Study of pyoverdine type and production by Pseudomonas aeruginosa isolated from cystic fibrosis patients: prevalence of type II pyoverdine isolates and accumulation of pyoverdine-negative mutations

Vos, Daniël De; Chial, Magali De; Cochez, Christel; Jansen, Silke; Tümmler, Burkhard; Meyer, Jean Marie; Cornélis, Pierre

doi:10.1007/s002030100278

Cited by 167 publications

(162 citation statements)

References 16 publications

(28 reference statements)

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“…Consequently, in mixed populations where both wild-type and mutant bacteria are present, the mutants can gain the benefit of siderophore production without paying the cost and hence increase in frequency, as they outcompete the cooperative wild type (Griffin et al, 2004). Consistent with the above in vitro results, siderophore-negative cheats have been observed in natural populations of P. aeruginosa that have infected the lungs of cystic fibrosis patients (de Vos et al, 2001).…”

Section: Public Goods Cooperationsupporting

confidence: 68%

Kin selection and the evolution of virulence

2008

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Social interactions between conspecific parasites are partly dependent on the relatedness of interacting parasites (kin selection), which, in turn, is predicted to affect the extent of damage they cause their hosts (virulence). High relatedness is generally assumed to favour less competitive interactions, but the relationship between relatedness and virulence is crucially dependent on the social behaviour in question. Here, we discuss the rather limited body of experimental work that addresses how kin-selected social behaviours affect virulence. First, if prudent use of host resources (a form of cooperation) maximizes the transmission success of the parasite population, decreased relatedness is predicted to result in increased host exploitation and virulence. Experimental support for this well-established theoretical result is surprisingly limited. Second, if parasite within-host growth rate is a positive function of cooperation (that is, when individuals need to donate public goods, such as extracellular enzymes), virulence is predicted to increase with increasing relatedness. The limited studies testing this hypothesis are broadly consistent with this prediction. Finally, there is some empirical evidence supporting theory that suggests that spiteful behaviours are maximized at intermediate degrees of relatedness, which, in turn, leads to minimal virulence because of the reduced growth rate of the infecting population. We highlight the need for further thorough experimentation on the role of kin selection in the evolution of virulence and identify additional biological complexities to these simple frameworks.

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Section: Public Goods Cooperationsupporting

confidence: 68%

Kin selection and the evolution of virulence

2008

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“…However, our simulations also show that the relative prevalence of strains producing both siderophores can decrease when the environment is less prone to change and/or is biased towards some specific conditions. Just such a scenario may apply during chronic infections in cystic fibrosis lungs, where pyoverdine-negative mutants typically accumulate over time [56][57][58]. One possible explanation for this observation is that siderophores are not required in the lung because iron concentration is increased (7.5 -33 mM; [59,60]).…”

Section: Discussionmentioning

confidence: 99%

Switching between apparently redundant iron-uptake mechanisms benefits bacteria in changeable environments

2013

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Bacteria often possess multiple siderophore-based iron uptake systems for scavenging this vital resource from their environment. However, some siderophores seem redundant, because they have limited iron-binding efficiency and are seldom expressed under iron limitation. Here, we investigate the conundrum of why selection does not eliminate this apparent redundancy. We focus on Pseudomonas aeruginosa, a bacterium that can produce two siderophores-the highly efficient but metabolically expensive pyoverdine, and the inefficient but metabolically cheap pyochelin. We found that the bacteria possess molecular mechanisms to phenotypically switch from mainly producing pyoverdine under severe iron limitation to mainly producing pyochelin when iron is only moderately limited. We further show that strains exclusively producing pyochelin grew significantly better than strains exclusively producing pyoverdine under moderate iron limitation, whereas the inverse was seen under severe iron limitation. This suggests that pyochelin is not redundant, but that switching between siderophore strategies might be beneficial to trade off efficiencies versus costs of siderophores. Indeed, simulations parameterized from our data confirmed that strains retaining the capacity to switch between siderophores significantly outcompeted strains defective for one or the other siderophore under fluctuating iron availabilities. Finally, we discuss how siderophore switching can be viewed as a form of collective decision-making, whereby a coordinated shift in behaviour at the group level emerges as a result of positive and negative feedback loops operating among individuals at the local scale.

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“…Studies involving transcriptomic and proteomic data from clinical clonal isolates, real-time quantitative PCR of CF sputa and sequence analysis of target genes in co-culture systems have yielded insights into how these pathogens, particularly P. aeruginosa, behave in the clinical context. In two separate studies of chronic isolates from CF patients, P. aeruginosa lost the ability to make pyoverdine, but retained the ability to take up ferripyoverdine (De Vos et al, 2001;Smith et al, 2006). A review by Lamont et al (2009) describes the multifaceted and adaptive nature of iron acquisition by P. aeruginosa in the CF lung.…”

Section: Pathogen Interactions and Competition For Iron In Cfmentioning

confidence: 99%

Iron acquisition in the cystic fibrosis lung and potential for novel therapeutic strategies

Tyrrell¹,

Callaghan²

2016

Microbiology

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Iron acquisition is vital to microbial survival and is implicated in the virulence of many of the pathogens that reside in the cystic fibrosis (CF) lung. The multifaceted nature of iron acquisition by both bacterial and fungal pathogens encompasses a range of conserved and speciesspecific mechanisms, including secretion of iron-binding siderophores, utilization of siderophores from other species, release of iron from host iron-binding proteins and haemoproteins, and ferrous iron uptake. Pathogens adapt and deploy specific systems depending on iron availability, bioavailability of the iron pool, stage of infection and presence of competing pathogens. Understanding the dynamics of pathogen iron acquisition has the potential to unveil new avenues for therapeutic intervention to treat both acute and chronic CF infections. Here, we examine the range of strategies utilized by the primary CF pathogens to acquire iron and discuss the different approaches to targeting iron acquisition systems as an antimicrobial strategy.

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Study of pyoverdine type and production by Pseudomonas aeruginosa isolated from cystic fibrosis patients: prevalence of type II pyoverdine isolates and accumulation of pyoverdine-negative mutations

Cited by 167 publications

References 16 publications

Kin selection and the evolution of virulence

Kin selection and the evolution of virulence

Switching between apparently redundant iron-uptake mechanisms benefits bacteria in changeable environments

Iron acquisition in the cystic fibrosis lung and potential for novel therapeutic strategies

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