Samuel Coenen

Prof. Samuel Coenen

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Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 May 2012 in Gut
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Journal Article
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FMFrancis Mégraud
Francis Mégraud
Samuel CoenenSamuel Coenen
Samuel Coenen
AVAnn Versporten
Ann Versporten
MKManfred Kist
Manfred Kist
MLManuel Lopez-Brea
Manuel Lopez-Brea
SPStudy Group participants
Study Group participants
Objective: Resistance to antibiotics is the major cause of treatment failure of Helicobacter pylori infection. A study was conducted to assess prospectively the antibacterial resistance rates of H pylori in Europe and to study the link between outpatient antibiotic use and resistance levels in different countries. Design: Primary antibiotic resistance rates of H pylori were determined from April 2008 to June 2009 in 18 European countries. Data on yearly and cumulative use over several years of systemic antibacterial agents in ambulatory care for the period 2001–8 were expressed in Defined Daily Doses (DDD) per 1000 inhabitants per day. The fit of models and the degree of ecological association between antibiotic use and resistance data were assessed using generalised linear mixed models. Results: Of 2204 patients included, H pylori resistance rates for adults were 17.5% for clarithromycin, 14.1% for levofloxacin and 34.9% for metronidazole, and were significantly higher for clarithromycin and levofloxacin in Western/Central and Southern Europe (>20%) than in Northern European countries (<10%). Model fit improved for each additional year of antibiotic use accumulated, but the best fit was obtained for 2005. A significant association was found between outpatient quinolone use and the proportion of levofloxacin resistance (p=0.0013) and between the use of long-acting macrolides only and clarithromycin resistance (p=0.036). Conclusion: In many countries the high rate of clarithromycin resistance no longer allows its empirical use in standard anti- H pylori regimens. The knowledge of outpatient antibiotic consumption may provide a simple tool to predict the susceptibility of H pylori to quinolones and to macrolides and to adapt the treatment strategies.

1 February 2007 in The Lancet
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Journal Article
Closed access
SMSurbhi Malhotra-Kumar
Surbhi Malhotra-Kumar
CLChristine Lammens
Christine Lammens
Samuel CoenenSamuel Coenen
Samuel Coenen
KHKoen Van Herck
Koen Van Herck
HGHerman Goossens
Herman Goossens

1 October 2013 in The Lancet
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Journal Article
Open access
Paul LittlePaul Little
Paul Little
BSBeth Stuart
Beth Stuart
NFNick Francis
Nick Francis
EDElaine Douglas
Elaine Douglas
STSarah Tonkin-Crine
Sarah Tonkin-Crine
LYLucy Yardley
Lucy Yardley
High-volume prescribing of antibiotics in primary care is a major driver of antibiotic resistance. Education of physicians and patients can lower prescribing levels, but it frequently relies on highly trained staff. We assessed whether internet-based training methods could alter prescribing practices in multiple health-care systems. After a baseline audit in October to December, 2010, primary-care practices in six European countries were cluster randomised to usual care, training in the use of a C-reactive protein (CRP) test at point of care, in enhanced communication skills, or in both CRP and enhanced communication. Patients were recruited from February to May, 2011. This trial is registered, number ISRCTN99871214. The baseline audit, done in 259 practices, provided data for 6771 patients with lower-respiratory-tract infections (3742 [55·3%]) and upper-respiratory-tract infections (1416 [20·9%]), of whom 5355 (79·1%) were prescribed antibiotics. After randomisation, 246 practices were included and 4264 patients were recruited. The antibiotic prescribing rate was lower with CRP training than without (33% vs 48%, adjusted risk ratio 0·54, 95% CI 0·42-0·69) and with enhanced-communication training than without (36% vs 45%, 0·69, 0·54-0·87). The combined intervention was associated with the greatest reduction in prescribing rate (CRP risk ratio 0·53, 95% CI 0·36-0·74, p<0·0001; enhanced communication 0·68, 0·50-0·89, p=0·003; combined 0·38, 0·25-0·55, p<0·0001). Internet training achieved important reductions in antibiotic prescribing for respiratory-tract infections across language and cultural boundaries. European Commission Framework Programme 6, National Institute for Health Research, Research Foundation Flanders.

23 June 2009 in BMJ
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Journal Article
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CChris Butler
Chris Butler
KHK Hood
K Hood
TVT Verheij
T Verheij
Paul LittlePaul Little
Paul Little
HMHasse Melbye
Hasse Melbye
HGH Goossens
H Goossens
Objective To describe variation in antibiotic prescribing for acute cough in contrasting European settings and the impact on recovery. Design Cross sectional observational study with clinicians from 14 primary care research networks in 13 European countries who recorded symptoms on presentation and management. Patients followed up for 28 days with patient diaries. Setting Primary care. Participants Adults with a new or worsening cough or clinical presentation suggestive of lower respiratory tract infection. Main outcome measures Prescribing of antibiotics by clinicians and total symptom severity scores over time. Results 3402 patients were recruited (clinicians completed a case report form for 99% (3368) of participants and 80% (2714) returned a symptom diary). Mean symptom severity scores at presentation ranged from 19 (scale range 0 to 100) in networks based in Spain and Italy to 38 in the network based in Sweden. Antibiotic prescribing by networks ranged from 20% to nearly 90% (53% overall), with wide variation in classes of antibiotics prescribed. Amoxicillin was overall the most common antibiotic prescribed, but this ranged from 3% of antibiotics prescribed in the Norwegian network to 83% in the English network. While fluoroquinolones were not prescribed at all in three networks, they were prescribed for 18% in the Milan network. After adjustment for clinical presentation and demographics, considerable differences remained in antibiotic prescribing, ranging from Norway (odds ratio 0.18, 95% confidence interval 0.11 to 0.30) to Slovakia (11.2, 6.20 to 20.27) compared with the overall mean (proportion prescribed: 0.53). The rate of recovery was similar for patients who were and were not prescribed antibiotics (coefficient −0.01, P<0.01) once clinical presentation was taken into account. Conclusions Variation in clinical presentation does not explain the considerable variation in antibiotic prescribing for acute cough in Europe. Variation in antibiotic prescribing is not associated with clinically important differences in recovery. Trial registration Clinicaltrials.gov NCT00353951.

30 May 2006 in Journal of Antimicrobial Chemotherapy
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Journal Article
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MFMatus Ferech
Matus Ferech
Samuel CoenenSamuel Coenen
Samuel Coenen
SMSurbhi Malhotra-Kumar
Surbhi Malhotra-Kumar
KDKaterina Dvorakova
Katerina Dvorakova
EHErik Hendrickx
Erik Hendrickx
EGESAC Project Group
ESAC Project Group
Background: The ESAC project, granted by DG SANCO of the European Commission, is an international network of surveillance systems, aiming to collect comparable and reliable data on antibiotic use in Europe. Data on outpatient antibiotic use were collected from 34 countries using the ATC/DDD methodology. Methods: For the period 1997–2003, data on outpatient use of systemic antibiotics aggregated at the level of the active substance were collected and expressed in DDD (WHO, version 2004) per 1000 inhabitants per day (DID). Outpatient antibiotic (ATC J01) use in 25 European countries, able to deliver valid data, was analysed. Results: Total outpatient antibiotic use in 2003 varied by a factor of 3 between the country with the highest (31.4 DID in Greece) and the country with the lowest (9.8 DID in the Netherlands) use. General use patterns in individual countries as well as trends during the period 1997–2003 are described in this paper, while major antibiotic classes (penicillins, cephalosporins, macrolides/lincosamides/streptogramins and quinolones) will be analysed in detail in separate papers. Conclusion: The ESAC project established for the first time a credible alternative to industry sources for the collection of internationally comparable data on antibiotic use in Europe, based on cooperation between regulatory authorities, scientific societies, health insurers and professional organizations. These data provide a tool for assessing public health strategies aiming to optimize antibiotic prescribing.

1 December 2011 in Journal of Antimicrobial Chemotherapy
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OGon behalf of the ESAC Project Group
on behalf of the ESAC Project Group
NANiels Adriaenssens
Niels Adriaenssens
Samuel CoenenSamuel Coenen
Samuel Coenen
AVAnn Versporten
Ann Versporten
AMArno Muller
Arno Muller
HGHerman Goossens
Herman Goossens
To describe total outpatient systemic antibiotic use in Europe from 1997 to 2009 and to analyse statistically trends of total use and composition of use over time. For the period 1997–2009, data on outpatient use of systemic antibiotics aggregated at the level of the active substance were collected and expressed in defined daily doses (WHO, version 2011) and packages per 1000 inhabitants per day (DID and PID, respectively). Outpatient antibiotic (ATC J01) use in DID in the 33 European countries able to deliver valid data was analysed using longitudinal and compositional data analyses. Total outpatient antibiotic use in 2009 varied by a factor of 3.8 between the countries with the highest (38.6 DID in Greece) and lowest (10.2 DID in Romania) use. For Europe, a significant increase was found in total outpatient antibiotic use, as well as a significant seasonal variation, which decreased over time from 1997 to 2009. Relative use of penicillins and quinolones significantly increased over time with respect to sulphonamides and trimethoprim, and relative use of quinolones increased with respect to macrolide/lincosamide/streptogramin as well. More detailed analyses of these major antibiotic subgroups will be described in separate papers. Outpatient antibiotic use in Europe measured as DID has increased since 1997, whereas seasonal variation has decreased over time. European Surveillance of Antimicrobial Consumption (ESAC) data on outpatient antibiotic use in Europe enable countries to audit their antibiotic use. Complemented by longitudinal and compositional data analyses, these data provide a tool for assessing public health strategies aimed at reducing antibiotic resistance and optimizing antibiotic prescribing.