Effect of trans-Cinnamaldehyde on Methicillin-Resistant Staphylococcus aureus Biofilm Formation: Metabolic Activity Assessment and Analysis of the Biofilm-Associated Genes Expression

Abstract

The effects of trans-cinnamaldehyde (TC) on transcriptional profiles of biofilm-associated genes and the metabolic activity of two methicillin-resistant Staphylococcus aureus (MRSA) strains showing a different degree of adherence to polystyrene, were evaluated. Metabolic activity of S. aureus in biofilm was significantly decreased in the presence of TC at 1/2 minimum biofilm inhibition concentration (MBIC). Expression levels of the genes encoding laminin binding protein (eno), elastin binding protein (ebps) and fibrinogen binding protein (fib) in the presence of TC at 1/2 MBIC were lower than in untreated biofilm in both the weakly and strongly adhering strain. The highest decrease of expression level was observed in case of fib in the strongly adhering strain, in which the amount of fib transcript was 10-fold lower compared to biofilm without TC. In the presence of TC at 1/2 MBIC after 3, 6, 8 and 12 h, the expression level of icaA and icaD, that are involved in the biosynthesis of polysaccharide intercellular adhesin, was above half lower in the weakly adhering strain compared to biofilm without TC. In the strongly adhering strain the highest decrease in expression of these genes was observed after 3 and 6 h. This study showed that TC is a promising anti-biofilm agent for use in MRSA biofilm-related infections.

Effect of manuka honey on biofilm-associated genes expression during methicillin-resistant Staphylococcus aureus biofilm formation

“…Serial twofold dilutions of honey were prepared to obtain concentrations ranging from 50% to 1.56%. Determination of MBIC and MBEC of manuka honey was carried out according to method described earlier by Kot et al 35 .…”

“…Control of bacterial growth was performed in the wells with bacterial cell suspensions without manuka honey, as well as control of sterility of the media (wells without addition of bacterial cell suspension). Bacterial cell viability in biofilms, after the appropriate incubation period, was determined by the resazurin microtiter-plate assay as described earlier 35 . Metabolic assay is excellent for the quantification of bacterial viability in biofilm, and the amount of metabolite produced by a biofilm depends on both the metabolic activity of the individual bacteria and the number of live bacteria in the biofilm.…”

An Overview of the Potential Therapeutic Applications of Essential Oils

“…In regard to EO activity on bacterial genes, it has been found that rosemary and Baccharis psiadioides EO have shown a bacteriostatic effect that impacts the development and functions of bacterial cells of L. monocytogenes by upregulating and downregulating stress and virulence genes such as actA , and hly , thus reducing bacterial virulence [ 136 ]. In addition, by using scanning electron microscopy, qPCR, and a 96-well plate method, cinnamon oil has been found to have activity against the expression of icaA gene and biofilms of S. epidermidis [ 137 ]. Furthermore, confocal laser scanning microscopy (CLSM) has shown that cinnamaldehyde is able to kill the tested bacteria, thus indicating its effectiveness in biofilms [ 137 ].…”

“…In addition, by using scanning electron microscopy, qPCR, and a 96-well plate method, cinnamon oil has been found to have activity against the expression of icaA gene and biofilms of S. epidermidis [ 137 ]. Furthermore, confocal laser scanning microscopy (CLSM) has shown that cinnamaldehyde is able to kill the tested bacteria, thus indicating its effectiveness in biofilms [ 137 ]. All these findings prove that different EO can modulate gene expression by upregulating and downregulating stress and virulence genes of different microorganisms.…”

Trans-cinnamaldehyde attenuatesEnterococcus faecalisvirulence and inhibits biofilm formation

“…Trans -cinnamaldehyde (TC) is an aromatic aldehyde, which predominately exists in cinnamon essential oils [20, 21]. It has been shown to have antimicrobial and antibiofilm activities against a wide range of bacterial pathogens including Pseudomonas aeruginosa [22, 23], Escherichia coli [24, 25], Staphylococcus aureus [26,27], Staphylococcus epidermidis [28], and Streptococcus mutans [29]. There is some evidence to show that TC inhibits growth of E. faecalis [30, 31], without inducing an adaptive phenotype [31].…”