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 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 SCREENING PHYTOCHEMICAL AND ANTI-METHICILLIN RESISTANT (MRSA) ACTIVITY OF 70 % ETHANOLIC EXTRACT FROM THE STEM BARK OF ALBIZIA LEBBECK(L.) BENTH.(FABACEAE)

2018 ◽  
Vol 6 (6) ◽  
pp. 1-6
Author(s):  
Yao KANGA ◽  
CAMARA Djeneb ◽  
KOUASSI Kouadio Aubin ◽  
ZIRIHI Guédé Noël
Keyword(s):  
Antibacterial Activity ◽  
Reference Strain ◽  
Ethanolic Extract ◽  
Stem Bark ◽  
Drug Resistant ◽  
Albizia Lebbeck ◽  
Antimicrobial Drugs ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

The emergence of multi-drug resistant strains and limitations of present antimicrobial drugs have led to continuous search for natural products as curative agents for Anti-methicillin resistantinfections. The aim of this study was to evaluate antibacterial activity of an ethanolic extract from Albizia lebbeckstem bark against Anti-methicillin resistant. Methods and Results : The methods of dissemination swab on muller-hinton agar and double dilution were used to evaluate the antibacterial activity of 70 % ethanolic extract of stem bark of Albizia lebbeck.All multi-resistant strains of Staphylococcus aureus and the reference strain (ATCC 25923) were sensitive to 70 % ethanolic extract of the stem bark of Albizia lebbeck. The MBCvary from 0,49 mg/mL to 2mg/mL. Also, the phytochemical screening of this extract revealed the presence of  Polyphenols, Gallic tannins, Catechin tanninsand Flavonoids. These findings confirm that an 70 % ethanolic extract from Albizia lebbeck stem bark inhibited growth of Anti-methicillin resistant at low concentration and could be utilised as an alternative Anti-methicillin resistantagent.

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 Chlamydophila psittaci in homing and feral pigeons and zoonotic transmission

2010 ◽  
Vol 59 (11) ◽  
pp. 1348-1353 ◽  
Author(s):  
V. Dickx ◽  
D. S. A. Beeckman ◽  
L. Dossche ◽  
P. Tavernier ◽  
D. Vanrompay
Keyword(s):  
Protein A ◽  
Homing Pigeon ◽  
Zoonotic Transmission ◽  
Antimicrobial Drugs ◽  
Homing Pigeons ◽  
Feral Pigeons ◽  
Chlamydophila Psittaci ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
The City

Chlamydiosis is a zoonotic disease in birds caused by Chlamydophila psittaci, an obligate intracellular bacterium. There are seven known avian outer-membrane protein A genotypes, A–F and E/B. The importance of genotyping lies in the fact that certain genotypes tend to be associated with certain hosts and a difference in virulence. Genotype B is the most prevalent in pigeons, but the more virulent genotypes A and D have also been discovered. The current study assessed the prevalence of C. psittaci in 32 Belgian homing-pigeon facilities and in 61 feral pigeons captured in the city of Ghent, Belgium. Additionally, zoonotic transmission of C. psittaci was investigated in the homing-pigeon facilities. Homing pigeons were often infected, as at least one of the lofts was positive in 13 of the 32 (40.6 %) pigeon breeding facilities. Genotypes B, C and D were detected. Zoonotic transmission was discovered in 4 of the 32 (12.5 %) pigeon fanciers, revealing genotype D in two of them, whilst genotyping was unsuccessful for the other two human pharyngeal swabs. This study clearly demonstrates the possible risk of C. psittaci zoonotic transmission from homing pigeons. Pigeon fanciers often (37.5 %) used antibiotics for prevention of respiratory disease. Because of the risk of developing drug-resistant strains, regular use of antimicrobial drugs must be avoided. This study is believed to be the first to detect C. psittaci in Belgian feral pigeons. The prevalence rate in the city of Ghent was extremely low, which is beneficial for public health.

scholarly journals Antimicrobial Susceptibility Profiles and Resistance Genes in Genus Aeromonas spp. Isolated from the Environment and Rainbow Trout of Two Fish Farms in France

2021 ◽  
Vol 9 (6) ◽  
pp. 1201
Author(s):  
Niki Hayatgheib ◽  
Ségolène Calvez ◽  
Catherine Fournel ◽  
Lionel Pineau ◽  
Hervé Pouliquen ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Antibiotic Use ◽  
Resistant Bacteria ◽  
Aquatic Environments ◽  
Fish Farms ◽  
Antibiotic Resistant ◽  
Resistant Strains ◽  
Trout Farms ◽  
Susceptibility Profiles ◽  
The Impact

This study presents the occurrence and abundance of Aeromonas antibiotic-resistant bacteria (ARB) and genes (ARGs) isolated from water, biofilm and fish in two commercial trout farms before and one week after flumequine treatment. Wild (WT) and non-wild (NWT) strains were determined for quinolones (flumequine, oxolinic acid and enrofloxacin), oxytetracycline (OXY), florfenicol (FFN), trimethoprim-sulfamethoxazole (TMP) and colistin (COL), and pMAR (presumptive multi-resistant) strains were classified. Forty-four ARGs for the mentioned antibiotics, β-lactams and multi-resistance were quantified for 211 isolates. BlaSHV-01, mexF and tetE were the dominant ARGs. A greater occurrence and abundance of tetA2, sul3, floR1, blaSHV-01 and mexF were observed for NWT compared to WT. The occurrence of pMAR and NWT Aeromonas for quinolones, OXY, FFN, TMP, COL and ARGs depended on the Aeromonas origin, antibiotic use and the presence of upstream activities. Our results revealed the impact of a flumequine treatment on Aeromonas present on a fish farm through an increase in NWT and pMAR strains. The link between fish and their environment was shown by the detection of identical ARB and ARGs in the two types of samples. There appears to be a high risk of resistance genes developing and spreading in aquatic environments.

scholarly journals Pulmonary exacerbation due to colistin-resistant Stenotrophomonas maltophilia in a Bulgarian cystic fibrosis patient

Folia Medica ◽  
2016 ◽  
Vol 58 (2) ◽  
pp. 136-140 ◽  
Author(s):  
Gergana P. Stoyanova ◽  
Tanya V. Strateva ◽  
Svetlana T. Atanasova ◽  
Dimitrinka S. Miteva ◽  
Vera E. Papochieva ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Stenotrophomonas Maltophilia ◽  
Treatment Options ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Lung Damage ◽  
Pulmonary Exacerbation ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
The Impact

Abstract In patients with cystic fibrosis (CF) lung damage secondary to chronic infection is the main cause of death. Treatment of lung disease to reduce the impact of infection, inflammation and subsequent lung injury is therefore of major importance. As Pseudomonas aeruginosa is the dominant pathogen in CF patients it has been the major target of all treatment strategies, possible antibiotic regimens and recommendations for years. More sophisticated antibiotic therapies introduced over the last decades have helped to improve the prognosis in cystic fibrosis, but then new multidrug-resistant pathogens emerged. We present a case of cystic fibrosis in a 16-year-old boy with pulmonary exacerbation due to colistin-resistant Stenotrophomonas maltophilia. This case raises some interesting questions regarding the antibiotic policy and treatment options in our country for patients with CF and multidrug-resistant strains. Colistin is used at present in Bulgaria as a strategic last option for the CF patients but with the advent of new more drug-resistant strains therapeutic approach should change - for instance, there should be restrictions imposed on the use of levofloxacin and trimethoprim/sulfamethoxazole which are regarded as “cheap and not so potent” antibiotics suitable for any infection and use them only in strict dependence on the respective culture results.

Antibiotic Resistance: A Global, Interdisciplinary Concern

2011 ◽  
Vol 73 (6) ◽  
pp. 314-321 ◽  
Author(s):  
Richard A. Stein
Keyword(s):  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Environmental Science ◽  
Clinical Medicine ◽  
Antibiotic Use ◽  
Global Perspective ◽  
Interdisciplinary Framework ◽  
Resistant Strains ◽  
Effective Use ◽  
The Impact

This article presents a brief overview of the impact that antibiotic use in clinical medicine and in other settings, such as agriculture and animal farming, exerts on antimicrobial resistance. Resistance has been described to all antibiotics that are currently in use, and resistant strains were sometimes reported as soon as months after specific antibiotics became commercially available. There are many examples in which the increasing prevalence of resistant microbial strains jeopardized the continuing effective use of the respective antibiotics in clinical medicine. In addition to resistant infections that occur in health-care establishments, one of the recent challenges is the emergence of pathogens, such as MRSA, in the community, among individuals without any apparent risk factors for the infection. The transmission of resistant pathogens and antimicrobial resistance determinants across different components of the ecosystem transforms antibiotic resistance into a topic that extends beyond the scope of clinical medicine and needs to be visualized through an integrated global perspective that should incorporate a broad range of disciplines, including molecular genetics, microbiology, food science, ecology, agriculture, and environmental science. Understanding this complex multi- and interdisciplinary framework will enable the implementation of the most appropriate interventions toward determining the dynamics of antimicrobial resistance, limiting the emergence and spread of resistant strains, and ensuring the ongoing effective and safe use of antibiotics.

An integrated molecular dynamics, principal component analysis and residue interaction network approach reveals the impact of M184V mutation on HIV reverse transcriptase resistance to lamivudine

2014 ◽  
Vol 10 (8) ◽  
pp. 2215-2228 ◽  
Author(s):  
Soumendranath Bhakat ◽  
Alberto J. M. Martin ◽  
Mahmoud E. S. Soliman
Keyword(s):  
Reverse Transcriptase ◽  
Interaction Network ◽  
Principal Component ◽  
Hiv Reverse Transcriptase ◽  
Residue Interaction ◽  
Resistant Strains ◽  
Hiv Rt ◽  
Drug Resistant Strains ◽  
The Impact ◽  
M184v Mutation

The emergence of different drug resistant strains of HIV-1 reverse transcriptase (HIV RT) remains of prime interest in relation to viral pathogenesis as well as drug development.

scholarly journals Drug Resistance and Population Structure of Mycobacterium tuberculosis Beijing Strains Isolated in Poland

2015 ◽  
Vol 64 (4) ◽  
pp. 399-401 ◽  
Author(s):  
Monika Kozińska ◽  
Ewa Augustynowicz-Kopeć
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Population Structure ◽  
Relative Risk ◽  
Beijing Genotype ◽  
Drug Resistant ◽  
Foreign Born ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Genotype Infection

In total, 1095 Mycobacterium tuberculosis clinical isolates from 282 patients with drug-resistant and 813 with drug-sensitive tuberculosis (TB) in Poland during 2007–2011 were analysed. Seventy-one (6.5%) patients were found to have strains of Beijing genotype as defined by spoligotyping. The majority of patients were Polish–born; among foreign-born a large proportion came from Chechnya and Vietnam. Analysis showed strong associations between Beijing genotype infection and MDR, pre-XDR and XDR resistance, with a considerable relative risk among new patients, suggesting that this is due to increased spread of drug-resistant strains rather than acquisition of resistance during treatment.

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