title: Antimicrobial resistance in Shiga toxin-producing Escherichia coli O157 and O26 isolates from beef cattle.
abstract: This study was conducted to determine the prevalence of antimicrobial resistance in  Shiga toxin-producing Escherichia coli (STEC) O157 (n = 241) and O26 (n = 11) isolated from beef  cattle and to characterize their antimicrobial resistance profiles. Resistance to  dihydrostreptomycin was detected most frequently (STEC O157, 9.5%; STEC O26, 54.5%), followed by  resistance to oxytetracycline (7.9%; 45.5%) and ampicillin (5.4%; 36.4%). Resistance to one or  more antimicrobial agents was detected in 13.3% (32/241) of the STEC O157 isolates and 54.5% (6/11)  of the STEC O26 isolates. The antimicrobial resistance rate in the STEC O26 isolates was  significantly higher than that in the STEC O157 isolates (P = 0.002, Fisher's exact test). The  antimicrobial resistance rate in the STEC O157 isolates possessing both stx(1) and stx(2) genes  was 26.3% (15/57), while that in the isolates possessing stx(2c) gene alone was 3.9%  (3/77). These findings suggest that the antimicrobial resistance in STEC O157 is associated with  serogroups and the Shiga toxin genotype.
authors.affiliation: Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry, and Fisheries, Tokyo 100-8950, Japan. yoshimasa_sasaki＠nm.maff.go.jp
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Masaru
authors.initials: M
authors.lastname: Usui
authors.forename: Mariko
authors.initials: M
authors.lastname: Murakami
authors.forename: Mika
authors.initials: M
authors.lastname: Haruna
authors.forename: Akemi
authors.initials: A
authors.lastname: Kojima
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Asai
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D008826:Microbial Sensitivity Tests; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents