title: Lactobacillus salivariusandL. gasseridown-regulateAggregatibacter actinomycetemcomitansexotoxins expression.
abstract: 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.Aggregatibacter actinomycetemcomitansis 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 ofA. actinomycetemcomitans.Lactobacillus salivariusandL. gasseriwere selected as beneficial species. The gene expressions of leukotoxin (LtxA) and cytolethal distending toxin (CdtB) byA. actinomycetemcomitanswere analyzed in response to challenge by lactobacilli cell-free supernatants. Neither lactobacilli affected the growth, but strongly attenuated the expressions of bothCdtBandLtxAin the twoA. actinomycetemcomitansstrains 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.
authors.affiliation: Microbiology Area, Department. Agricultural Sciences, Alma Mater Studiorum, Università di Bologna, V.le Fanin 44, 40127 Bologna, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Nissen
authors.affiliation: Microbiology Area, Department. Agricultural Sciences, Alma Mater Studiorum, Università di Bologna, V.le Fanin 44, 40127 Bologna, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Sgorbati
authors.affiliation: Microbiology Area, Department. Agricultural Sciences, Alma Mater Studiorum, Università di Bologna, V.le Fanin 44, 40127 Bologna, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Biavati
authors.affiliation: Oral Microbiology and Immunology, Institute of Oral Biology, Center of Dental Medicine, University of Zürich, Plattenstrasse 11, 8032 Zürich, Switzerland.
authors.forename: Georgios N
authors.initials: GN
authors.lastname: Belibasakis
keywords: Cytolethal distending toxin; Leukotoxin; Oral cavity; Periodontal disease; Probiotics