Immune-mediated competition benefits protective microbes over pathogens in a novel host species
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Abstract Microbes that protect against infection inhabit hosts across the tree of life. It is unclear whether and how the host immune system may affect the formation of new protective symbioses. We investigated the transcriptomic response of Caenorhabditis elegans following novel interactions with a protective microbe ( Enterococcus faecalis ) able to defend against infection by pathogenic Staphylococcus aureus . We have previously shown that E. faecalis can directly limit pathogen growth within hosts. In this study, we show that colonisation by protective E. faecalis caused the differential expression of 1,557 genes in pathogen infected hosts, including the upregulation of immune genes such as lysozymes and C-type lectins. The most significantly upregulated host lysozyme gene, lys-7, impacted the competitive abilities of E. faecalis and S. aureus when knocked out. E. faecalis has an increased ability to resist lysozyme activity compared to S. aureus , suggesting that the protective microbe could gain a competitive advantage from this host response. Our finding that protective microbes can benefit from immune-mediated competition after introduction opens up new possibilities for biocontrol design and our understanding of symbiosis evolution. Crosstalk between the host immune response and microbe-mediated protection should favour the continued investment in host immunity and avoid the potentially risky evolution of host dependence.Keywords:
Enterococcus faecalis
AbstractIn multihost-multipathogen communities, a focal host's risk of being infected by a particular pathogen can be influenced by the presence of other host and pathogen species. We explore how indirect interactions between pathogens at the within-host level (through coinfecting the same individual) and the between-host level (through altered susceptible host densities) affect the focal host's risk of infection. We use an SI-type epidemiological model of two host species and two environmentally transmitted pathogens where one pathogen is a specialist on the focal host and the other pathogen is a generalist. We show that monotonic, unimodal, and U-shaped relationships between the specialist and generalist infectious propagule densities (proxies of the focal host's risk of infection) are driven by the way within-host priority effects alter the production of specialist infectious propagules by infected focal host individuals. Interestingly, within-host priority effects can also lead to overcompensation in density wherein increased infected host mortality results in greater specialist infectious propagule density. We interpret these results in terms of how the focal host's risk of being infected by a specialist pathogen is affected by the presence of a generalist pathogen, its alternative host, and within-host priority effects.
Propagule
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Abstract In addition to their lethal effects, pathogens can cause a number of other debilitating effects on infected hosts. A population dynamical model of the interaction between an invertebrate host and a pathogen is constructed to examine the importance of one such debilitating effect on the host population dynamics. Specifically the feeding rate and therefore the uptake of pathogen free‐living infective particles by infected individuals is reduced as a consequence of the pathogen infection. The pathogen is more likely to regulate the host and the equilibrium population density of the host is reduced. Less intuitively there is also an increased chance of the pathogen causing cyclic population dynamics in the host.
Susceptible individual
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Background: The presence of persistent infections in the root canals by microorganisms causes root canal failure. The most commonly found bacteria that cause persistent infection is Enterococcus faecalis. PDI / photodynamic inactivation is an in vitro approach to inactivation of microorganisms. The combination of light and photosensitivity of chlorophyll in PDI will cause photoinactivation in bacteria. Long radiation of PDT can affect the production of singlet oxygen and ROS (Reactive Oxygen Species) to kill Enterococcus faecalis bacteria. Objective: To prove the effect of 405 nm laser diode with and without chlorophyll photosensitizer and the irradiation effect of 405 nm laser diode on the number of CFU of Enterococcus faecalis bacteria. Method: This study used the Enterococcus faecalis bacteria cultur which was divided into 5 groups. Group I as control group, Group II irradiation 30 ', III chlorophyll + irradiation 30', IV irradiation 60 ', V chlorophyll + irradiation 60'. After incubation, the bacteria count was calculated with Quebec Colony Counter and analyzed by Shapiro-Wilk test, Levene test and Anova test. Results: There were significant differences (p <0.05) between the number of colonies of Enterococcus faecalis bacteria in each treatment group. Longer duration of PDT exposure (Group II and IV) with chlorophyll showed less number of Enterococcus faecalis bacteria. Conclusion: The longer the PDT irradiation, the less number of Enterococcus faecalis bacteria. The 60-second radiation with chlorophyll showed the least amount of Enterococcus faecalis bacteria.
Enterococcus faecalis
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Enterococcus faecalis is the main pathogen detached from failed root canals and insistent peri-apical lesion. It founds in anatomical structures that remain inside inaccessible areas for mechanical instrumentation like lateral canal and isthmus so, the root canal irrigation has an important role in the elimination of microbes in these inaccessible areas for instrumentation. Aim of the study is to compare between the efficiency of a newly introduced product of chlorhexidine gluconate as chemical root canal irrigant and hydroalcoholic extract of garlic herbal product against Enterococcus faecalis. This study was In-vitro used the agar diffusion method. Enterococcus faecalis was cultured on blood agar plate. Thirty three plates were divided into two group Positive and negative control used for verification of the results. Chlorhexidine used as a positive control since it is the commonly used irrigate. The zone of inhibition measured and expressed in millimeters. The results of antibacterial activity were expressed in terms of the diameter of the zone of inhibition. Statistical package for social sciences (SPSS) was used to analyze the data. A descriptive statistics calculated the efficiency of the irrigation solution against Enterococcus faecalis. Student’s T-Test was used. The efficacy of chlorhexidine gluconate was found to be significantly more (18.31±0.946) than Garlic extract (14.71±0.985) against Enterococcus faecalis and the difference was statistically significant p<0.05. 2% chlorhexidine gluconate was shown to inhibit the Enterococcus faecalis effectively. But garlic extract (allicin) as compare to chlorhexidine showed very minimal activity against E. faecalis.
Enterococcus faecalis
Disinfectant
Chlorhexidine gluconate
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Significance Patterns of host breadth evolution in pathogens that attack multiple host species have seldom been quantified. Previous investigations of pathogens attacking a single host indicate that pathogen genotypes evolve a broad host range across host genotypes. By contrast, this investigation demonstrates that, in a pathogen attacking several host species, pathogen genotypes evolve to be highly host-specific. This difference suggests that the evolutionary dynamics of pathogen host breadth may differ depending on whether the pathogen attacks only one or multiple host species.
Host–pathogen interaction
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Abstract Multiple laboratory studies have evolved hosts against a nonevolving pathogen to address questions about evolution of immune responses. However, an ecologically more relevant scenario is one where hosts and pathogens can coevolve. Such coevolution between the antagonists, depending on the mutual selection pressure and additive variance in the respective populations, can potentially lead to a different pattern of evolution in the hosts compared to a situation where the host evolves against a nonevolving pathogen. In the present study, we used Drosophila melanogaster as the host and Pseudomonas entomophila as the pathogen. We let the host populations either evolve against a nonevolving pathogen or coevolve with the same pathogen. We found that the coevolving hosts on average evolved higher survivorship against the coevolving pathogen and ancestral (nonevolving) pathogen relative to the hosts evolving against a nonevolving pathogen. The coevolving pathogens evolved greater ability to induce host mortality even in nonlocal (novel) hosts compared to infection by an ancestral (nonevolving) pathogen. Thus, our results clearly show that the evolved traits in the host and the pathogen under coevolution can be different from one‐sided adaptation. In addition, our results also show that the coevolving host–pathogen interactions can involve certain general mechanisms in the pathogen, leading to increased mortality induction in nonlocal or novel hosts.
Coevolution
Experimental Evolution
Melanogaster
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Enterococcus faecalis
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Background : The existence of microorganisms after root canal treatment can cause the failure of root canal treatment. Root canal treatment failure requiring retreatment, indicate the presence of facultative bacteria in infections, especially Enterococcus faecalis. The prevalence of infections due to Enterococcus faecalis ranged between 24% - 77%. The use of propolis in the field of dentistry was reported several years. has antibacterial, antiviral, antifungal, antiseptic, antibiotic, antioxidant and anti-inflammatory. Flavonoid found in significant amounts in propolis, even compared with most other bee products like honey, royal jelly, etc. Purpose : The aim of this study is to know the minimum inhibitoy concentration of propolis solution towards Enterococcus faecalis. Method : This research was laboratory experimental study. that used in this research is Melia Propolis with BPPOM RI POM. IT 054 616 861. This propolis solution was examined in Enterococcus faecalis ATCC 29212. Experimental method is serial dilution. Result : The result shown that propolis solution has ability to inhibit the growth of Enterococcus faecalis on concentration 6,25%. Conclusion : solution has antibacterial effect toward Enterococcus faecalis. Minimum inhibitory concentration (MIC) Enterococcus faecalis is 6,25%.
Enterococcus faecalis
Propolis
Antiseptic
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Enterococcus faecalis is responsible for most cases of endodontic treatment failure. Despite various conventional disinfection methods, root canals are not completely free of microorganisms. Photodynamic therapy (PDT) is a new antimicrobial strategy that involves the use of a non-toxic photosensitizer (PS) and a light source. The aim of this study was to evaluate the antimicrobial effect of PDT using diode laser and pyoktanin blue (PB) and confirm the nontoxicity of PB as a PS.Laser irradiation with an output power of 3 W was performed with PB as the PS to a bacterial solution containing E. faecalis. Then, the number of colony-forming units was counted. PB cytotoxicity was also assessed by the MTT assay.E. faecalis counts were reduced after laser irradiation, laser irradiation with PB, or the combination thereof compared to the control, non-irradiation or water. The 50% cytotoxic concentration value for adult human dermal fibroblasts incubated with PB for 1 min was 108 μg/ml.Diode laser irradiation in combination with PB as the PS is efficacious for the elimination of E. faecalis without toxic effects to human dermal fibroblasts. This strategy might be useful for root canal irrigants.
Enterococcus faecalis
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Enterococcus faecalis
Minimum bactericidal concentration
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