title: Doxycycline interferes with quorum sensing-mediated virulence factors and biofilm formation in gram-negative bacteria.
abstract: Inhibition of quorum sensing (QS)-regulated virulence factors including biofilm is a recognized anti-pathogenic drug target. The search for safe and effective anti-QS agents is expected to be useful to combat diseases caused by multidrug-resistant bacteria. In this study, effect of a commonly used antibiotic, doxycycline on QS was evaluated using sensor strains of Chromobacterium violaceum (ATCC 12472 and CVO26) and Pseudomonas aeruginosa PAO1. Sub-MICs of doxycycline reduced QS-controlled violacein production in C. violaceum to a significant degree (70 %) and showed a significant reduction of LasB elastase (67.2 %), pyocyanin (69.1 %), chitinase (69.8 %) and protease (65 %) production and swarming motility (74 %) in P. aeruginosa PAO1 over untreated controls. Similar results were also recorded against a clinical strain of P. aeruginosa (PAF-79). Interestingly, doxycycline at respective sub-MICs (4 and 32 μg ml(-1)) significantly reduced the biofilm-forming capability and exopolysaccharide production in both the strains of P. aeruginosa (PAO1 and PAF-79) over untreated controls. The results of this study highlight the multiple actions of doxycycline against QS-linked traits/virulence factors and its potential to attenuate virulence of P. aeruginosa.
authors.affiliation: Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh 202002, UP, India.
authors.forename: Fohad Mabood
authors.initials: FM
authors.lastname: Husain
authors.forename: Iqbal
authors.initials: I
authors.lastname: Ahmad
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects*; D002861:Chromobacterium / Q000187:drug effects* / Q000502:physiology; D004318:Doxycycline / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology; D053038:Quorum Sensing / Q000187:drug effects*; D014774:Virulence / Q000187:drug effects; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D011135:Polysaccharides, Bacterial; D037521:Virulence Factors; D004318:Doxycycline