Barbour Abdelahhad, Philip Koshy
Institute of Biological Sciences, Microbiology Division, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
PLoS One. 2014 Jun 18;9(6):e100541. doi: 10.1371/journal.pone.0100541. eCollection 2014.
Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production.
METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS). A new medium for maximum biomass production buffered with 2-(N-morpholino)ethanesulfonic acid (MES) was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10) and salivaricin G32 (by strain YU10) from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains.
The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for pharmaceuticals and probiotics from S. salivarius generating different lantibiotics. This is relevant for the clinical management of oral cavity and upper respiratory tract in the human population.
唾液乳杆菌素是由唾液链球菌产生的细菌素，其中一些菌株可具有显著的益生菌作用。从马来西亚受试者中分离出的唾液链球菌菌株表现出不同的抗菌活性、代谢谱、抗生素敏感性和羊毛硫抗生素产生情况。
方法/主要发现：在本研究中，我们报告了从马来西亚受试者中分离出的具有益生菌潜力的新型唾液链球菌菌株。对这些菌株的安全性评估包括它们的抗生素敏感性和代谢谱。使用Illumina的MiSeq系统对菌株NU10和YU10进行了基因组测序，结果表明不存在任何已知的链球菌毒力决定因素，这表明这些菌株作为益生菌后续使用是安全的。发现菌株NU10含有编码唾液乳杆菌素A和9的基因，而菌株YU10显示含有编码唾液乳杆菌素A3、G32、链菌素和slnA1类羊毛硫抗生素蛋白的基因。菌株GT2显示含有编码一种大型非羊毛硫抗生素细菌素（唾液乳杆菌素-MPS）的基因。开发了一种用2-（N-吗啉代）乙磺酸（MES）缓冲的用于最大生物量生产的新培养基，与其他商业培养基相比，其显示出更好的生物量积累。此外，我们从在该培养基中需氧生长的唾液链球菌细胞中提取并纯化了唾液乳杆菌素9（由菌株NU10产生）和唾液乳杆菌素G32（由菌株YU10产生）。除了产生细菌素外，唾液链球菌菌株还产生了左旋蔗糖酶，通过特定的电喷雾液相色谱-串联质谱法检测到，这表明所开发的菌株具有额外的健康益处。
当前研究确定了从健康马来西亚受试者中分离出的唾液链球菌菌株的细菌素、左旋蔗糖酶产生情况和基本安全特征，证明了它们作为益生菌使用的潜力。开发了一种新的细菌素生产培养基，具有扩大应用规模用于生产来自唾液链球菌产生不同羊毛硫抗生素的药物和益生菌的潜力。这与人群口腔和上呼吸道的临床管理相关。
