scholarly journals Single-Cell Imaging Reveals That Staphylococcus aureus Is Highly Competitive Against Pseudomonas aeruginosa on Surfaces

2021 ◽  
Vol 11 ◽  
Author(s):  
Selina Niggli ◽  
Tobias Wechsler ◽  
Rolf Kümmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Single Cell ◽  
Treatment Options ◽  
Time Lapse ◽  
Physical Contact ◽  
Automated Image Analysis ◽  
Competitive Balance ◽  
Directional Growth ◽  
Polymicrobial Infections

Pseudomonas aeruginosa and Staphylococcus aureus frequently occur together in polymicrobial infections, and their interactions can complicate disease progression and treatment options. While interactions between P. aeruginosa and S. aureus have been extensively described using planktonic batch cultures, little is known about whether and how individual cells interact with each other on solid substrates. This is important because both species frequently colonize surfaces to form aggregates and biofilms in infections. Here, we performed single-cell time-lapse fluorescence microscopy, combined with automated image analysis, to describe interactions between P. aeruginosa PAO1 with three different S. aureus strains (Cowan I, 6850, JE2) during microcolony growth on agarose surfaces. While P. aeruginosa is usually considered the dominant species, we found that the competitive balance tips in favor of S. aureus on surfaces. We observed that all S. aureus strains accelerated the onset of microcolony growth in competition with P. aeruginosa and significantly compromised P. aeruginosa growth prior to physical contact. Upon direct contact, JE2 was the most competitive S. aureus strain, simply usurping P. aeruginosa microcolonies, while 6850 was the weakest competitor itself suppressed by P. aeruginosa. Moreover, P. aeruginosa reacted to the assault of S. aureus by showing increased directional growth and expedited expression of quorum sensing regulators controlling the synthesis of competitive traits. Altogether, our results reveal that quantitative single-cell live imaging has the potential to uncover microbial behaviors that cannot be predicted from batch culture studies, and thereby contribute to our understanding of interactions between pathogens that co-colonize host-associated surfaces during polymicrobial infections.

scholarly journals Single-cell imaging reveals that Staphylococcus aureus is highly competitive against Pseudomonas aeruginosa on surfaces

2021 ◽  
Author(s):  
Selina Niggli ◽  
Tobias Wechsler ◽  
Rolf Kümmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Single Cell ◽  
Resource Competition ◽  
Interference Competition ◽  
Physical Contact ◽  
Automated Image Analysis ◽  
Competitive Balance ◽  
Directional Growth ◽  
Polymicrobial Infections

Pseudomonas aeruginosa and Staphylococcus aureus frequently occur together in polymicrobial infections, and their interactions can complicate disease progression as well as treatment options. While interactions between P. aeruginosa and S. aureus have been extensively described using planktonic batch cultures, little is known about whether and how individual cells interact with each other on solid substrates. This is important, because in infections, both species frequently colonize surfaces to form microcolony aggregates and biofilms. Here, we performed single-cell time-lapse fluorescence microscopy combined with automated image analysis to describe interactions between P. aeruginosa PAO1 with three different S. aureus strains (Cowan I, 6850, JE2) during microcolony growth on agarose surfaces. While P. aeruginosa is usually considered the dominant species, we found that the competitive balance tips in favor of S. aureus on surfaces. We observed that all S. aureus strains accelerated the onset of microcolony growth in competition with P. aeruginosa and significantly compromised P. aeruginosa growth prior to physical contact. These results suggest that S. aureus deploys mechanisms of both resource competition and interference competition via diffusible compounds. JE2 was the most competitive S. aureus strain, simply usurping P. aeruginosa microcolonies when coming into direct contact, while 6850 was the weakest competitor itself suppressed by P. aeruginosa. Moreover, P. aeruginosa reacted to the assault of S. aureus by showing increased directional growth and expedited expression of quorum sensing regulators controlling the synthesis of competitive traits. Altogether, our results reveal that quantitative single-cell live imaging has the potential to uncover microbial behaviors that cannot be predicted from batch culture studies, and thereby contribute to our understanding of interactions between pathogens that co-colonize host-associated surfaces during polymicrobial infections. 

scholarly journals Rapid and strain-specific resistance evolution of Staphylococcus aureus against inhibitory molecules secreted by Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Selina Niggli ◽  
Lucy Poveda ◽  
Jonas Grossmann ◽  
Rolf Kuemmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Treatment Options ◽  
Membrane Transporters ◽  
Resistance Evolution ◽  
Virulence Traits ◽  
Growth Inhibitory ◽  
Inhibitory Molecules ◽  
And Staphylococcus Aureus ◽  
Polymicrobial Infections

Pseudomonas aeruginosa and Staphylococcus aureus frequently occur together in polymicrobial infections, and there is evidence that their interactions negatively affect disease outcome in patients. At the molecular level, interactions between the two bacterial taxa are well-described, with P. aeruginosa usually being the dominant species suppressing S. aureus through a variety of inhibitory molecules. However, in polymicrobial infections, the two species interact over prolonged periods of time, and S. aureus might evolve resistance against inhibitory molecules deployed by P. aeruginosa. Here, we used experimental evolution to test this hypothesis by exposing three different S. aureus strains (Cowan I, 6850, JE2) to the growth-inhibitory supernatant of P. aeruginosa PAO1 over 30 days. We found that all three S. aureus strains rapidly evolved resistance against inhibitory molecules and show that (i) adaptations were strain-specific; (ii) resistance evolution affected the expression of virulence traits; and (iii) mutations in membrane transporters were the most frequent evolutionary targets. Our work indicates that adaptations of S. aureus to co-infecting pathogens could increase virulence and decrease antibiotic susceptibility, because both virulence traits and membrane transporters involved in drug resistance were under selection. Thus, pathogen co-evolution could exacerbate infections and compromise treatment options.

scholarly journals Multiple Compounds Secreted by Pseudomonas aeruginosa Increase the Tolerance of Staphylococcus aureus to the Antimicrobial Metals Copper and Silver

mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Nadia K. Monych ◽  
Raymond J. Turner
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Chemical Communication ◽  
Single Species ◽  
Species Group ◽  
Chronic Infections ◽  
Content Type ◽  
Alternative Antimicrobials ◽  
Polymicrobial Infections

Alternative antimicrobials, such as metals, are one of the methods currently used to help mitigate antibiotic resistance. Metal-based antimicrobials such as copper and silver are used currently both to prevent and to treat infections. Although the efficacy of these antimicrobials has been determined in single-species culture, bacteria rarely exist in a single-species group in the environment. Both Pseudomonas aeruginosa and Staphylococcus aureus are often found associated with each other in severe chronic infections displaying increased virulence and antibiotic tolerance. In this study, we determined that multiple compounds secreted by P. aeruginosa are able to increase the tolerance of S. aureus to both copper and silver. This work demonstrates the expansive chemical communication occurring in polymicrobial infections between bacteria.

scholarly journals The inhibitory effects of Staphylococcus aureus on the antibiotic susceptibility and virulence factors of Pseudomonas aeruginosa: A549 cell line model

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sanaz Dehbashi ◽  
Mohammad Yousef Alikhani ◽  
Hamed Tahmasebi ◽  
Mohammad Reza Arabestani
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Cell Line ◽  
Virulence Factors ◽  
A549 Cell ◽  
Virulent Strain ◽  
Inhibitory Effect ◽  
A549 Cell Line ◽  
Polymicrobial Infections

AbstractPseudomonas aeruginosa and Staphylococcus aureus often lead to serious lung infections. This study aimed to investigate the role of S. aureus in the expression of the β-lactamase enzymes and virulence factors of P. aeruginosa in the polymicrobial infections of the respiratory tract. Biofilm and planktonic co-culture of P. aeruginosa and S. aureus were performed in the A549 cell line. Then, antibiotic resistance and virulence factors of P. aeruginosa were examined, and the expression of lasR, lasI, algD, mexR, and KPC genes were determined using qPCR. S.aureus decreased β-lactam resistance but increased resistance to tobramycin in the biofilm condition. Furthermore, S.aureus showed a positive effect on reducing resistance to meropenem, doripenem, and tobramycin (except PA-2). Altough it was demonstrated that S.aureus reduced the viability of P. aeruginosa, particularly in the biofilm state, the pathogenicity of the recovered strains of P.aeruginosa increased. Moreover, the gene expression levels for lasR/I and algD were increased in biofilm conditions. The levels of lasI were more prominent in the virulent strain than the β-lactamase producing strain. Furthermore, the expression of KPC was increased in all strains of P. aeruginosa. According to the findings of this study, S. aureus has an inhibitory effect in polymicrobial infections by suppressing the β-lactamase genes and viability of P. aeruginosa. Also, it cooperates with the biofilm-producing P. aeruginosa strains to increase pathogenicity and resistance to tobramycin.

scholarly journals Strain Background, Species Frequency, and Environmental Conditions Are Important in Determining Pseudomonas aeruginosa and Staphylococcus aureus Population Dynamics and Species Coexistence

2020 ◽  
Vol 86 (18) ◽  
Author(s):  
Selina Niggli ◽  
Rolf Kümmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Population Dynamics ◽  
Environmental Conditions ◽  
Species Coexistence ◽  
Content Type ◽  
Species Frequency ◽  
Culturing Conditions ◽  
Polymicrobial Infections ◽  
Strain Background

ABSTRACT Bacterial communities in the environment and in infections are typically diverse, yet we know little about the factors that determine interspecies interactions. Here, we apply concepts from ecological theory to understand how biotic and abiotic factors affect interaction patterns between the two opportunistic human pathogens Pseudomonas aeruginosa and Staphylococcus aureus, which often cooccur in polymicrobial infections. Specifically, we conducted a series of short- and long-term competition experiments between P. aeruginosa PAO1 (as our reference strain) and three different S. aureus strains (Cowan I, 6850, and JE2) at three starting frequencies and under three environmental (culturing) conditions. We found that the competitive ability of P. aeruginosa strongly depended on the strain background of S. aureus, whereby P. aeruginosa dominated against Cowan I and 6850 but not against JE2. In the latter case, both species could end up as winners depending on conditions. Specifically, we observed strong frequency-dependent fitness patterns, including positive frequency dependence, where P. aeruginosa could dominate JE2 only when common (not when rare). Finally, changes in environmental (culturing) conditions fundamentally altered the competitive balance between the two species in a way that P. aeruginosa dominance increased when moving from shaken to static environments. Altogether, our results highlight that ecological details can have profound effects on the competitive dynamics between coinfecting pathogens and determine whether two species can coexist or invade each others’ populations from a state of rare frequency. Moreover, our findings might parallel certain dynamics observed in chronic polymicrobial infections. IMPORTANCE Bacterial infections are frequently caused by more than one species, and such polymicrobial infections are often considered more virulent and more difficult to treat than the respective monospecies infections. Pseudomonas aeruginosa and Staphylococcus aureus are among the most important pathogens in polymicrobial infections, and their cooccurrence is linked to worse disease outcome. There is great interest in understanding how these two species interact and what the consequences for the host are. While previous studies have mainly looked at molecular mechanisms implicated in interactions between P. aeruginosa and S. aureus, here we show that ecological factors, such as strain background, species frequency, and environmental conditions, are important elements determining population dynamics and species coexistence patterns. We propose that the uncovered principles also play major roles in infections and, therefore, proclaim that an integrative approach combining molecular and ecological aspects is required to fully understand polymicrobial infections.

scholarly journals Evolution of Bacterial “Frenemies”

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Sophie E. Darch ◽  
Carolyn B. Ibberson ◽  
Marvin Whiteley
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Community Assembly ◽  
Microbial Interactions ◽  
Microbial Interaction ◽  
Microbial Dynamics ◽  
Lung Infections ◽  
Insight Into ◽  
Polymicrobial Infections

ABSTRACT Chronic polymicrobial infections are associated with increased virulence compared to monospecies infections. However, our understanding of microbial dynamics during polymicrobial infection is limited. A recent study by Limoli and colleagues (D. H. Limoli, G. B. Whitfield, T. Kitao, M. L. Ivey, M. R. Davis, Jr., et al., mBio 8:e00186-17, 2017, https://doi.org/10.1128/mBio.00186-17 !) provides insight into a mechanism that may contribute to the coexistence of Pseudomonas aeruginosa and Staphylococcus aureus in the cystic fibrosis (CF) lung. CF lung infections have frequently been used to investigate microbial interactions due to both the complex polymicrobial community and chronic nature of these infections. The hypothesis of Limoli et al. is that the conversion of P. aeruginosa to its mucoidy phenotype during chronic CF infection promotes coexistence by diminishing its ability to kill S. aureus. Highlighting a new facet of microbial interaction between two species that are traditionally thought of as competitors, this study provides a platform for studying community assembly in a relevant infection setting.

scholarly journals Pseudomonas aeruginosa Alters Staphylococcus aureus Sensitivity to Vancomycin in a Biofilm Model of Cystic Fibrosis Infection

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Giulia Orazi ◽  
George A. O’Toole
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Protein Synthesis ◽  
Respiratory Pathogens ◽  
Interspecies Interactions ◽  
Protein Synthesis Inhibitors ◽  
Lung Infections ◽  
Polymicrobial Infections

ABSTRACT The airways of cystic fibrosis (CF) patients have thick mucus, which fosters chronic, polymicrobial infections. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients. In this study, we tested whether P. aeruginosa influences the susceptibility of S. aureus to frontline antibiotics used to treat CF lung infections. Using our in vitro coculture model, we observed that addition of P. aeruginosa supernatants to S. aureus biofilms grown either on epithelial cells or on plastic significantly decreased the susceptibility of S. aureus to vancomycin. Mutant analyses showed that 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), a component of the P. aeruginosa Pseudomonas quinolone signal (PQS) system, protects S. aureus from the antimicrobial activity of vancomycin. Similarly, the siderophores pyoverdine and pyochelin also contribute to the ability of P. aeruginosa to protect S. aureus from vancomycin, as did growth under anoxia. Under our experimental conditions, HQNO, P. aeruginosa supernatant, and growth under anoxia decreased S. aureus growth, likely explaining why this cell wall-targeting antibiotic is less effective. P. aeruginosa supernatant did not confer additional protection to slow-growing S. aureus small colony variants. Importantly, P. aeruginosa supernatant protects S. aureus from other inhibitors of cell wall synthesis as well as protein synthesis-targeting antibiotics in an HQNO- and siderophore-dependent manner. We propose a model whereby P. aeruginosa causes S. aureus to shift to fermentative growth when these organisms are grown in coculture, leading to reduction in S. aureus growth and decreased susceptibility to antibiotics targeting cell wall and protein synthesis. IMPORTANCE Cystic fibrosis (CF) lung infections are chronic and difficult to eradicate. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients and are associated with poor patient outcomes. Both organisms adopt a biofilm mode of growth, which contributes to high tolerance to antibiotic treatment and the recalcitrant nature of these infections. Here, we show that P. aeruginosa exoproducts decrease the sensitivity of S. aureus biofilm and planktonic populations to vancomycin, a frontline antibiotic used to treat methicillin-resistant S. aureus in CF patients. P. aeruginosa also protects S. aureus from other cell wall-active antibiotics as well as various classes of protein synthesis inhibitors. Thus, interspecies interactions can have dramatic and unexpected consequences on antibiotic sensitivity. This study underscores the potential impact of interspecies interactions on antibiotic efficacy in the context of complex, polymicrobial infections. IMPORTANCE Cystic fibrosis (CF) lung infections are chronic and difficult to eradicate. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients and are associated with poor patient outcomes. Both organisms adopt a biofilm mode of growth, which contributes to high tolerance to antibiotic treatment and the recalcitrant nature of these infections. Here, we show that P. aeruginosa exoproducts decrease the sensitivity of S. aureus biofilm and planktonic populations to vancomycin, a frontline antibiotic used to treat methicillin-resistant S. aureus in CF patients. P. aeruginosa also protects S. aureus from other cell wall-active antibiotics as well as various classes of protein synthesis inhibitors. Thus, interspecies interactions can have dramatic and unexpected consequences on antibiotic sensitivity. This study underscores the potential impact of interspecies interactions on antibiotic efficacy in the context of complex, polymicrobial infections.

scholarly journals Controlling Staphylococcus aureus by 2-[(Methylamino)methyl]phenol (2-MAMP) in a co-culture moderates the biofilm and virulence of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Gopalakrishan Thamil Selvan ◽  
Brindha Thirunavukkarasu ◽  
Nerellapalli Nandini Pravallika ◽  
Sahana Vasudevan ◽  
Balamurugan Palaniappan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Chronic Wound ◽  
Healing Process ◽  
Relative Increase ◽  
Polymicrobial Infection ◽  
Wound Healing Process ◽  
Polymicrobial Infections ◽  
Chronic Wound Infection

Staphylococcus aureus and Pseudomonas aeruginosa are the most encountered organisms in a polymicrobial chronic wound infection. Production of multiple virulence factors by this duo delays wound healing process. Notably P. aeruginosa displays enhanced virulence in the presence of S. aureus by a peptidoglycan sensing mechanism. Thus novel therapies are imperative to address polymicrobial infections effectively. Previously, it has been suggested that targeting S. aureus might be a possible approach to reduce the severity of P. aeruginosa in a polymicrobial infection. In this aspect, we have used 2-[(Methylamino)methyl]phenol (2-MAMP), our previously reported QS inhibitor to target S. aureus and phenotypically determine the virulence factors of P. aeruginosa under this condition. Analysis of major virulence factors of Pseudomonas viz. biofilm, pyocyanin and pyoveridine showed a significant reduction. The competitive index (CI) and relative increase ratio (RIR) were determined to understand the organisms interaction in co-culture. Results indicated competitiveness among the strains and on increasing ratios of S. aureus cells, co-existence was noticed. Further as a sensible approach antibiotic anti-virulence drug combinations were tested on co-culture. Significant improvement in the growth inhibition was observed. Our preliminary results presented here would enable further research to address polymicrobial infection in a novel way.

scholarly journals Iron Depletion Enhances Production of Antimicrobials by Pseudomonas aeruginosa

2015 ◽  
Vol 197 (14) ◽  
pp. 2265-2275 ◽  
Author(s):  
Angela T. Nguyen ◽  
Jace W. Jones ◽  
Max A. Ruge ◽  
Maureen A. Kane ◽  
Amanda G. Oglesby-Sherrouse
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Iron Depletion ◽  
Content Type ◽  
Regulatory Pathways ◽  
Enhanced Production ◽  
Antimicrobial Metabolites ◽  
Polymicrobial Infections

ABSTRACTCystic fibrosis (CF) is a heritable disease characterized by chronic, polymicrobial lung infections. WhileStaphylococcus aureusis the dominant lung pathogen in young CF patients,Pseudomonas aeruginosabecomes predominant by adulthood.P. aeruginosaproduces a variety of antimicrobials that likely contribute to this shift in microbial populations. In particular, secretion of 2-alkyl-4(1H)-quinolones (AQs) contributes to lysis ofS. aureusin coculture, providing an iron source toP. aeruginosabothin vitroandin vivo. We previously showed that production of one such AQ, thePseudomonasquinolone signal (PQS), is enhanced by iron depletion and that this induction is dependent upon the iron-responsive PrrF small RNAs (sRNAs). Here, we demonstrate that antimicrobial activity againstS. aureusduring coculture is also enhanced by iron depletion, and we provide evidence that multiple AQs contribute to this activity. Strikingly, aP. aeruginosaΔprrFmutant, which produces very little PQS in monoculture, was capable of mediating iron-regulated growth suppression ofS. aureus. We show that the presence ofS. aureussuppresses the ΔprrF1,2mutant's defect in iron-regulated PQS production, indicating that a PrrF-independent iron regulatory pathway mediates AQ production in coculture. We further demonstrate that iron-regulated antimicrobial production is conserved in multipleP. aeruginosastrains, including clinical isolates from CF patients. These results demonstrate that iron plays a central role in modulating interactions ofP. aeruginosawithS. aureus. Moreover, our studies suggest that established iron regulatory pathways of these pathogens are significantly altered during polymicrobial infections.IMPORTANCEChronic polymicrobial infections involvingPseudomonas aeruginosaandStaphylococcus aureusare a significant cause of morbidity and mortality, as the interplay between these two organisms exacerbates infection. This is in part due to enhanced production of antimicrobial metabolites byP. aeruginosawhen these two species are cocultured. Using both established and newly developed coculture techniques, this report demonstrates that iron depletion increasesP. aeruginosa's ability to suppress growth ofS. aureus. These findings present a novel role for iron in modulating microbial interaction and provide the basis for understanding how essential nutrients drive polymicrobial infections.

Sign in / Sign up

Export Citation Format

Share Document