Pseudomonas aeruginosa Biofilm Antibiotic Resistance GenendvBExpression Requires the RpoS Stationary-Phase Sigma Factor

Abstract

Chronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogen , biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential-phase planktonic cells. One such mechanism involves, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable green fluorescent protein (GFP) transcriptional reporter to observe the expression pattern of We found that in addition to its expression in biofilms, was upregulated in planktonic cells as they enter stationary phase. The transcription of in both growth phases was shown to be dependent on the stationary-phase sigma factor RpoS, and mutation of a putative RpoS binding site in the promoter abolished the activity of the promoter in stationary-phase cells. Overall, we have expanded our understanding of the temporal expression of in and have uncovered a regulatory basis for its growth phase-dependent expression. Bacterial biofilms are more resistant to antibiotics than free-living planktonic cells, and understanding the mechanistic basis of this resistance can inform treatments of biofilm-based infections. In addition to chemical and structural barriers that can inhibit antibiotic entry, the upregulation of specific genes in biofilms contributes to the resistance. We investigated this biofilm-specific gene induction by examining expression patterns of , a gene involved in biofilm resistance of the opportunistic pathogen We characterized expression in planktonic and biofilm growth conditions with an unstable green fluorescent protein (GFP) reporter and found that the expression of in biofilms is dependent on the stationary-phase sigma factor RpoS. Overall, our results support the physiological similarity between biofilms and stationary-phase cells and suggest that the induction of some stationary-phase genes in biofilms may contribute to their increased antibiotic resistance.

Study ndvB gene expression in Pseudomonas aeruginosa Producing Biofilm

“…The PCR tests of ndvB gene confirms the occurrence of P. aerugenosa gene in mainly in all clinical isolates this agreement with Hall et al (17) . The gene expression of ndvB gene increasedafter the treatment with the cefepiem because ofndvB gene has a new resistance mechanism throughformation of periplasmic glucans.…”

The Influence of Selected Plant Essential Oils on Morphological and Physiological Characteristics in Pseudomonas Orientalis

“…Generally, bacteria from Pseudomonas genera are naturally able to produce a large quantity of exopolysaccharides (EPS—extracellular polymeric substances) including proteins and polysaccharides. These substances are synthetized in order to protect cells from adverse physical and chemical factors (such as the lack of water, rapid temperature changes and disinfectants) [51]. Thus, in the first step, it was necessary to estimate the concentration of extracellular proteins in a control probe (without incubation with essential oils).…”

Biofilm Inhibitor Taurolithocholic Acid Alters Colony Morphology, Specialized Metabolism, and Virulence of Pseudomonas aeruginosa

“…[5][6][7] P. aeruginosa infections are often complicated by the fact that it readily forms a multicellular aggregate known as a biofilm -a state which contributes towards its resistance to antibiotics. 8 The minimum bactericidal concentration for cells in a biofilm state is estimated to be 10-1000 times higher than their planktonic counterparts complicating treatment of biofilm infections. 9 Yet, there are currently no biofilm inhibitors on the market in the US.…”