Kart D, Reçber T, Nemutlu E, Sagiroglu M. Sub-Inhibitory Concentrations of Ciprofloxacin Alone and Combinations with Plant-Derived Compounds against
P. aeruginosa Biofilms and Their Effects on the Metabolomic Profile of
P. aeruginosa Biofilms.
Antibiotics (Basel) 2021;
10:antibiotics10040414. [PMID:
33918895 PMCID:
PMC8070142 DOI:
10.3390/antibiotics10040414]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION
Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level.
MATERIALS AND METHODS
The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using minimum biofilm eradication concentration (MBEC) and virulence assays. The effects of ciprofloxacin and compound combinations on P. aeruginosa in mono and triple biofilms were compared. A metabolomic approach and qRT-PCR were applied to the biofilms treated with ciprofloxacin in combination with baicalein, esculin hydrate, curcumin, and cinnamaldehyde at sub-minimal biofilm inhibitory concentration (MBIC) concentrations to highlight the specific metabolic shifts between the biofilms and to determine the quorum sensing gene expressions, respectively.
RESULTS
The combinations of ciprofloxacin with curcumin, baicalein, esculetin, and cinnamaldehyde showed more reduced MBICs than ciprofloxacin alone. The quorum sensing genes were downregulated in the presence of curcumin and cinnamaldehyde, while upregulated in the presence of baicalein and esculin hydrate rather than for ciprofloxacin alone. The combinations exhibited different killing effects on P. aeruginosa in mono and triple biofilms without affecting its virulence. The findings of the decreased metabolite levels related to pyrimidine and lipopolysaccharide synthesis and to down-regulated alginate and lasI expressions strongly indicate the role of multifactorial mechanisms for curcumin-mediated P. aeruginosa growth inhibition.
CONCLUSIONS
The use of curcumin, baicalein, esculetin, and cinnamaldehyde with ciprofloxacin will help fight against P. aeruginosa biofilms. To the best of our knowledge, this is the first study of its kind to define the effect of plant-based compounds as possible anti-biofilm agents with low MBICs for the treatment of P. aeruginosa biofilms through metabolomic pathways.
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