scholarly journals Population structure across scales facilitates coexistence and spatial heterogeneity of antibiotic-resistant infections

2018 ◽  
Author(s):  
Madison S. Krieger ◽  
Carson E. Denison ◽  
Thayer L. Anderson ◽  
Martin A. Nowak ◽  
Alison L. Hill
Keyword(s):  
Population Structure ◽  
Evolutionary Dynamics ◽  
Resistance Management ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
Host Population ◽  
Antibiotic Resistant ◽  
Resistance Risk ◽  
Geographical Regions ◽  
Wide Range

ABSTRACTAntibiotic-resistant infections are a growing threat to human health, but basic features of the eco-evolutionary dynamics remain unexplained. Most prominently, there is no clear mechanism for the long-term coexistence of both drug-sensitive and resistant strains at intermediate levels, a ubiquitous pattern seen in surveillance data. Here we show that accounting for structured or spatially-heterogeneous host populations and variability in antibiotic consumption can lead to persistent coexistence over a wide range of treatment coverages, drug efficacies, costs of resistance, and mixing patterns. Moreover, this mechanism can explain other puzzling spatiotemporal features of drug-resistance epidemiology that have received less attention, such as large differences in the prevalence of resistance between geographical regions with similar antibiotic consumption or that neighbor one another. We find that the same amount of antibiotic use can lead to very different levels of resistance depending on how treatment is distributed in a transmission network. We also identify parameter regimes in which population structure alone cannot support coexistence, suggesting the need for other mechanisms to explain the epidemiology of antibiotic resistance. Our analysis identifies key features of host population structure that can be used to assess resistance risk and highlights the need to include spatial or demographic heterogeneity in models to guide resistance management.

scholarly journals Host population structure and treatment frequency maintain balancing selection on drug resistance

2017 ◽  
Author(s):  
Sarah Cobey ◽  
Edward B. Baskerville ◽  
Caroline Colijn ◽  
William Hanage ◽  
Christophe Fraser ◽  
...  
Keyword(s):  
Population Structure ◽  
Balancing Selection ◽  
Antibiotic Use ◽  
Host Population ◽  
Antimicrobial Drugs ◽  
Treatment Frequency ◽  
Specific Variation ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
The Impact

AbstractIt is a truism that antimicrobial drugs select for resistance, but explaining pathogen- and population-specific variation in patterns of resistance remains an open problem. Like other common commensals, Streptococcus pneumoniae has demonstrated persistent coexistence of drug-sensitive and drug-resistant strains. Theoretically, this outcome is unlikely. We modeled the dynamics of competing strains of S. pneumoniae to investigate the impact of transmission dynamics and treatment-induced selective pressures on the probability of stable coexistence. We find that the outcome of competition is extremely sensitive to structure in the host population, although coexistence can arise from age-assortative transmission models with age-varying rates of antibiotic use. Moreover, we find that the selective pressure from antibiotics arises not so much from the rate of antibiotic use per se but from the frequency of treatment: frequent antibiotic therapy disproportionately impacts the fitness of sensitive strains. This same phenomenon explains why serotypes with longer durations of carriage tend to be more resistant. These dynamics may apply to other potentially pathogenic, microbial commensals and highlight how population structure, which is often omitted from models, can have a large impact.

scholarly journals 1232. Phylogenomics of Enterococcus faecium From South America: Revisiting Worldwide VRE Population Structure

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S374-S374
Author(s):  
Rafael Rios ◽  
Jinnethe Reyes ◽  
Lina P Carvajal ◽  
Sergios-Orestis Kolokotronis ◽  
Paul Planet ◽  
...  
Keyword(s):  
Population Structure ◽  
South America ◽  
Latin American ◽  
Phylogenetic Analyses ◽  
Animal Origin ◽  
Research Support ◽  
Worldwide Population ◽  
Clade B ◽  
Geographical Regions ◽  
Wide Range

Abstract Background Previous studies have suggested that the population structure of E. faecium is composed of two main clades; a commensal clade (designated clade B) and a hospital-associated clade (Clade A) that encompass most of the clinical and animal isolates. The phylogenetic analyses leading to these results have been accomplished with the notable absence of isolates from diverse geographical regions (including South America). We aimed to refine the worldwide population structure of E. faecium by including 55 representative genomes from isolates obtained from five Latin American countries recovered between 1998 and 2014. Methods We sequenced our 55 representative isolates and selected other 285 genomes, from public databases, obtained across different regions (36 countries), different sources (animal, commensal, and clinical strains) and a wide range of dates of isolation (1946–2017). We characterized the genomes by presence/absence of resistance, virulence and mobile elements, and of CRISPR-cas systems. We analyzed the phylogeny of the entire population, selected the genomes belonging to clade A to examine recombination patterns and performed Bayesian molecular clock analysis excluding recombinant regions. Results Two major clades were identified, as previously reported. However, a higher degree of variation in clade A was found. Indeed, we identified a subclade (subclade I) that diverged ~894 years ago, and clearly distinguished clinical isolates from those of animal origin (distributed among a number of smaller early-branching subclades). A further split within the clinical subclade (subclade II) that diverged around ~371 years ago was also evident. Latin American isolates were distributed within subclades I (48%) and II (42%). Isolates in “animal” branches exhibited an average recombination of 34 Kbp, where it was 5 Kbp and 21 Kbp for subclades I and II, respectively. More resistance determinants were found in subclade II (62%), followed by I (54%) and absence of cas was the norm in the clinical subclades. Conclusion Inclusion of E. faecium isolates from diverse geographical region supports a continuous evolution of these organisms causing human infections. Important evolutionary events seem to favor emergence of novel subclades capable to cause important morbidity and mortality. Disclosures J. Munita, Pfizer: Grant Investigator, Research grant. C. Arias, Merck & Co., Inc.: Grant Investigator, Research support. MeMed: Grant Investigator, Research support. Allergan: Grant Investigator, Research support.

Change in Antibiotic Use in Secondary and Tertiary Hospitals Nationwide After a National Antimicrobial Stewardship Campaign Was Launched in China, 2011–2016: An Observational Study

2020 ◽  
Vol 221 (Supplement_2) ◽  
pp. S148-S155 ◽  
Author(s):  
Yonghong Xiao ◽  
Ping Shen ◽  
Beiwen Zheng ◽  
Kai Zhou ◽  
Qixia Luo ◽  
...  
Keyword(s):  
Observational Study ◽  
Antimicrobial Stewardship ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
Resistant Bacteria ◽  
Total Drug ◽  
Antibiotic Resistant ◽  
Drug Procurement ◽  
Carbapenem Resistant ◽  
Tertiary Hospitals

Abstract Background An antimicrobial stewardship campaign was launched in 2011 by the Ministry of Health. This study aimed to assess the achievements and trends in the clinical use of antibiotics in secondary and tertiary hospitals following this campaign in China. Methods This observational study analyzed nationwide hospital antibiotic procurement and consumption data and antibiotic-resistance surveillance data based on claims filed in 2010–2016. Results After a 6-year national campaign, the proportion of outpatients and surgical patients who received antibiotic treatment decreased from 19.5% to 8.5% and from 97.9% to 38.3%, respectively. The intensity of antibiotic use among inpatients decreased from 85.3±29.8 defined daily dosage (DDD) per 100 patient days to 48.5±8.0 DDD per 100 patient days. Moreover, the antibiotic procurement expenditure among hospitals declined from 22.3% of total drug procurement costs in 2010 to 12.1% in 2016, although total drug procurement costs doubled during that time. The incidence of methicillin-resistant Staphylococcus aureus isolates also dropped (from 54.4% in 2010 to 34.4% in 2016), as did the proportion of carbapenem-resistant Pseudomonas aeruginosa isolates (from 30.8% to 22.3%). Conclusions The 6-year campaign successfully reduced antibiotic consumption and irrational drug use in Chinese hospitals which was associated with declines in the prevalence of common antibiotic-resistant bacteria.

scholarly journals Outpatient consumption of antibiotics is linked to antibiotic resistance in Europe: results from the European Surveillance of Antimicrobial Consumption

2005 ◽  
Vol 10 (8) ◽  
Author(s):  
A Johnson
Keyword(s):  
European Union ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Selective Pressure ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
European Countries ◽  
Antimicrobial Consumption ◽  
Antibiotic Resistant ◽  
Resistant Strains

There is increasing recognition that antibiotic consumption provides a major selective pressure for the emergence and persistence of antibiotic-resistant strains of bacteria. In 2001, a European Union Council Recommendation stated that data should be gathered on antibiotic use and antimicrobial resistance in European countries

scholarly journals Awareness of Appropriate Antibiotic Use in Primary Care for Influenza-Like Illness: Evidence of Improvement from UK Population-Based Surveys

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 690
Author(s):  
Koen B. Pouwels ◽  
Laurence S. J. Roope ◽  
James Buchanan ◽  
Liz Morrell ◽  
Sarah Tonkin-Crine ◽  
...  
Keyword(s):  
United Kingdom ◽  
Online Survey ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
Population Based ◽  
White People ◽  
The United Kingdom ◽  
Wide Range ◽  
Minority Ethnic ◽  
Representative Samples

Influenza-like illnesses (ILI) account for a significant portion of inappropriate antibiotic use. Patient expectations for antibiotics for ILI are likely to play a substantial role in ‘unnecessary’ antibiotic consumption. This study aimed to investigate trends in awareness of appropriate antibiotic use and antimicrobial resistance (AMR). Three sequential online surveys of independent representative samples of adults in the United Kingdom investigated expectations for, and consumption of, antibiotics for ILI (May/June 2015 (n = 2064); Oct/Nov 2016 (n = 4000); Mar 2017 (n = 4000)). Respondents were asked whether they thought antibiotics were effective for ILI and about their antibiotic use. Proportions and 95% confidence intervals (CI) were calculated for each question and interactions with respondent characteristics were tested using logistic regression. Over the three surveys, the proportion of respondents who believed antibiotics would “definitely/probably” help an ILI fell from 37% (95% CI 35–39%) to 28% (95% CI 26–29%). Those who would “definitely/probably” visit a doctor in this situation fell from 48% (95% CI 46–50%) to 36% (95% CI 34–37%), while those who would request antibiotics during a consultation fell from 39% (95% CI 37–41%) to 30% (95% CI 29–32%). The percentage of respondents who found the information we provided about AMR “new/surprising” fell from 34% (95% CI 32–36%) to 28% (95% CI 26–31%). Awareness improved more among black, Asian and minority ethnic (BAME) than white people, with little other evidence of differences in improvements between subgroups. Whilst a degree of selection bias is unavoidable in online survey samples, the results suggest that awareness of AMR and appropriate antibiotic use has recently significantly improved in the United Kingdom, according to a wide range of indicators.

scholarly journals Antibiotic Reduction Campaigns Do Not Necessarily Decrease Bacterial Resistance: the Example of Methicillin-Resistant Staphylococcus aureus

2013 ◽  
Vol 57 (9) ◽  
pp. 4410-4416 ◽  
Author(s):  
Lidia Kardaś-Słoma ◽  
Pierre-Yves Boëlle ◽  
Lulla Opatowski ◽  
Didier Guillemot ◽  
Laura Temime
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Resistance ◽  
Antibiotic Prescription ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Content Type ◽  
The Impact ◽  
Prescription Changes

ABSTRACTInterventions designed to reduce antibiotic consumption are under way worldwide. While overall reductions are often achieved, their impact on the selection of antibiotic-resistant selection cannot be assessed accurately from currently available data. We developed a mathematical model of methicillin-sensitive and methicillin-resistantStaphylococcus aureus(MSSA and MRSA) transmission inside and outside the hospital. A systematic simulation study was then conducted with two objectives: to assess the impact of antibiotic class-specific changes during an antibiotic reduction period and to investigate the interactions between antibiotic prescription changes in the hospital and the community. The model reproduced the overall reduction in MRSA frequency in French intensive-care units (ICUs) with antibiotic consumption in France from 2002 to 2003 as an input. However, the change in MRSA frequency depended on which antibiotic classes changed the most, with the same overall 10% reduction in antibiotic use over 1 year leading to anywhere between a 69% decrease and a 52% increase in MRSA frequency in ICUs and anywhere between a 37% decrease and a 46% increase in the community. Furthermore, some combinations of antibiotic prescription changes in the hospital and the community could act in a synergistic or antagonistic way with regard to overall MRSA selection. This study shows that class-specific changes in antibiotic use, rather than overall reductions, need to be considered in order to properly anticipate the impact of an antibiotic reduction campaign. It also highlights the fact that optimal gains will be obtained by coordinating interventions in hospitals and in the community, since the effect of an intervention in a given setting may be strongly affected by exogenous factors.

scholarly journals Host population structure and treatment frequency maintain balancing selection on drug resistance

2017 ◽  
Vol 14 (133) ◽  
pp. 20170295 ◽  
Author(s):  
Sarah Cobey ◽  
Edward B. Baskerville ◽  
Caroline Colijn ◽  
William Hanage ◽  
Christophe Fraser ◽  
...  
Keyword(s):  
Population Structure ◽  
Balancing Selection ◽  
Antibiotic Use ◽  
Host Population ◽  
Antimicrobial Drugs ◽  
Treatment Frequency ◽  
Specific Variation ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
The Impact

It is a truism that antimicrobial drugs select for resistance, but explaining pathogen- and population-specific variation in patterns of resistance remains an open problem. Like other common commensals, Streptococcus pneumoniae has demonstrated persistent coexistence of drug-sensitive and drug-resistant strains. Theoretically, this outcome is unlikely. We modelled the dynamics of competing strains of S. pneumoniae to investigate the impact of transmission dynamics and treatment-induced selective pressures on the probability of stable coexistence. We find that the outcome of competition is extremely sensitive to structure in the host population, although coexistence can arise from age-assortative transmission models with age-varying rates of antibiotic use. Moreover, we find that the selective pressure from antibiotics arises not so much from the rate of antibiotic use per se but from the frequency of treatment: frequent antibiotic therapy disproportionately impacts the fitness of sensitive strains. This same phenomenon explains why serotypes with longer durations of carriage tend to be more resistant. These dynamics may apply to other potentially pathogenic, microbial commensals and highlight how population structure, which is often omitted from models, can have a large impact.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

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