title: Prevalence and characterization of class 1 integrons in Escherichia coli of poultry and human origin.
abstract: A prospective study was conducted to determine the prevalence and the gene-cassette content of class 1 integrons in Escherichia coli of poultry and human origin. A total of 235 E. coli isolates were examined; 65 were derived from farm poultry, 80 from hospitalized, and 90 from nonhospitalized patients. Susceptibilities to a range of antimicrobial agents were determined by disk diffusion. Int1-specific polymerase chain reaction, conserved-segment polymerase chain reaction, and DNA sequencing were used to determine the presence, length, and content of integrons. The relatedness among the isolates was examined by pulsed-field gel electrophoresis of XbaI digests of genomic DNA. The integron carriage rate for poultry isolates was 49.2%, whereas the carriage rate for hospital isolates was 26.2% and for community 11.1%. Multidrug resistance (resistance to three or more classes of antibiotics) phenotypes were observed in 96.8% of the integron-positive isolates, whereas only 34.9% of nonintegron-carrying organisms were multidrug resistant (p < 0.001). Seven integron types ranging in size from 663 to 2674 bp were identified; six types were observed in poultry isolates, five in hospital, and three in community isolates. Each integron type carried a distinct gene-cassette combination. The most prevalent gene cassettes belonged to the aad and dfr families. Identical integrons were detected in E. coli of human and poultry origin. A large reservoir of integrons exists in E. coli of poultry origin. The horizontal transfer of class 1 integrons among bacteria of poultry and human origins may contribute in the dissemination of antimicrobial resistance.
authors.affiliation: First Department of Propaedeutic Medicine, Laiko General Hospital, Athens, Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Vasilakopoulou
authors.forename: Mina
authors.initials: M
authors.lastname: Psichogiou
authors.forename: Leonidas
authors.initials: L
authors.lastname: Tzouvelekis
authors.forename: Panayiotis T
authors.initials: PT
authors.lastname: Tassios
authors.forename: Chris
authors.initials: C
authors.lastname: Kosmidis
authors.forename: George
authors.initials: G
authors.lastname: Petrikkos
authors.forename: Eleftheria S
authors.initials: ES
authors.lastname: Roma
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Charvalos
authors.forename: Maria
authors.initials: M
authors.lastname: Passiotou
authors.forename: Athina
authors.initials: A
authors.lastname: Avlami
authors.forename: George L
authors.initials: GL
authors.lastname: Daikos
mesh_terms: D000818:Animals; D001769:Blood / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry; D052978:Disk Diffusion Antimicrobial Tests; D004352:Drug Resistance, Microbial / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D005517:Foodborne Diseases / Q000517:prevention & control; D041981:Gastrointestinal Tract / Q000382:microbiology; D006115:Greece; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data; D032023:Integrons / Q000235:genetics*; D010045:Outpatients / Q000706:statistics & numerical data; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011200:Poultry / Q000382:microbiology*; D013183:Sputum / Q000382:microbiology; D013492:Suppuration / Q000382:microbiology; D014556:Urine / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial