Project description:The widespread presence of antibiotic-resistant bacteria in the environment has been recognized as an important emerging environmental contaminant. Hospital wards, as a special public indoor environment, are of great concern for the risks associated with this emerging environmental contaminant. Pseudomonas aeruginosa, a common nosocomial bacterium, is a contamination risk in the hospital environment due to its drug resistance and transmission of virulence factors. Notably, the antimicrobial peptide-sensing two-component system (TCS) ParRS and CprRS have been implicated in dynorphin-induced signaling, but the underlying Manuscript2 mechanism has remained elusive. In this study, we performed proteomic analysis to systematically investigate the contributions of ParRS and CprRS to P. aeruginosa pathogenesis and dynorphin-induced resistance to polymyxins. Additionally, we characterized the significance of the extracellular sensor domains of ParS and CprS in dynorphin perception. Furthermore, through structural biology, we identified additional TCS sensors with similar extracellular domain conformations, which also directly interacted with dynorphin in vitro. This suggests convergent evolution in different bacterial TCSs for host-derived synthetic peptide signal transmitting. Our findings establish a link between CAMPs resistance associated TCSs and virulence regulation of common nosocomial bacteria. This further illustrates the danger of this emerging contaminant for the environment and humans.
Project description:Using in vitro directed evolution, we show that mismatch repair-deficient Pseudomonas aeruginosa can engage novel resistance mechanisms to ceftazidime-avibactam.
Project description:Antimicrobial peptides (AMPs) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of epinecidin-1 against multi-drug resistant clinical isolates of P. aeruginosa (P. aeruginosa (R)) and P. aeruginosa from ATCC (P. aeruginosa (19660)) in vivo. The minimum inhibitory concentrations (MICs) of epinecidin-1 against P. aeruginosa (R) and P. aeruginosa (19660) were determined, and compared with those of imipenem. Epinecidin-1 was found to be highly effective at combating peritonitis infection caused by P. aeruginosa (R) or P. aeruginosa (19660) in mouse models, without inducing adverse behavioral effects, or liver or kidney toxicity. Taken together, our results indicate that epinecidin-1 enhances the survival rate of mice infected with the bacterial pathogen P. aeruginosa through both antimicrobial and immunomodulatory effects.
Project description:Colistin is an important cationic antimicrobial peptide (CAMP) in the fight against Pseudomonas aeruginosa infection within the cystic fibrosis (CF) lungs. The effects of sub-inhibitory colistin on gene expression in P. aeruginosa were investigated by transcriptome microarray and functional analysis. Analysis revealed an alteration in the expression of 60 genes in total from a variety of pathways. Genes associated with bacterial chronic colonisation and virulence such as response to osmotic stress, motility, and biofilm formation, as well as those associated with LPS modification and quorum sensing are the most highly represented. Most striking among these is the upregulation of the PQS biosynthesis operon including pqsH, pqsE, and the anthranilate biosynthetic genes phnAB. Early activation of this central component of the QS-network may represent a switch to a more robust population, with increased fitness in the competitive environment of the CF-lung.
Project description:Antimicrobial peptides (AMPs) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of epinecidin-1 against multi-drug resistant clinical isolates of P. aeruginosa (P. aeruginosa (R)) and P. aeruginosa from ATCC (P. aeruginosa (19660)) in vivo. The minimum inhibitory concentrations (MICs) of epinecidin-1 against P. aeruginosa (R) and P. aeruginosa (19660) were determined, and compared with those of imipenem. Epinecidin-1 was found to be highly effective at combating peritonitis infection caused by P. aeruginosa (R) or P. aeruginosa (19660) in mouse models, without inducing adverse behavioral effects, or liver or kidney toxicity. Taken together, our results indicate that epinecidin-1 enhances the survival rate of mice infected with the bacterial pathogen P. aeruginosa through both antimicrobial and immunomodulatory effects. RNA from mice treated with epinecidin-1 were individually compared to RNA from PBS control mice.
Project description:In the present study, we employed Affymetrix Pseudomonas aeruginosa GeneChip arrays to investigate global gene expression profiles during the cellular response of Pseudomonas aeruginosa to sodium hypochlorite Keywords: Antimicrobial response
Project description:Peptides have great potential to combat antibiotic resistance. While many platforms can screen peptides for their ability to bind to target cells, there are virtually no platforms that directly assess the functionality of peptides. This limitation is exacerbated when identifying antimicrobial peptides, since the phenotype, death, selects against itself, and has caused a scientific bottleneck confining research to only a few naturally occurring classes of antimicrobial peptides. We have used this seeming dissonance to develop Surface Localized Antimicrobial displaY (SLAY); a platform that allows screening of unlimited numbers of peptides of any length, composition, and structure in a single tube for antimicrobial activity. Using SLAY, we screened ~800,000 random peptide sequences for antimicrobial function and identified thousands of active sequences doubling the number of known antimicrobial sequences. SLAY hits present with different potential mechanisms of peptide action and access to areas of antimicrobial physicochemical space beyond what nature has evolved.
Project description:Peptides have great potential to combat antibiotic resistance. While many platforms can screen peptides for their ability to bind to target cells, there are virtually no platforms that directly assess the functionality of peptides. This limitation is exacerbated when identifying antimicrobial peptides, since the phenotype, death, selects against itself, and has caused a scientific bottleneck confining research to only a few naturally occurring classes of antimicrobial peptides. We have used this seeming dissonance to develop Surface Localized Antimicrobial displaY (SLAY); a platform that allows screening of unlimited numbers of peptides of any length, composition, and structure in a single tube for antimicrobial activity. Using SLAY, we screened ~800,000 random peptide sequences for antimicrobial function and identified thousands of active sequences doubling the number of known antimicrobial sequences. SLAY hits present with different potential mechanisms of peptide action and access to areas of antimicrobial physicochemical space beyond what nature has evolved.
Project description:We carried out an experimental evolution in human serum as an ex-vivo model and screened evolved lines for the evolution of resistance phenotypes towards two anti-virulence treatments, gallium and flucytosine, which both target the iron scavenging pyoverdine of Pseudomonas aeruginosa (each at 2 different doses). We performed whole-genome sequencing of 16 evolved clones from the different treatment regimes .
Project description:Cationic antimicrobial peptides (CAPs) are promising novel alternatives to conventional antibacterial agents, but the overlap in resistance mechanisms between small-molecule antibiotics and CAPs is unknown. Does evolution of antibiotic resistance decrease (cross-resistance) or increase (collateral sensitivity) susceptibility to CAPs? We systematically addressed this issue by studying the susceptibilities of a comprehensive set of antibiotic resistant Escherichia coli strains towards 24 antimicrobial peptides. Strikingly, antibiotic resistant bacteria frequently showed collateral sensitivity to CAPs, while cross-resistance was relatively rare. We identified clinically relevant multidrug resistance mutations that simultaneously elevate susceptibility to certain CAPs. Transcriptome and chemogenomic analysis revealed that such mutations frequently alter the lipopolysaccharide composition of the outer cell membrane and thereby increase the killing efficiency of membrane-interacting antimicrobial peptides. Furthermore, we identified CAP-antibiotic combinations that rescue the activity of existing antibiotics and slow down the evolution of resistance to antibiotics. Our work provides a proof of principle for the development of peptide based antibiotic adjuvants that enhance antibiotic action and block evolution of resistance.