title: Disinfectant and antibiotic susceptibility profiles of Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States.
abstract: The disinfectant and antibiotic susceptibility profiles of 344 Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States were determined. A low prevalence of antibiotic resistance was observed (14%). The highest prevalences  of resistance were to sulfisoxazole (10.5%), tetracycline (9.9%), streptomycin (7%), and chloramphenicol (4.9%). Four strains were resistant to eight antibiotics (two strains from ground beef and one strain each from hide and preevisceration carcass swabs of cull cattle at harvest). Pulsed-field  gel electrophoresis analysis of the E. coli O157:H7 strains revealed two major groups (designated 1 and 2) composed of 17 and 20 clusters, respectively. Clusters 1A, 1B, 1C, and 1G.1 were associated with multidrug-resistant strains. There was no observed correlation between disinfectant  resistance and antibiotic resistance. Sixty-nine (20%) of the 344 strains were resistant to chlorhexidine or benzalkonium chloride or the MICs of benzyldimethyldodecylammonium chloride were elevated. Inducible resistance was observed at elevated concentrations of antibiotics (1.4%) and disinfectants  (6.1%). The highest rate of disinfectant inducible resistance was to OdoBan, quaternary ammonium chlorides, and the surface disinfectants F25, FS512, and MG, which are used in dairies, restaurants, and food processing plants. High MICs (1,024 to 4,096 m g/ml) of acetic, lactic, and citric  acids were found. The decreasing order of acid potency based on molar MICs (MICs(molar)) was acetic, citric, and lactic acid. The correlation of the concentration of dissociated organic acids and MICs(molar) strongly suggests that the observed inhibition of E. coli  O157:H7 was primarily due to dissociated forms of the acids.
authors: U.S. Department of Agriculture, Agricultural Research Service, Southern Plains Agricultural Research Center, College Station, Texas 77845, USA. ross.beier@yahoo.com
authors: Ross C
authors: RC
authors: Beier
authors: Toni L
authors: TL
authors: Poole
authors: Dayna M
authors: DM
authors: Brichta-Harhay
authors: Robin C
authors: RC
authors: Anderson
authors: Kenneth M
authors: KM
authors: Bischoff
authors: Charles A
authors: CA
authors: Hernandez
authors: James L
authors: JL
authors: Bono
authors: Terrance M
authors: TM
authors: Arthur
authors: T G
authors: TG
authors: Nagaraja
authors: Tawni L
authors: TL
authors: Crippen
authors: Cynthia L
authors: CL
authors: Sheffield
authors: David J
authors: DJ
authors: Nisbet
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle / Q000382:microbiology*; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D019453:Escherichia coli O157 / Q000187:drug effects*; D005243:Feces / Q000382:microbiology; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D006197:Hair / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D008461:Meat Products / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D012867:Skin / Q000382:microbiology; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D004202:Disinfectants