title: Influence of population density on antibiotic resistance.
abstract: Antibiotic consumption and population density as a measure of crowding in the community were related to the prevalence of antibiotic resistance of three cities in three different countries: St Johns in Newfoundland (Canada), Athens in Greece and Groningen in The Netherlands. Antibiotic consumption was expressed in DDD (defined daily dose), as DID (DDD/1000 inhabitants/day) and as DSD (DDD/km(2)). The prevalence of antibiotic-resistant Escherichia coli and enterococci was determined in faecal samples of healthy volunteers. In both Newfoundland (28 DID) and Greece (29 DID) the overall consumption of antibiotics was more than three times higher compared with that of The Netherlands (9 DID). The lowest prevalence of resistant E. coli against the majority of antibiotics tested was found for the samples from Newfoundland and was significant (P < 0.05) for cefazolin, oxytetracycline and trimethoprim. A poor correlation between the number of DID and the prevalence of resistance was observed [the Pearson correlation coefficient (Pcc) ranged between -0.93 and 0.87]. However, when population density was taken into consideration and antibiotic consumption was expressed in DSD, a strong correlation was observed (and Pcc ranged between 0.86 and 1.00). This study suggests that population density is an important factor in the development of antibiotic resistance and warrants special attention as a factor in resistance epidemiology.
authors.affiliation: Department of Medical Microbiology, University Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherland.
authors.forename: N
authors.initials: N
authors.lastname: Bruinsma
authors.forename: J M
authors.initials: JM
authors.lastname: Hutchinson
authors.forename: A E
authors.initials: AE
authors.lastname: van den Bogaard
authors.forename: H
authors.initials: H
authors.lastname: Giamarellou
authors.forename: J
authors.initials: J
authors.lastname: Degener
authors.forename: E E
authors.initials: EE
authors.lastname: Stobberingh
mesh_terms: D002170:Canada / Q000453:epidemiology; D004351:Drug Resistance; D004363:Drug Utilization; D016983:Enterococcus / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D005243:Feces / Q000382:microbiology; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009426:Netherlands / Q000453:epidemiology; D011156:Population Density