Nissen Lorenzo, Sgorbati Barbara, Biavati Bruno, Belibasakis Georgios N
Microbiology Area, Department. Agricultural Sciences, Alma Mater Studiorum, Università di Bologna, V.le Fanin 44, 40127 Bologna, Italy.
Oral Microbiology and Immunology, Institute of Oral Biology, Center of Dental Medicine, University of Zürich, Plattenstrasse 11, 8032 Zürich, Switzerland.
Ann Microbiol. 2014;64(2):611-617. doi: 10.1007/s13213-013-0694-x. Epub 2013 Aug 4.
Beneficial microbes, such as lactobacilli establish a symbiosis with the host and confer health-associated effects, by limiting the growth of indigenous pathogens and challenging microbes introduced by altered foods. Nevertheless, there is scarce information on the effects of beneficial microbes on the virulence properties of bacterial species associated with oral diseases, such as periodontitis. is a Gram-negative species highly implicated in the etiology of localized aggressive periodontitis. The objective of this study was to investigate the effect of lactobacilli on the expression of the two major virulence factors of . and were selected as beneficial species. The gene expressions of leukotoxin () and cytolethal distending toxin () by were analyzed in response to challenge by lactobacilli cell-free supernatants. Neither lactobacilli affected the growth, but strongly attenuated the expressions of both and in the two strains tested. This reduction of the expression of these two exotoxins was time-dependent. These fundamental findings may indicate that lactobacilli can reduce the virulence of putative opportunistic oral pathogens, and may provide insights to future therapeutic approaches for the respective diseases.
有益微生物，如乳酸菌，与宿主建立共生关系，并通过限制本土病原体的生长以及抑制因食物变化而引入的挑战性微生物，从而产生与健康相关的影响。然而，关于有益微生物对与口腔疾病（如牙周炎）相关的细菌物种毒力特性影响的信息却很少。伴放线聚集杆菌是一种革兰氏阴性菌，与局限性侵袭性牙周炎的病因高度相关。本研究的目的是调查乳酸菌对伴放线聚集杆菌两种主要毒力因子表达的影响。嗜酸乳杆菌和植物乳杆菌被选为有益菌种。通过无细胞上清液对伴放线聚集杆菌进行刺激，分析其白细胞毒素（ltxA）和细胞致死膨胀毒素（cdtA）的基因表达。两种乳酸菌均不影响伴放线聚集杆菌的生长，但在测试的两株伴放线聚集杆菌菌株中均强烈减弱了ltxA和cdtA的表达。这两种外毒素表达的降低具有时间依赖性。这些重要发现可能表明，乳酸菌可以降低假定的机会性口腔病原体的毒力，并可能为未来针对相应疾病的治疗方法提供思路。
