Competition, coinfection and strain replacement in models of Bordetella pertussis

Nicoli, Emily; Ayabina, Diepreye; Trotter, Caroline; Turner, Katherine Mary Elizabeth; Colijn, Caroline

doi:10.1016/j.tpb.2015.05.003

Cited by 12 publications

(7 citation statements)

References 38 publications

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“…In other pathogen systems, the role of neutral vs. non-neutral forces were also investigated, which revealed unforeseen patterns. For example, Nicoli et al 42 found that strain replacement is more likely under generalized immunity than strain-specific immunity when vaccination is applied in Pertussis. Cobey and Lipsitch 43 demonstrated that weak specific immunity together with generalized immunity permit the coexistence of strains with weak competence in Streptococcus pneumoniae .…”

Section: Discussionmentioning

confidence: 99%

Networks of genetic similarity reveal non-neutral processes shape strain structure in Plasmodium falciparum

et al. 2018

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Pathogens compete for hosts through patterns of cross-protection conferred by immune responses to antigens. In Plasmodium falciparum malaria, the var multigene family encoding for the major blood-stage antigen PfEMP1 has evolved enormous genetic diversity through ectopic recombination and mutation. With 50–60 var genes per genome, it is unclear whether immune selection can act as a dominant force in structuring var repertoires of local populations. The combinatorial complexity of the var system remains beyond the reach of existing strain theory and previous evidence for non-random structure cannot demonstrate immune selection without comparison with neutral models. We develop two neutral models that encompass malaria epidemiology but exclude competitive interactions between parasites. These models, combined with networks of genetic similarity, reveal non-neutral strain structure in both simulated systems and an extensively sampled population in Ghana. The unique population structure we identify underlies the large transmission reservoir characteristic of highly endemic regions in Africa.

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Section: Discussionmentioning

confidence: 99%

Networks of genetic similarity reveal non-neutral processes shape strain structure in Plasmodium falciparum

et al. 2018

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“…This is at one end of a spectrum, and modellers do not choose to model transmission of these infections simultaneously (precisely because they would not affect each other). However, low values of c are implicitly assumed by models (of the same infection with different strains, e.g., resistant and sensitive) that do not take competition into account, for example, by including co-infection in a way that dramatically reduces competition (see also the discussion in Nicoli et al (2015) ). The final model in (2) contains, in the first equation of (2), terms for: entry from susceptibles into X ( F x S ), re-infection of X with the Y strain ( κF y X ), re-entry to X from duals re-infected with

, clearance of X ( u x X ), clearance of the Y strain in duals (1 − c ) u y D , and acquisition of resistance plus competitive release of resistance due to treatment ( μ + Tr ) X .…”

Section: Between-host Model: Two Ends Of a Continuummentioning

confidence: 99%

Section: Between-host Model: Two Ends Of a Continuummentioning

confidence: 99%

How competition governs whether moderate or aggressive treatment minimizes antibiotic resistance

Colijn

Cohen

2015

eLife

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Understanding how our use of antimicrobial drugs shapes future levels of drug resistance is crucial. Recently, there has been debate over whether an aggressive (i.e., high dose) or more moderate (i.e., lower dose) treatment of individuals will most limit the emergence and spread of resistant bacteria. In this study, we demonstrate how one can understand and resolve these apparently contradictory conclusions. We show that a key determinant of which treatment strategy will perform best at the individual level is the extent of effective competition between resistant and sensitive pathogens within a host. We extend our analysis to the community level, exploring the spectrum between strict inter-strain competition and strain independence. From this perspective as well, we find that the magnitude of effective competition between resistant and sensitive strains determines whether an aggressive approach or moderate approach minimizes the burden of resistance in the population.DOI: http://dx.doi.org/10.7554/eLife.10559.001

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“…The main driving force for this strain evolution is thought to be immune pressure from vaccination, with emergence of ‘vaccine escape’ mutants [38,39]. A study by Preston’s group on strains from a 2012 outbreak in the UK and other strains from additional outbreaks globally found that acellular vaccine antigen-encoding genes [pertussis toxin ( ptx ), pertactin ( prn ), Fha ( fha ), and Fim ( fim )] are evolving at a significantly higher rate than genes encoding other surface antigens not included in the vaccine [40 ▪▪ ].…”

Section: Emergence Of B Pertussis Strains With Increased Virulence?mentioning

confidence: 99%

Bordetella pertussis

Carbonetti

2016

Current Opinion in Infectious Diseases

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Purpose of review The purpose of this review is to summarize and discuss recent findings and selected topics of interest in Bordetella pertussis virulence and pathogenesis and treatment of pertussis. It is not intended to cover issues on immune responses to B. pertussis infection or problems with currently used pertussis vaccines. Recent findings Studies on the activities of various B. pertussis virulence factors include the immunomodulatory activities of filamentous hemagglutinin, fimbriae, and adenylate cyclase toxin. Recently emerging B. pertussis strains show evidence of genetic selection for vaccine escape mutants, with changes in vaccine antigen-expressing genes, some of which may have increased the virulence of this pathogen. Severe and fatal pertussis in young infants continues to be a problem, with several studies highlighting predictors of fatality, including the extreme leukocytosis associated with this infection. Treatments for pertussis are extremely limited, though early antibiotic intervention may be beneficial. Neutralizing pertussis toxin activity may be an effective strategy, as well as targeting two host proteins, pendrin and sphingosine-1-phosphate receptors, as novel potential therapeutic interventions. Summary Pertussis is reemerging as a major public health problem and continued basic research is revealing information on bacterial virulence and disease pathogenesis, as well as potential novel strategies for vaccination and targets for therapeutic intervention.

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Competition, coinfection and strain replacement in models of Bordetella pertussis

Cited by 12 publications

References 38 publications

Networks of genetic similarity reveal non-neutral processes shape strain structure in Plasmodium falciparum

Networks of genetic similarity reveal non-neutral processes shape strain structure in Plasmodium falciparum

How competition governs whether moderate or aggressive treatment minimizes antibiotic resistance

Bordetella pertussis

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