title: Antibiotic resistance patterns in Escherichia coli from gulls in nine European countries.
abstract: BACKGROUND
  The prevalence of antibiotic resistant faecal indicator bacteria from humans and food production animals has increased over the last decades. In Europe, resistance levels in Escherichia coli from these sources show a south-to-north gradient, with more widespread resistance in the Mediterranean region compared to northern Europe. Recent studies show that resistance levels can be high also in wildlife, but it is unknown to what extent resistance levels in nature conform to the patterns observed in human-associated bacteria.
  
  
  METHODS
  To test this, we collected 3,158 faecal samples from breeding gulls (Larus sp.) from nine European countries and tested 2,210 randomly isolated E. coli for resistance against 10 antibiotics commonly used in human and veterinary medicine.
  
  
  RESULTS
  Overall, 31.5% of the gull E. coli isolates were resistant to ≥1 antibiotic, but with considerable variation between countries: highest levels of isolates resistant to ≥1 antibiotic were observed in Spain (61.2%) and lowest levels in Denmark (8.3%). For each tested antibiotic, the Iberian countries were either the countries with the highest levels or in the upper range in between-country comparisons, while northern countries generally had a lower proportion of resistant E. coli isolates, thereby resembling the gradient of resistance seen in human and food animal sources.
  
  
  CONCLUSIONS
  We propose that gulls may serve as a sentinel of environmental levels of antibiotic resistant E. coli to complement studies of human-associated microbiota.
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Stedt
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden ; Department of Infectious Diseases, Kalmar County Hospital, Kalmar, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Bonnedahl
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
authors.forename: Jorge
authors.initials: J
authors.lastname: Hernandez
authors.affiliation: Section of Clinical Microbiology and Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: McMahon
authors.affiliation: UCD School of Agriculture & Food Science, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Badrul
authors.initials: B
authors.lastname: Hasan
authors.affiliation: UCD School of Agriculture & Food Science, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Björn
authors.initials: B
authors.lastname: Olsen
authors.affiliation: UCD School of Agriculture & Food Science, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Mirva
authors.initials: M
authors.lastname: Drobni
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Waldenström
keywords: Antibiotic resistance; Escherichia Coli; antibiotics; birds; gulls; wildlife