title: Antimicrobial drug resistance in Escherichia coli from humans and food animals, United States, 1950-2002.
abstract: We conducted a retrospective study of Escherichia coli isolates recovered from human and food animal samples during 1950-2002 to assess historical changes in antimicrobial drug resistance. A total of 1,729 E. coli isolates (983 from humans, 323 from cattle, 138 from chickens, and 285 from pigs) were tested for susceptibility to 15 antimicrobial drugs. A significant upward trend in resistance was observed for ampicillin (p<0.001), sulfonamide (p<0.001), and tetracycline (p<0.001). Animal strains showed increased resistance to 11/15 antimicrobial agents, including ampicillin (p<0.001), sulfonamide (p<0.01), and gentamicin (p<0.001). Multidrug resistance (≥3 antimicrobial drug classes) in E. coli increased from 7.2% during the 1950s to 63.6% during the 2000s. The most frequent co-resistant phenotype observed was to tetracycline and streptomycin (29.7%), followed by tetracycline and sulfonamide (29.0%). These data describe the evolution of resistance after introduction of new antimicrobial agents into clinical medicine and help explain the range of resistance in modern E. coli isolates.
authors.affiliation: Food and Drug Administration, Laurel, Maryland 20708, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Tadesse
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zhao
authors.forename: Emily
authors.initials: E
authors.lastname: Tong
authors.forename: Sherry
authors.initials: S
authors.lastname: Ayers
authors.forename: Aparna
authors.initials: A
authors.lastname: Singh
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Bartholomew
authors.forename: Patrick F
authors.initials: PF
authors.lastname: McDermott
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D002645:Chickens; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D006801:Humans; D008826:Microbial Sensitivity Tests; D011201:Poultry Diseases / Q000382:microbiology; D012189:Retrospective Studies; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents