Antimicrobial-drug Susceptibility of Human and Animal Salmonella Typhimurium, Minnesota, 1997–2003

摘要

We compared antimicrobial resistance phenotypesand pulsed-field gel electrophoresis (PFGE) subtypes of1,028 human and 716 animal Salmonella enterica serotypeTyphimurium isolates from Minnesota from 1997 to 2003.Overall, 29% of human isolates were multidrug resistant.Predominant phenotypes included resistance to ampicillin,chloramphenicol or kanamycin, streptomycin, sulfisoxa-zole, and tetracycline (ACSSuT or AKSSuT). Most humanmultidrug-resistant isolates belonged to PFGE clonal groupA, characterized by ACSSuT resistance (64%), or clonalgroup B, characterized by AKSSuT resistance (19%). Mostanimal isolates were from cattle (n = 358) or swine (n =251). Eighty-one percent were multidrug resistant; of these,54% were at least resistance phenotype ACSSuT, and 43%were at least AKSSuT. More than 80% of multidrug-resist-ant isolates had a clonal group A or B subtype. Resistanceto ceftriaxone and nalidixic acid increased, primarily amongclonal group A/ACSSuT isolates. Clonal group B/AKSSuTisolates decreased over time. These data support thehypothesis that food animals are the primary reservoir ofmultidrug-resistant S. Typhimurium