PATHOGENIC POTENTIAL OF LACTOBACILLI
PATHOGENIC POTENTIAL OF LACTOBACILLI
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DOI：
10.1016/0168-1605(94)90117-1
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发表时间：
1994-12-01
影响因子：
5.4
通讯作者：
KNOX, KW
中科院分区：
文献类型：
--
作者：
HARTY, DWS;OAKEY, HJ;KNOX, KW
乳酸杆菌通常被认为是人类微生物生态学中的有益参与者，并且正在进行大量研究以了解乳酸杆菌作为人类和动物饮食中的添加剂的使用效果。然而，乳酸杆菌也引起一些人类疾病（例如龋齿、风湿性血管疾病、败血症和感染性心内膜炎（IE）），并且最近被确定为老年人和免疫功能低下患者（特别是那些接受广谱抗生素治疗的患者）的潜在新兴病原体。因此，乳酸杆菌中潜在致病性状的鉴定将有助于将该生物体用于益生菌目的。聚集人血小板的能力被认为是IE进展中的可能致病性状。比较了L.结果表明，5/5的IE株和8/16的实验室株可使血小板聚集。对于L.副干酪亚种副干酪菌菌株的数量分别为2/5和2/9。然而，两个菌株，非聚集性菌株的形态突变体，这已经通过大鼠传代后重新分离，发现聚集血小板。IE菌株经广泛传代培养后，聚集功能未丧失。14株其它5种乳酸杆菌中有11株也发生了聚集现象，即嗜酸乳杆菌、发酵乳酸杆菌、口腔乳酸杆菌、植物乳酸杆菌和唾液乳酸杆菌，每种乳酸杆菌都有代表性，表明该特性在该属中并不罕见。鼠李糖乳杆菌L.副干酪亚种paracasei和七种其它乳杆菌属物种已经表明，当pH从7.0降低到5.0时，乳杆菌对纤连蛋白和纤维蛋白原的结合大大增加，高达50倍。将乳酸杆菌重新暴露于中性pH环境释放大部分结合的蛋白质，但是仍然保持与细胞结合的量比在中性pH下结合的量多数倍。乳酸杆菌还将与构成内皮细胞的细胞外基质的蛋白质结合。乳酸杆菌与I型和V型胶原蛋白的结合显著优于与III型和IV型胶原蛋白的结合（p < 0.01）。此外，从IE病例中分离的菌株，特别是L.鼠李糖菌株与I型和V型的结合显著优于“正常”菌株（p < 0.02）。已证实在内皮损伤部位存在V型胶原。因此，乳酸杆菌，特别是L.因此，该研究表明，考虑用于益生菌目的的乳酸杆菌应针对这些潜在的致病特性进行筛选。
Lactobacilli are often considered to be commensal or beneficial participants in human microbial ecology and considerable research is being carried out into the effects of the use of lactobacilli as additives in both human and animal diets. However, lactobacilli also cause some human diseases (e.g. dental caries, rheumatic vascular disease, septicaemia and infective endocarditis (IE)), and have recently been identified as potential emerging pathogens in elderly and immunocompromised patients, particularly those receiving broad spectrum antibiotic therapy. The identification of potential pathogenic traits amongst lactobacilli will therefore facilitate the use of the organisms for probiotic purposes.The ability to aggregate human platelets is considered to be a possible pathogenic trait in the progression of IE. A comparison of bacterial cell surface properties amongst L. rhamnosus strains showed that platelets were aggregated by 5/5 IE strains and 8/16 laboratory strains. For the L. paracasei subsp. paracasei strains the respective numbers were 2/5 and 2/9. However two strains, morphological mutants of a non-aggregating strain, which had been re-isolated after passaging through rats were found to aggregate platelets. No loss of aggregating function occurred on extensive subculturing of IE strains. Aggregation also occurred with 11/14 strains for five other species, namely, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus oris, Lactobacillus plantarum and Lactobacillus salivarius, with each species being represented indicating that the property is not uncommon in the genus.A comparison of IE and oral isolates of L. rhamnosus and L. paracasei subsp. paracasei and seven other Lactobacillus species, has shown that the binding of both fibronectin and fibrinogen by lactobacilli is greatly increased, up to 50 fold, when the pH is reduced from 7.0 to 5.0. Re-exposing the lactobacilli to a neutral pH environment releases most of the bound proteins, but the amount still remaining bound to the cell is several times more than is bound at neutral pH.Lactobacilli will also bind to the proteins that make up the extracellular matrix of endothelial cells. Lactobacilli bound significantly better to collagen types I and V than to types III and IV (p < 0.01). Further, strains isolated from IE cases, particularly L. rhamnosus strains, bound significantly better to types I and V than did 'normal' strains (p < 0.02). Type V collagen has been demonstrated at the sites of endothelial damage. Thus the binding of lactobacilli, particularly L. rhamnosus to these collagen types may be of importance in the early stages of colonization of the damaged heart valve.The research therefore suggests that lactobacilli being considered for probiotic purposes should be screened for these potentially pathogenic traits.