Colonization resistance

Vollaard, E. J.; Clasener, H. A. L.

doi:10.1128/aac.38.3.409

Cited by 475 publications

(313 citation statements)

References 60 publications

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“…The mammalian gut microbiota has been described as a virtual organ, playing a role not only in food digestion and the provision of nutrients, but also in host metabolism, neural development, and the development of a fully functional immune system. An intact, fully developed GI tract microbiota also protects the host against invasion by pathogenic microorganisms through a highly complex set of events known as "colonization resistance" (1). The consequences of disturbing the normally mutualistic association between the gut microbiota and the host can be extreme (2).…”

mentioning

confidence: 99%

Effect of broad- and narrow-spectrum antimicrobials on Clostridium difficile and microbial diversity in a model of the distal colon

Rea

Dobson

O'Sullivan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

330

263

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Vancomycin, metronidazole, and the bacteriocin lacticin 3147 are active against a wide range of bacterial species, including Clostridium difficile. We demonstrate that, in a human distal colon model, the addition of each of the three antimicrobials resulted in a significant decrease in numbers of C. difficile. However, their therapeutic use in the gastrointestinal tract may be compromised by their broad spectrum of activity, which would be expected to significantly impact on other members of the human gut microbiota. We used highthroughput pyrosequencing to compare the effect of each antimicrobial on the composition of the microbiota. All three treatments resulted in a decrease in the proportion of sequences assigned to the phyla Firmicutes and Bacteroidetes, with a corresponding increase in those assigned to members of the Proteobacteria. One possible means of avoiding such "collateral damage" would involve the application of a narrow-spectrum antimicrobial with specific anti-C. difficile activity. We tested this hypothesis using thuricin CD, a narrowspectrum bacteriocin produced by Bacillus thuringiensis, which is active against C. difficile. The results demonstrated that this bacteriocin was equally effective at killing C. difficile in the distal colon model but had no significant impact on the composition of the microbiota. This offers the possibility of developing a targeted approach to eliminating C. difficile in the colon, without collateral damage.gut microbiota | pyrosequencing | bacteriocin | antibiotic | thuricin

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mentioning

confidence: 99%

Effect of broad- and narrow-spectrum antimicrobials on Clostridium difficile and microbial diversity in a model of the distal colon

Rea

Dobson

O'Sullivan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

330

263

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“…Although residual drugs may be degraded by cooking procedures to some degree (XU et al, 1996;UNO et al, 2006) and inactivated to a variable extent in the intestines by decomposition of bacterial enzymes and by binding to bacteria and other faecal components, the possibility of inducing alteration of the intestinal flora and disruption of the colonization barrier is not unlikely ( VAN DER WAAIJ, 1982;EDLUND & NORD, 1993;VOLLARD & CLASENER, 1994;CERNIGLIA & KOTARSKI, 1999;EDLUND & NORD, 1999). Human intestinal microflora constitute a balanced and complex community inhabited by hundreds of bacterial species (CERNIGLIA & KOTARSKI, 1999) which are vital for the maintenance of a healthy human gastrointestinal tract since they inhibit colonization of pathogenic bacteria (VOLLARD & CLASENER, 1994) and intervene in the digestion and processing of various substances (CHADWICK et al, 1992). Although the side effects of drugs on human intestinal microflora can be more apparent during therapeutic applications where the tissue levels to be targeted are high, however, prolonged unwanted exposure to antibacterial residues may also disturb the equilibrium of the gut microflora by changing the population density and composition (antibacterials may reduce total numbers of some bacteria or selectively kill some vital species), by altering enzyme activity for the metabolism of endogenous and exogenous substances and by impairing colonization resistance (CERNIGLIA & KOTARSKI, 1999).…”

Section: Residual Antibacterials In Aquatic Farmed Items; Possible Efmentioning

confidence: 99%

Section: Residual Antibacterials In Aquatic Farmed Items; Possible Efmentioning

confidence: 99%

Antibacterial drugs in products originating from aquaculture: assessing the risks to public welfare

2010

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As aquaculture expands to meet human demand and compensate for pessimistic forecasts of fisheries catches, use of antibacterial agents to combat or forestall bacterial diseases is still a necessity, although effective vaccines and improved hygiene have aided drastically in this battle. The hazards for the consumer perspective arising from the imprudent use of such chemicals can be detrimental, especially if the residues persist above legal tolerance. These may include selection and dissemination of resistant bacteria, disruption of the colonization barrier in the human intestinal flora and allergic reactions. In cases that unlawful drugs reached the consumer via consumption of aquatic products, human health may be jeopardized even further. The present review article assesses these risks to human health.

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“…Although the majority of the gram-negative flora is comprised of antimicrobial-susceptible strains, subpopulations of resistant strains can exist through several mechanisms including spontaneous mutations, induction of resistance genes or exogenous acquisition of resistant strains [4,5,37]. The indirect effects of antimicrobial therapy targeting bacterial infections at other sites, can result in the overgrowth of these subpopulations of resistant strains with a concurrent decrease in bacterial concentrations of susceptible strains [25,26].…”

Section: Introductionmentioning

confidence: 99%

“…The human commensal flora provides the main ecological niche and reservoir for antimicrobialresistant gram-negative bacteria [37]. Although the majority of the gram-negative flora is comprised of antimicrobial-susceptible strains, subpopulations of resistant strains can exist through several mechanisms including spontaneous mutations, induction of resistance genes or exogenous acquisition of resistant strains [4,5,37].…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Impact of Bacterial Fitness and Repeated Antimicrobial Exposure on the Emergence of Multidrug-Resistant Gram-Negative Bacilli

D’Agata

Horn

Webb

2007

Math. Model. Nat. Phenom.

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Abstract. The emergence of multidrug resistance among gram-negative bacilli is complex. Numerous factors need to be considered, including the biological fitness cost of resistance, fitnesscompensatory mutations and frequency and type of antibiotic exposure. A mathematical model evaluating these complex relationships was developed in an individual colonized with strains of pan-susceptible, single-, two-and multidrug-resistant (MDR) gram-negative bacilli (GN). The effect of bacterial fitness, compensatory mutations and the frequency of three-antimicrobial regimen exposure to predominance of multidrug-resistant strains were quantified. The model predicts that initially, in the absence of antibiotic exposure, the biologically fitter pan-susceptible strain predominates over the resistant strains. Over time, the fitness of the MDR strains increases faster with repeated antimicrobial exposure, through compensatory-fitness mutations. Increasing the frequency of exposure to the three-antimicrobial regimen or, increasing the initial fitness of the resistant strains, substantially decreases the time to MDR-GN predominance. The model implies that when MDR-GN strains evolve into strains that are fitter than susceptible strains, a reduction in antimicrobial exposure may not result in a decrease of MDR-GN, since the absence of selective antimicrobial pressure would no longer favor susceptible strains. The model also implies that antimicrobial cycling may promote the emergence of MDR-GN.

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Colonization resistance

Cited by 475 publications

References 60 publications

Effect of broad- and narrow-spectrum antimicrobials on Clostridium difficile and microbial diversity in a model of the distal colon

Effect of broad- and narrow-spectrum antimicrobials on Clostridium difficile and microbial diversity in a model of the distal colon

Antibacterial drugs in products originating from aquaculture: assessing the risks to public welfare

Quantifying the Impact of Bacterial Fitness and Repeated Antimicrobial Exposure on the Emergence of Multidrug-Resistant Gram-Negative Bacilli

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