Honey-induced expression of glutathione-encoding genes (gshA and gshB) in clinical Pseudomonas aeruginosa isolates may reduce the antibacterial potency of honey L'expression induite par le miel des gènes codant pour le glutathion (gshA et gshB) dans les isolats cliniques de Pseudomonas aeruginosa peut réduire la puissance antibactérienne du miel

Abstract

Background: It has been reported in Nigeria that honey has low antibacterial properties against Pseudomonas aeruginosa. Hydrogen peroxide (H₂O₂) is the major contributor to the antimicrobial activity of honey. This research sought to determine whether stress protective glutathione biosynthesis genes (gshA and gshB) present in pathogenic Pseudomonas aeruginosa are associated with its anti-honey resistant nature.
Methodology: The susceptibility of 5 P. aeruginosa clinical strains obtained from Ladoke Akintola University of Technology (LAUTECH) Teaching Hospital Ogbomoso, Nigeria to antibiotics and honey were assessed using disc and agar well diffusion techniques. Detection and expression of P. aeruginosa gshA and gshB genes in the presence of varying dilutions of sweet and bitter Nigerian honey (100%-undiluted, 50%, 25%) and untreated controls, were done using conventional and real-time qPCR, with 16S rRNA gene used as internal control and reference gene to normalize the cDNA samples.
Results: The gshA and gshB genes were detected and expressed in 3 of the 5 selected isolates of P. aeruginosa in the controls (untreated), and in 50% and 25% honey dilutions where they showed down regulation, but in the 100%, the genes were not expressed.
Conclusion: The presence and expression of the glutathione producing genes (gshA and gshB) in P. aeruginosa may reduce the potency of honey as an antibacterial agent by interfering with antibacterial action of H₂O₂ component of honey. Further studies are needed to confirm these genes as hinderances against the successful treatment of bacterial infections caused by P. aeruginosa using honey.