Challenges in using transcriptome data to study the c-di-GMP signaling network in <i>Pseudomonas aeruginosa</i> clinical isolates

Gur, Michal; Erdmann, Jelena; Will, Andrew; Liang, Ziwei; Andersen, Jens Bo; Tolker‐Nielsen, Tim; Häußler, Susanne

doi:10.1093/femsmc/xtad012

Cited by 3 publications

(1 citation statement)

References 42 publications

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“…S1a-c). As the growth phase significantly influences the expression patterns of c-di-GMP-related genes 37 , we cultivated different strains for different periods of time in order for them to reach the same growth phase (i.e. late logphase) (Table S4).…”

Section: Siad (Pa0169) Is Identified As An Essential Dgc Responsible ...mentioning

confidence: 99%

Identification of echinacoside as a tobramycin potentiator againstPseudomonas aeruginosaaggregates

Cai,

Crabbé,

Coenye

2024

Preprint

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Cyclic diguanylate (c-di-GMP) is a central biofilm regulator, where increased intracellular levels promote biofilm formation and antibiotic tolerance. Targeting the c-di-GMP network is a promising anti-biofilm approach. Most agents reported previously decreased c-di-GMP to eliminate surface-attached biofilms, which did not recapitulate in vivo biofilms well and may thus impede their clinical impact. Here, the expression profile of genes encoding proteins associated with c-di-GMP metabolism was analysed among 32 Pseudomonas aeruginosa strains grown as suspended aggregates in synthetic sputum or planktonic cells. A diguanylate cyclase, SiaD, proved essential for auto-aggregation under in vivo-like conditions. Virtual screening against SiaD identified echinacoside as an inhibitor, which reduced intracellular c-di-GMP levels and aggregate sizes and potentiated the efficacy of tobramycin against aggregates established by >80% of tested strains. This synergistic effect was also observed for in vivo-like 3-D alveolar cells infected by cytotoxic P. aeruginosa, demonstrating its high potential as an adjunctive therapy for recalcitrant P. aeruginosa infections.

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Section: Siad (Pa0169) Is Identified As An Essential Dgc Responsible ...mentioning

confidence: 99%

Identification of echinacoside as a tobramycin potentiator againstPseudomonas aeruginosaaggregates

Cai,

Crabbé,

Coenye

2024

Preprint

View full text Add to dashboard Cite

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Surface Hydrophilicity Promotes Bacterial Twitching Motility

O’Hara,

Shimozono,

Dye

et al. 2024

Preprint

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The bacterial type IV pilus (T4P) is a critical virulence factor for many pathogens. These includeAcinetobacter baumanniiandPseudomonas aeruginosa, which are WHO priority pathogens because of their increasing antibiotic resistance. T4P powers bacterial twitching motility which is frequently analyzed by interstitial colony expansion between agar and the polystyrene surfaces of plastic Petri dishes. In such assays with Petri dishes, the twitching motility ofAcinetobacter nosocomialis, an opportunistic human pathogen, was observed with MacConkey but not Luria-Bertani (LB) agar media. One difference between these two media is that bile salts are present as a selective agent in MacConkey but not in LB. We found here that that the addition of bile salts to LB allowedA. nosocomialisto display twitching. Similarly, supplementation of bile salts to LB enhanced the twitching ofA. baumanniiandP. aeruginosa. These observations suggest that there is a common mechanism for bile salts to enhance bacterial twitching to promote interstitial colony expansion. Bile salts are used to inhibit the growth of Gram+ bacteria in MacConkey as they are detergents that can disrupt lipid membranes. Surprisingly, their effects on twitching motility are more related to the alteration of physicochemical properties of twitching surfaces rather than a change in bacterial physiology. This is because bacteria displayed increased twitching motility on hydrophilic surfaces such as those of glass and plasma-treated polystyrene plastics. On such surfaces, twitching motility is no longer stimulated by bile salts. We conclude that the hydrophilicity of surfaces, such as those of animal tissues as well as of medical implants and devices, may significantly impact the functionality of T4P as a virulence factor and its interaction with hosts in the establishment and persistence of a bacterial infection.

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Surface hydrophilicity promotes bacterial twitching motility

O'Hara,

Shimozono,

Dye

et al. 2024

mSphere

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Twitching motility is a form of bacterial surface translocation powered by the type IV pilus (T4P). It is frequently analyzed by interstitial colony expansion between agar and the polystyrene surfaces of petri dishes. In such assays, the twitching motility of Acinetobacter nosocomialis was observed with MacConkey but not Luria-Bertani (LB) agar media. One difference between these two media is the presence of bile salts as a selective agent in MacConkey but not in LB. Here, we demonstrate that the addition of bile salts to LB allowed A. nosocomialis to display twitching. Similarly, bile salts enhanced the twitching of Acinetobacter baumannii and Pseudomonas aeruginosa in LB. These observations suggest that there is a common mechanism, whereby bile salts enhance bacterial twitching and promote interstitial colony expansion. Bile salts disrupt lipid membranes and apply envelope stress as detergents. Surprisingly, their stimulatory effect on twitching appears not to be related to a bacterial physiological response to stressors. Rather, it is due to their ability to alter the physicochemical properties of a twitching surface. We observed that while other detergents promoted twitching like bile salts, stresses applied by antibiotics, including the outer membrane-targeting polymyxin B, did not enhance twitching motility. More importantly, bacteria displayed increased twitching on hydrophilic surfaces such as those of glass and tissue culture-treated polystyrene plastics, and bile salts no longer stimulated twitching on these surfaces. Together, our results show that altering the hydrophilicity of a twitching surface significantly impacts T4P functionality. IMPORTANCE The bacterial type IV pilus (T4P) is a critical virulence factor for many medically important pathogens, some of which are prioritized by the World Health Organization for their high levels of antibiotic resistance. The T4P is known to propel bacterial twitching motility, the analysis of which provides a convenient assay for T4P functionality. Here, we show that bile salts and other detergents augment the twitching of multiple bacterial pathogens. We identified the underlying mechanism as the alteration of surface hydrophilicity by detergents. Consequently, hydrophilic surfaces like those of glass or plasma-treated polystyrene promote bacterial twitching, bypassing the requirement for detergents. The implication is that surface properties, such as those of tissues and medical implants, significantly impact the functionality of bacterial T4P as a virulence determinant. This offers valuable insights for developing countermeasures against the colonization and infection by bacterial pathogens of critical importance to human health on a global scale.

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Challenges in using transcriptome data to study the c-di-GMP signaling network in Pseudomonas aeruginosa clinical isolates

Cited by 3 publications

References 42 publications

Identification of echinacoside as a tobramycin potentiator againstPseudomonas aeruginosaaggregates

Identification of echinacoside as a tobramycin potentiator againstPseudomonas aeruginosaaggregates

Surface Hydrophilicity Promotes Bacterial Twitching Motility

Surface hydrophilicity promotes bacterial twitching motility

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