title: Characterization of class 1 integrons-mediated antibiotic resistance among calf pathogenic Escherichia coli.
abstract: Escherichia coli isolates from calf diarrhea cases (n=22) in the Beijing surrounding region in China were characterized for disease serotype, virulence factors, antimicrobial susceptibility pattern and class 1 integrons. 59% (n=13) of the isolates were positive for the int I1 gene. The presence and genetic content of class 1 integrons in 13 E. coli isolates were examined by PCR and sequencing. Sequencing analysis revealed six gene cassettes, which encoded resistance to trimethoprim (dfrA1, dfrA17), aminoglycosides (aadB, aadA1 and aadA5) and chloramphenicol (cmlA). The gene cassette arrays dfrA1-orf (45%) and aadB-orf-cmlA (32%) were most prevalent among these isolates. These data revealed the high prevalence of class 1 integrons among calf pathogenic E. coli isolates in the Beijing surrounding region in China, which may provide important and useful surveillance information reflecting specific antibiotic selective pressure.
authors.affiliation: Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing 100094, PR China.
authors.forename: Xiangdang
authors.initials: X
authors.lastname: Du
authors.forename: Zhangqi
authors.initials: Z
authors.lastname: Shen
authors.forename: Beibei
authors.initials: B
authors.lastname: Wu
authors.forename: Shengchao
authors.initials: S
authors.lastname: Xia
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Shen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D002681:China; D002702:Chloramphenicol Resistance / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D032023:Integrons; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012703:Serotyping; D014296:Trimethoprim Resistance / Q000235:genetics; D037521:Virulence Factors / Q000032:analysis
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D037521:Virulence Factors