• Although virulence is typically attributed to single pathogenic strains, here we investigated whether effectors secreted by a population of non-virulent strains could function as public goods to enable the emergence of collective virulence. (nature.com)
  • The ability of Listeria monocytogenes isolates to survive within the food production environment (FPE), as well as virulence, varies greatly between strains. (northumbria.ac.uk)
  • In this study, we assessed the FPE fitness and virulence potential, including efficacy of selected hygiene or treatment intervention, against 52 L. monocytogenes strains isolated from various food and food environment sources. (northumbria.ac.uk)
  • Pathogen strains that kill the host can increase in virulence as long as the pathogen can transmit itself to a new host, whether before or after the host dies. (wikipedia.org)
  • In Chile, although a sustained increase in CR- Kp infections has been observed, few strains have been described at the genomic level, lacking molecular details of their resistance and virulence determinants and the mobile elements mediating their dissemination. (biorxiv.org)
  • The results consistently showed that strains unable to metabolize proline exhibit significantly reduced virulence properties and a clearly diminished capacity to undergo morphological transitions. (sciencedaily.com)
  • A comparison of four virulent Y. pestis strains with the human-avirulent strain 91001 provides further insight into the genetic basis of virulence to humans. (asm.org)
  • These OsR strains retain virulence, replicative fitness and transmissibility from person to person, with outbreaks reported. (eurekaselect.com)
  • Colonial sizes of the two strains do not reveal any significant differences in growth fitness of the strains. (scirp.org)
  • Furthermore, the extrachromosomal elements bearing the mucoid phenotype and the resistance elements in the mucoid strains do not significantly impact on the fitness of the cognate strain. (scirp.org)
  • 10 However, VGI is an emerging and more abundant molecular type in Asia, Australia, and Europe 11 , and some studies showed obvious differences in virulence among individual VGI strains. (researchsquare.com)
  • In this study, we aimed to answer whether C gattii VGI could be genetically categorized into subgroups, hoping to explain difference in virulence among individual VGI strains. (researchsquare.com)
  • In addition to multi-omics (WGS and RNA-Seq) experiments, we also performed in vitro and in vivo evaluation to characterize the virulence trait of divergent molecular subtypes of C gattii VGI strains. (researchsquare.com)
  • Using isoallelic mutant strains, we found that 3 polymorphisms in this toxin gene region increase resistance to killing by human polymorphonuclear leukocytes, increase bacterial proliferation, and increase virulence in animal models of pharyngitis and necrotizing fasciitis. (jci.org)
  • Genome sequencing of an additional 1,125 streptococcal strains and virulence studies revealed that a highly similar recombinational replacement event underlies an ongoing intercontinental epidemic of serotype M89 group A Streptococcus infections. (jci.org)
  • A genomic analysis was also performed to identify resistance genes correlating to the observed phenotypic resistance profiles, along with genetic determinants of interest which may elude to the FPE fitness and virulence potential. (northumbria.ac.uk)
  • These results provide baseline knowledge for the detailed understanding of molecular and genetic determinants behind antibiotic resistance and virulence of K. pneumoniae in Chile and South America. (biorxiv.org)
  • Viral determinants that drive Enterovirus-A71 fitness and virulence. (nih.gov)
  • Klebsiella pneumoniae is an opportunistic pathogen of medical importance and the capsule and mucoid phenotype in this organism are considered as requisite virulence determinants. (scirp.org)
  • Any movement on the virulence axis, towards higher or lower virulence, will result in lower fitness for the parasite, and thus will be selected against. (wikipedia.org)
  • In particular, it has been claimed that the evolution of lower virulence in response to limited parasite dispersal. (scienceblogs.com)
  • However, despite abundant evidence that effects of stressors can carry across generations, studies of pathogen virulence have focused almost exclusively on a single generation. (researchgate.net)
  • Experimental manipulation of population-level MHC diversity controls pathogen virulence evolution in Mus musculus. (utah.edu)
  • We report here that myricetin, but not its glycosylated form, can remarkably decrease the production of several S. aureus virulence factors, including adhesion, biofilm formation, hemolysis and staphyloxanthin production, without interfering with growth. (nature.com)
  • In this study, we present a novel transcriptional regulator, PA1226, which modulates biofilm formation and virulence in P. aeruginosa. (diagenode.com)
  • Pneumonia isolates carried higher proportions of virulence genes sfa/foc , papGIII , hlyC , cnf1 , and iroN compared with bacteremia isolates. (cdc.gov)
  • Of note, the genes encoding these effectors and immunity proteins are widely distributed in Salmonella genomes, suggesting a relevant role in interbacterial competition and virulence. (frontiersin.org)
  • Transcriptome analysis revealed that PA1226 regulates many essential virulence genes/pathways, including those involved in alginate, pili, and LPS biosynthesis. (diagenode.com)
  • Genetic and molecular analyses have led to the identification, cloning and characterization of a few genes that contribute to parasitic fitness in the pathogens. (sisef.it)
  • The ongoing annotation of these genomes should spark a new wave of interest in the DED pathosystem, as it should lead to the formal identification of genes modulating parasitic fitness. (sisef.it)
  • With the help of high-throughput transposon sequencing (TnSeq), the researchers searched for fitness contributors in the mutant K1 strain Escherichia coli in a mouse model of neonatal meningitis, focusing on possible vaccine candidate genes related to brain infection or systemic dissemination of the bacterial meningitis bug. (genomeweb.com)
  • In other bacterial pathogens, genes important for pathogenicity and host range include secreted protein effectors that suppress host immunity, alter host metabolism, and enable colonization, providing a fitness advantage. (biorxiv.org)
  • Functional experiments revealed that certain positively selected genes might enhance mammalian virulence by interacting with host cellular pathways or utilizing host nutrients . (bvsalud.org)
  • Analysis of virulence related gene expression and computational simulations of pivotal proteins involved in pathogenesis demonstrate that myricetin downregulates the saeR global regulator and interacts with sortase A and α-hemolysin. (nature.com)
  • This regulator is also essential for the in vivo fitness and pathogenesis in both Drosophila melanogaster and BALB/c mouse lung infection models. (diagenode.com)
  • Urease is a metalloenzyme known to play a crucial role in the pathogenesis and virulence of catheter-associated Proteus mirabilis infection. (lancs.ac.uk)
  • These findings improve our understanding of the pathogenesis of melioidosis , and establish Bp as a model system for studying the genetics of accidental virulence . (bvsalud.org)
  • Interestingly, while both systems have been linked to virulence and host colonization in S . Dublin, an antibacterial activity has not been detected for T6SS SPI-6 in this serotype. (frontiersin.org)
  • Virulence factor gene content and antimicrobial drug resistance were higher in pneumonia than in commensal isolates. (cdc.gov)
  • These high-risk pathogens have developed mainly by acquiring different mobile genetic elements (MGEs), including plasmids and genomic islands (GIs) encoding an array of virulence and antibiotic resistance factors[ 2 ]. (biorxiv.org)
  • Here, we identify a critical role of PerR-regulated gene expression in GAS phagocytosis resistance and in virulence during pharyngeal infection. (harvard.edu)
  • This finding suggests a novel role for PerR in mediating sugar uptake and utilization that, together with phagocytic killing resistance, may contribute to GAS fitness in the infected host. (harvard.edu)
  • By identifying the molecular changes that enhance upper respiratory tract fitness, increased resistance to innate immunity, and increased tissue destruction, we describe a mechanism that underpins epidemic streptococcal infections, which have affected many millions of people. (jci.org)
  • Targeting urease as a therapeutic candidate facilitates the disarming of bacterial virulence without affecting bacterial fitness, thereby limiting the selective pressure placed on the invading population and lowering the rate at which it will acquire resistance. (lancs.ac.uk)
  • Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. (preprints.org)
  • We conducted in planta infection studies and uncovered an unexpected non-monotonic relationship between growth rate and virulence that is jointly shaped by how growth rate and metabolic efficiency interact. (exeter.ac.uk)
  • To study the role of PGdx in virulence and to assess the requirement of H 2 O 2 -scavenging during the course of infection, both a pgdx single mutant and a pgdx / hktE double mutant of Hib were assayed for virulence in an infant rat model. (biomedcentral.com)
  • Finally, H 2 O 2 -scavenging is not a determinant of Hib virulence in the infant rat model of infection. (biomedcentral.com)
  • This finding has raised an intriguing question: Does C. jejuni sense, inject and secrete putative virulence factors into host cells? (assignster.com)
  • Secretion systems, and the diverse proteins that they secrete, represent key virulence factors against eukaryotic host organisms. (dundee.ac.uk)
  • Finally, we tested whether aphid genetics can be used to further dissect the genetic mechanisms of biotype virulence in aphids. (usda.gov)
  • Genome sequencing on C gattii in recent years has become a powerful tool to reveal novel lineages as well as genetic variations that were associated with phenotypes and virulence in different lineages and/or subtypes within the same lineage. (researchsquare.com)
  • Whether these phenotype and resistances that had no fitness cost to the bacterium could significantly affect the virulence of the bacteria in vivo remains to be investigated. (scirp.org)
  • The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. (preprints.org)
  • The evolution of virulence in pathogens is a balance between the costs and benefits of virulence to the pathogen. (wikipedia.org)
  • An interesting exchange in Nature on ways to conceptualize the evolution of virulence. (scienceblogs.com)
  • First, Adaptation and the evolution of parasite virulence in a connected world: Adaptation is conventionally regarded as occurring at the level of the individual organism, where it functions to maximize the individual's inclusive fitness. (scienceblogs.com)
  • However, it has recently been argued that empirical studies on the evolution of parasite virulence in spatial populations show otherwise. (scienceblogs.com)
  • This novel mechanistic framework paves the way for a much-needed new suite of virulence evolution theories. (exeter.ac.uk)
  • A genomic survey of positive selection in Burkholderia pseudomallei provides insights into the evolution of accidental virulence. (bvsalud.org)
  • As it battles to overcome the effects of the drug, the fungus becomes weaker, with a reduction in the traits associated with virulence. (sciencedaily.com)
  • However, the geographical distribution, molecular traits, and virulence difference are poorly characterized in China. (researchsquare.com)
  • Proteins from the bacterial endosymbiont of aphids were also differentially expressed in biotype H. Guided by the proteome results, we tested whether biotype H had a fitness advantage compared to other S. graminum biotypes and found that biotype H had a higher reproductive fitness as compared to two other biotypes on a range of different wheat germplasms. (usda.gov)
  • Mouse fitness measures reveal incomplete functional redundancy of Hox paralogous group 1 proteins. (utah.edu)
  • The Type VI Secretion System (T6SS) is a multiprotein device that has emerged as an important fitness and virulence factor for many Gram-negative bacteria through the injection of effector proteins into prokaryotic or eukaryotic cells via a contractile mechanism. (frontiersin.org)
  • Each coisogenic strain was individually unfit, but the metaclone was collectively as virulent as the wild-type strain on Arabidopsis thaliana , suggesting that effectors can drive the emergence of cooperation-based virulence through their public action. (nature.com)
  • Fig. 1: Metaclones of P. syringae facilitate the emergence of population virulence. (nature.com)
  • The identification of the molecular events responsible for strain emergence, enhanced virulence, and epidemicity has been a long-pursued goal in infectious diseases research. (jci.org)
  • The same mutations that enhance the reproduction and dispersal of the pathogen also enhance its virulence in the host, causing much harm (disease and death). (wikipedia.org)
  • Viruses carrying the H4-HA with or without R327 or K327 mutations and the other gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. (preprints.org)
  • In this study, we used comparative proteomics to identify protein expression differences associated with virulence. (usda.gov)
  • The parasite's fitness is determined by its success in transmitting offspring to other hosts. (wikipedia.org)
  • Evolutionary modifications improving Bp environmental fitness may thus have indirectly facilitated the ability of Bp to colonize and survive in mammalian hosts. (bvsalud.org)
  • A Cost of Sexual Attractiveness to High-Fitness Females: Adaptive mate choice by females is an important component of sexual selection in many species. (scienceblogs.com)
  • Surprisingly, a large proportion of these loci are involved in sugar utilization and transport, in addition to oxidative stress adaptive responses and virulence. (harvard.edu)
  • In a prospective, nationwide study in France of Escherichia coli responsible for pneumonia in patients receiving mechanical ventilation, we determined E. coli antimicrobial susceptibility, phylotype, O-type, and virulence factor gene content. (cdc.gov)
  • More commonly, however, the target is rival bacterial cells, making the T6SS a key player in inter-bacterial competition and competitive fitness, and therefore an indirect virulence factor. (dundee.ac.uk)
  • From there, they performed a series of follow-up analyses on one of these candidates - a surface polysaccharide known as poly-beta-(1,6)-N-acetyl glucosamine, or PNAG - demonstrating that the virulence factor may be vulnerable to vaccine targeting in E. coli K1 and in Group B Streptococcus that can also cause neonatal meningitis. (genomeweb.com)
  • This might induce faster host death, and act against the parasite's fitness by reducing probability to encounter another host (killing the host too fast to allow for transmission). (wikipedia.org)
  • Paul W. Ewald has explored the relationship between virulence and mode of transmission. (wikipedia.org)
  • Ewald is convinced that the crowding of field hospitals and trench warfare provided an easy route to transmission that evolved the virulence of the 1918 influenza pandemic. (wikipedia.org)
  • For example, studies of the malaria parasite using rodent and chicken models found that there was trade-off between transmission success and virulence as defined by host mortality. (wikipedia.org)
  • Mechanisms of virulence on the aphid side of the plant-insect interaction are not well understood. (usda.gov)
  • My current research is examining nutrient acquisition by fungi, how feeding mechanisms evolve and how external digestion can influence the fitness of a pathogen population and the damage that they cause to plants. (exeter.ac.uk)
  • However, Haemophilus influenzae type b strain Eagan (Hib), a causative agent of bacterial sepsis and meningitis in young children, disrupted in its hktE gene is not attenuated in virulence, and retains the ability to rapidly scavenge H 2 O 2 . (biomedcentral.com)
  • At one time, some biologists argued that pathogens would tend to evolve toward ever decreasing virulence because the death of the host (or even serious disability) is ultimately harmful to the pathogen living inside. (wikipedia.org)
  • Pathogenicity and Virulence of Ebolaviruses with Species- and Variant-specificity. (cdc.gov)
  • Unlike antibacterials that aim to inhibit cell growth, antivirulence therapies are based on the inhibition of bacterial virulence. (nature.com)
  • Comparative analysis of Protein Kinase A homologues in the growth and virulence of Aspergillus fumigatus. (academictree.org)
  • Metabolic efficiency reshapes the seminal relationship between pathogen growth rate and virulence. (exeter.ac.uk)
  • In this paper, we identify a key component missing from current theories which redefines the growth-virulence relationship in a way that is consistent with data. (exeter.ac.uk)
  • This characteristic makes biotype H ideal for comparative proteomics to investigate the basis of biotype virulence in aphids. (usda.gov)