title: Antimicrobial-resistant Salmonella spp isolated from healthy broiler chickens after slaughter.
abstract: Of 105 Salmonella organisms of any serotype selected from a sample of 1,824 serotyped salmonellae isolated during a nationwide bacteriologic survey of healthy broiler chickens after slaughter, 60 (57%) were resistant to 1 or more antimicrobial agents and 47 (45%) were resistant to 2 or more agents. Highest resistance was to tetracycline (45%), streptomycin (41%), sulfisoxazole (19%), gentamicin (10%), and trimethoprim/sulfamethoxazole (8%). Additional isolates of S typhimurium, heidelberg, agona, and enteritidis were selected from the sample of 1,824 isolates for testing because of the high frequency with which these 4 serotypes are isolated from human patients. The highest frequency of resistance among 104 isolates of S heidelberg, 92 isolates of S typhimurium, and 30 isolates of S agona was to streptomycin (33 to 57%), sulfisoxazole (33 to 50%), tetracycline (26 to 50%), and gentamicin (13 to 40%); 51 to 63% of these isolates were resistant to 1 or more agents and 37 to 59% were resistant to 2 or more agents. Resistance to ampicillin among these 3 serotypes was uncommon (0 to 4%). In contrast, 15 of 19 tested isolates (79%) of S enteritidis were resistant to ampicillin and 13 of the 19 isolates (68%) were resistant only to ampicillin. This pattern of resistance was associated with a specific bacteriophage type and indicated the potential role of bacterial clones in determining the frequency and patterns of antimicrobial resistance in populations of broiler chickens. Resistance to gentamicin and trimethoprim/sulfamethoxazole was higher than that previously reported and is of public health concern because of the frequency with which these drugs are used to treat bacterial infections in human patients.
authors.affiliation: Enteric Diseases Branch, Centers for Disease Control, Atlanta, GA 30333.
authors.forename: L A
authors.initials: LA
authors.lastname: Lee
authors.forename: V L
authors.initials: VL
authors.lastname: Threatt
authors.forename: N D
authors.initials: ND
authors.lastname: Puhr
authors.forename: P
authors.initials: P
authors.lastname: Levine
authors.forename: K
authors.initials: K
authors.lastname: Ferris
authors.forename: R V
authors.initials: RV
authors.lastname: Tauxe
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens / Q000382:microbiology*; D004352:Drug Resistance, Microbial; D008460:Meat / Q000382:microbiology; D011201:Poultry Diseases / Q000382:microbiology*; D012475:Salmonella / Q000187:drug effects* / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents