Data from: Strain identification and quorum sensing inhibition characterization of marine-derived Rhizobium sp. NAO1

A novel strategy for combating pathogens is through the ongoing
development and use of anti-quorum sensing (QS) treatments such as
therapeutic bacteria or their anti-QS substances. Relatively little is
known about the bacteria that inhabit the open ocean and of their
potential anti-pathogenic attributes; thus, in an initiative to identify
these types of therapeutic bacteria, planktonic microbes from the North
Atlantic Ocean were collected, isolated, cultured and screened for anti-QS
activity. Screening analysis identified one such strain, Rhizobium sp.
NAO1. Extracts of Rhizobium sp. NAO1 were identified via ultra-performance
liquid chromatography (UPLC) analysis. They were shown to contain N-acyl
homoserine lactone (AHL)-based QS analogues (in particular, the N-butyryl
homoserine lactone (C4-AHL) analogue) and could disrupt biofilm formation
by Pseudomonas aeruginosa PAO1. QS inhibition was confirmed using confocal
scanning laser microscopy and growth curves, and it was shown to occur in
a dose-dependent manner without affecting bacterial growth. Secondary
metabolites of Rhizobium sp. NAO1 inhibited PAO1 pathogenicity by
downregulating AHL-mediated virulence factors such as elastase activity
and siderophore production. Furthermore, as a result of biofilm structure
damage, the secondary metabolite products of Rhizobium sp. NAO1
significantly increased the sensitivity of PAO1 to aminoglycoside
antibiotics. Our results demonstrated that Rhizobium sp. strain NAO1 has
the ability to disrupt P. aeruginosa PAO1 biofilm architecture, in
addition to attenuating P. aeruginosa PAO1 virulence factor production and
pathogenicity. Therefore, the newly identified ocean-derived Rhizobium sp.
NAO1 has the potential to serve as a QS inhibitor and may be a new
microbial resource for drug development.