods is essential for strain authentication during discovery, evaluation and commercialization of a probiotic strain. This study aims to develop identification methods for strains subsp. DSM 15954 and Bi-07 (Bi-07™) based on real-time PCR, targeting single nucleotide polymorphisms (SNPs). The SNPs were targeted by PCR assays with locked nucleic acid (LNA) probes, which is a novel application in probiotic identification. The assays were then validated following the guidelines for validating qualitative real-time PCR assays. Each assay was evaluated for specificity against 22 non-target strains including closely related subsp. strains and were found to achieve 100% true positive and 0% false positive rates. To determine reaction sensitivity and efficiency, three standard curves were established for each strain. Reaction efficiency values were 86, 91, and 90% (R square values > 0.99), and 87, 84, and 86% (R square values > 0.98) for subsp. DSM 15954 and Bi-07 assays, respectively. The limit of detection (LOD) was 5.0 picograms and 0.5 picograms of DNA for DSM 15954 and Bi-07 assays, respectively. Each assay was evaluated for accuracy using five samples tested at three different DNA concentrations and both assays proved to be highly repeatable and reproducible. Standard deviation of Cq values between two replicates was always below 1.38 and below 1.68 for DSM 15954 and Bi-07 assays, respectively. The assays proved to be applicable to mono-strain and multi-strain samples as well as for samples in various matrices of foods or dietary supplement ingredients. Overall, the methods demonstrated high specificity, sensitivity, efficiency and precision and broad applicability to sample, matrix and machine types. These methods facilitate strain level identification of the highly monophyletic strains subsp. DSM 15954 and Bi-07 to ensure probiotic efficacy and provide a strategy to identify other closely related probiotics organisms.
益生菌的健康益处现在已被充分认识到具有菌株特异性。因此,益生菌菌株的表征和鉴定在临床研究和益生菌产业中都很重要。随着有报道称益生菌产品未能达到宣称的菌株含量,可能会影响其功效,这一点变得尤为重要。可靠的鉴定方法对于益生菌菌株的发现、评估和商业化过程中的菌株鉴定至关重要。本研究旨在基于实时荧光定量PCR(real-time PCR)开发针对嗜酸乳杆菌(Lactobacillus acidophilus)亚种DSM 15954和嗜热链球菌(Streptococcus thermophilus)Bi-07(Bi-07™)菌株的鉴定方法,以单核苷酸多态性(SNPs)为靶点。这些单核苷酸多态性通过带有锁核酸(LNA)探针的PCR检测法进行靶向,这在益生菌鉴定中是一种新的应用。然后按照定性实时荧光定量PCR检测法的验证指南对这些检测法进行验证。对每种检测法针对包括密切相关的嗜酸乳杆菌亚种菌株在内的22种非目标菌株进行特异性评估,发现其真阳性率达到100%,假阳性率为0%。为了确定反应灵敏度和效率,针对每种菌株建立了三条标准曲线。嗜酸乳杆菌亚种DSM 15954检测法和嗜热链球菌Bi-07检测法的反应效率值分别为86%、91%和90%(决定系数R平方值>0.99),以及87%、84%和86%(决定系数R平方值>0.98)。嗜酸乳杆菌亚种DSM 15954检测法和嗜热链球菌Bi-07检测法的检测限分别为5.0皮克和0.5皮克DNA。使用在三种不同DNA浓度下测试的五个样本对每种检测法的准确性进行评估,结果表明两种检测法都具有高度的重复性和再现性。对于嗜酸乳杆菌亚种DSM 15954检测法和嗜热链球菌Bi-07检测法,两次重复之间的Cq值标准偏差分别始终低于1.38和1.68。这些检测法被证明适用于单菌株和多菌株样本,以及食品或膳食补充剂成分的各种基质中的样本。总体而言,这些方法具有高特异性、灵敏度、效率和精密度,并且对样本、基质和仪器类型具有广泛的适用性。这些方法有助于对高度单系的嗜酸乳杆菌亚种DSM 15954和嗜热链球菌Bi-07菌株进行菌株水平鉴定,以确保益生菌的功效,并为鉴定其他密切相关的益生菌生物提供了一种策略。