Differential surface competition and biofilm invasion strategies of Pseudomonas aeruginosa PA14 and PA01

Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best characterized model organisms used to study the mechanisms of biofilm formation, while also representing two distinct lineages of P. aeruginosa . Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, the P. aeruginosa PA14 is better able to invade pre-formed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. Importance Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naïve surface, while PA14 is more effective in colonizing a pre-formed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.

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An In Vitro Coumarin-Antibiotic Combination Treatment of Pseudomonas aeruginosa Biofilms

Natural Product Communications ◽

10.1177/1934578x20987744 ◽

2021 ◽

Vol 16 (1) ◽

pp. 1934578X2098774

Author(s):

Jinpeng Zou ◽

Yang Liu ◽

Ruiwei Guo ◽

Yu Tang ◽

Zhengrong Shi ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Drug Resistance ◽

Combination Treatment ◽

Crude Extract ◽

Biofilm Formation ◽

Bacterial Resistance ◽

Antibacterial Properties ◽

Biofilm Growth ◽

Antibiotic Combination

The drug resistance of Pseudomonas aeruginosa is a worldwide problem due to its great threat to human health. A crude extract of Angelica dahurica has been proved to have antibacterial properties, which suggested that it may be able to inhibit the biofilm formation of P. aeruginosa; initial exploration had shown that the crude extract could inhibit the growth of P. aeruginosa effectively. After the adaptive dose of coumarin was confirmed to be a potential treatment for the bacteria’s drug resistance, “coumarin-antibiotic combination treatments” (3 coumarins—simple coumarin, imperatorin, and isoimperatorin—combined with 2 antibiotics—ampicillin and ceftazidime) were examined to determine their capability to inhibit P. aeruginosa. The final results showed that (1) coumarin with either ampicillin or ceftazidime significantly inhibited the biofilm formation of P. aeruginosa; (2) coumarin could directly destroy mature biofilms; and (3) the combination treatment can synergistically enhance the inhibition of biofilm formation, which could significantly reduce the usage of antibiotics and bacterial resistance. To sum up, a coumarin-antibiotic combination treatment may be a potential way to inhibit the biofilm growth of P. aeruginosa and provides a reference for antibiotic resistance treatment.

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Tryptophan Inhibits Biofilm Formation by Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00007-13 ◽

2013 ◽

Vol 57 (4) ◽

pp. 1921-1925 ◽

Cited By ~ 39

Author(s):

Kenneth S. Brandenburg ◽

Karien J. Rodriguez ◽

Jonathan F. McAnulty ◽

Christopher J. Murphy ◽

Nicholas L. Abbott ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Tissue Culture ◽

Biofilm Formation ◽

Chronic Wounds ◽

Inhibitory Effect ◽

Equimolar Ratio ◽

Biofilm Growth ◽

Content Type ◽

Swimming Motility

ABSTRACTBiofilm formation byPseudomonas aeruginosahas been implicated in the pathology of chronic wounds. Both thedandlisoforms of tryptophan inhibitedP. aeruginosabiofilm formation on tissue culture plates, with an equimolar ratio ofdandlisoforms producing the greatest inhibitory effect. Addition ofd-/l-tryptophan to existing biofilms inhibited further biofilm growth and caused partial biofilm disassembly. Tryptophan significantly increased swimming motility, which may be responsible in part for diminished biofilm formation byP. aeruginosa.

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An integrated model system to gain mechanistic insights into biofilm formation and antimicrobial resistance development in Pseudomonas aeruginosa MPAO1

10.1101/2020.02.06.936690 ◽

2020 ◽

Cited By ~ 3

Author(s):

Adithi R. Varadarajan ◽

Raymond N. Allan ◽

Jules D. P. Valentin ◽

Olga E. Castañeda Ocampo ◽

Vincent Somerville ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Biofilm Formation ◽

Soft Lithography ◽

Flow Chamber ◽

Model System ◽

Secretion Systems ◽

Phenotypic Data ◽

Biofilm Growth ◽

Mutant Collection

AbstractPseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and antibiotic resistance.Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and missed genes by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq datasets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth. Experiments conducted across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated both known and novel genes involved in biofilm growth and antibiotic resistance identified in screens of the mutant collection. Differential protein expression data from planktonic cells versus biofilm confirmed upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type six secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance and resistance evolution.

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New Insights into the Effects of Several Environmental Parameters on the Relative Fitness of a Numerically Dominant Class of Evolved Niche Specialist

International Journal of Evolutionary Biology ◽

10.1155/2016/4846565 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Anna Kuśmierska ◽

Andrew J. Spiers

Keyword(s):

Biofilm Formation ◽

Environmental Parameters ◽

Optimal Growth ◽

Model System ◽

Relative Fitness ◽

Ecological Opportunity ◽

Competitive Fitness ◽

Fitness Advantage ◽

Main Driver ◽

Simple Model System

Adaptive radiation in bacteria has been investigated using Wrinkly Spreaders (WS), a morphotype which colonises the air-liquid (A-L) interface of static microcosms by biofilm formation with a significant fitness advantage over competitors growing lower down in the O2-limited liquid column. Here, we investigate several environmental parameters which impact the ecological opportunity that the Wrinkly Spreaders exploit in this model system. Manipulation of surface area/volume ratios suggests that the size of the WS niche was not as important as the ability to dominate the A-L interface and restrict competitor growth. The value of this niche to the Wrinkly Spreaders, as determined by competitive fitness assays, was found to increase as O2 flux to the A-L interface was reduced, confirming that competition for O2 was the main driver of WS fitness. The effect of O2 on fitness was also found to be dependent on the availability of nutrients, reflecting the need to take up both for optimal growth. Finally, the meniscus trap, a high-O2 region formed by the interaction of the A-L interface with the vial walls, was also important for fitness during the early stages of biofilm formation. These findings reveal the complexity of this seemingly simple model system and illustrate how changes in environmental physicality alter ecological opportunity and the fitness of the adaptive morphotype.

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An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1

npj Biofilms and Microbiomes ◽

10.1038/s41522-020-00154-8 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Adithi R. Varadarajan ◽

Raymond N. Allan ◽

Jules D. P. Valentin ◽

Olga E. Castañeda Ocampo ◽

Vincent Somerville ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Biofilm Formation ◽

Soft Lithography ◽

Flow Chamber ◽

Model System ◽

Secretion Systems ◽

Phenotypic Data ◽

Biofilm Growth ◽

Resistance Evolution

Abstract Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms.

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Engineered lactobacilli display anti-biofilm and growth suppressing activities against Pseudomonas aeruginosa

10.1101/2020.04.08.032946 ◽

2020 ◽

Author(s):

Todd C. Chappell ◽

Nikhil U. Nair

Keyword(s):

Pseudomonas Aeruginosa ◽

Lactic Acid ◽

Biofilm Formation ◽

Antimicrobial Treatment ◽

Infection Site ◽

Planktonic Cells ◽

Biofilm Growth ◽

Growth State ◽

Development Of Resistance ◽

Pathogen Load

AbstractBiofilms are an emerging target for new therapeutics in the effort to address the continued increase in resistance and tolerance to traditional antimicrobials. In particular, the distinct nature of the biofilm growth state often means that traditional antimicrobials, developed to combat planktonic cells, are ineffective. Biofilm treatments are designed to both reduce pathogen load at an infection site and decrease the development of resistance by rendering the embedded organisms more susceptible to treatment at lower antimicrobial concentrations. In this work, we developed a new antimicrobial treatment modality by characterizing the natural capacity of two lactobacilli, L. plantarum and L. rhamnosus, to inhibit P. aeruginosa growth, biofilm formation, and biofilm viability. We further engineered these lactic acid bacteria (LAB) to secrete enzymes known to degrade P. aeruginosa biofilms and show that our best performing engineered LAB, secreting a pathogen-derived enzyme (PelAhyd), degrades up to 85 % of P. aeruginosa biofilm.

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Antimicrobial Resistance in Pseudomonas aeruginosa Biofilms

Journal of Pure and Applied Microbiology ◽

10.22207/jpam.15.4.79 ◽

2021 ◽

Author(s):

Dhara Patel ◽

Palash Sen ◽

Yin Hlaing ◽

Michael Boadu ◽

Bassam Saadeh ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Multidrug Resistance ◽

Antimicrobial Resistance ◽

Growth Inhibition ◽

Biofilm Formation ◽

Broth Microdilution ◽

Planktonic Cells ◽

Biofilm Growth ◽

Minimal Inhibitory Concentrations ◽

Dose Dependent

Pseudomonas aeruginosa (PA) is part of a group of common nosocomial pathogens that exhibit multidrug resistance, thus proving to be a significant threat to healthcare. This study analyzes the ability of four commonly used antibiotics to observe eradication of the PA biofilm growth. Ceftazidime (CAZ), Tobramycin (TOB), Ofloxacin (OFLX), Meropenem (MEM), were tested against overnight cultures of PA strain PA01. The minimal inhibitory concentrations (MIC) of planktonic cells for all the four antibiotics were determined using broth microdilution while the minimal bactericidal concentrations (MBCs) were determined by colony count after antibiotic treatment and regrowth. Biofilm growth inhibition was performed by treating cells with antibiotic at the time of inoculation while eradication was determined by adding antibiotics 24 hours after inoculation, allowing mature biofilm formation, followed by the measurement of absorbance. PA planktonic cells exhibited the highest susceptibility to MEM compared to overnight grown PA biofilm which demonstrated resistance to CAZ, complete sensitivity to ofloxacin, and minimal sensitivity to TOB and MEM. PA biofilm displayed dose-dependent sensitivity to TOB, MEM and OFLX, and a significant level of resistance to CAZ during the inhibition phase. However, in the eradication phase, PA showed significant resistance to TOB followed by CAZ while PA biofilm showed sensitivity at higher concentrations of MEM. Our study exhibits that PA strain PA01 is resistant to ceftazidime in both planktonic and biofilm phases. While ofloxacin proved to be the most effective even at lower concentrations when compared with other antibiotics, tobramycin was most effective at higher concentrations for eradicating and inhibiting PA biofilms.

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Three biofilm types produced by a model pseudomonad are differentiated by structural characteristics and fitness advantage

Microbiology ◽

10.1099/mic.0.000938 ◽

2020 ◽

Vol 166 (8) ◽

pp. 707-716 ◽

Cited By ~ 1

Author(s):

Anna Koza ◽

Robyn Jerdan ◽

Scott Cameron ◽

Andrew J. Spiers

Keyword(s):

Biofilm Formation ◽

Structural Characteristics ◽

Growth Conditions ◽

Bacterial Biofilm ◽

Physical Disturbance ◽

Physiological Factors ◽

Competitive Fitness ◽

Content Type ◽

Fitness Advantage ◽

Viscous Mass

Model bacterial biofilm systems suggest that bacteria produce one type of biofilm, which is then modified by environmental and physiological factors, although the diversification of developing populations might result in the appearance of adaptive mutants producing altered structures with improved fitness advantage. Here we compare the air–liquid (A–L) interface viscous mass (VM) biofilm produced by Pseudomonas fluorescens SBW25 and the wrinkly spreader (WS) and complementary biofilm-forming strain (CBFS) biofilm types produced by adaptive SBW25 mutants in order to better understand the link between these physical structures and the fitness advantage they provide in experimental microcosms. WS, CBFS and VM biofilms can be differentiated by strength, attachment levels and rheology, as well as by strain characteristics associated with biofilm formation. Competitive fitness assays demonstrate that they provide similar advantages under static growth conditions but respond differently to increasing levels of physical disturbance. Pairwise competitions between biofilms suggest that these strains must be competing for at least two growth-limiting resources at the A–L interface, most probably O2 and nutrients, although VM and CBFS cells located lower down in the liquid column might provide an additional fitness advantage through the colonization of a less competitive zone below the biofilm. Our comparison of different SBW25 biofilm types illustrates more generally how varied biofilm characteristics and fitness advantage could become among adaptive mutants arising from an ancestral biofilm–forming strain and raises the question of how significant these changes might be in a range of medical, biotechnological and industrial contexts where diversification and change may be problematic.

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Increased production of the extracellular polysaccharide Psl can give a growth advantage to Pseudomonas aeruginosa in low-iron conditions

10.1101/355339 ◽

2018 ◽

Cited By ~ 1

Author(s):

Jaime Hutchison ◽

Karishma Kaushik ◽

Christopher A. Rodesney ◽

Thomas Lilieholm ◽

Layla Bakhtiari ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Iron Acquisition ◽

Single Cells ◽

Extracellular Polysaccharide ◽

Time Lapse ◽

Evolutionary Development ◽

Intercellular Signaling ◽

Biofilm Growth

AbstractIn infections, biofilm formation is associated with a number of fitness advantages, such as resistance to antibiotics and to clearance by the immune system. Biofilm formation has also been linked to fitness advantages in environments other than in vivo infections; primarily, biofilms are thought to help constituent organisms evade predation and to promote intercellular signaling. The opportunistic human pathogen Pseudomonas aeruginosa forms biofilm infections in lungs, wounds, and on implants and medical devices. However, the tendency toward biofilm formation originated in this bacterium’s native environment, primarily plants and soil. Such environments are polymicrobial and often resource-limited. Other researchers have recently shown that the P. aeruginosa extracellular polysaccharide Psl can bind iron. For the lab strain PA01, Psl is also the dominant adhesive and cohesive “glue” holding together multicellular aggregates and biofilms. Here, we perform quantitative time-lapse confocal microscopy and image analysis of early biofilm growth by PA01. We find that aggregates of P. aeruginosa have a growth advantage over single cells of P. aeruginosa in the presence of Staphylococcus aureus in low-iron environments. Our results suggest the growth advantage of aggregates is linked to their high Psl content and to the production of an active factor by S. aureus. We posit that the ability of Psl to promote iron acquisition may have been linked to the evolutionary development of the strong biofilm-forming tendencies of P. aeruginosa.

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