Antimicrobial-drug susceptibility of human and animal Salmonella typhimurium, Minnesota, 1997-2003.
We compared antimicrobial resistance phenotypes and pulsed-field gel electrophoresis (PFGE) subtypes of 1,028 human and 716 animal Salmonella enterica serotype Typhimurium 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, sulfisoxazole, and tetracycline (ACSSuT or AKSSuT). Most human multidrug-resistant isolates belonged to PFGE clonal group A, characterized by ACSSuT resistance (64%), or clonal group B, characterized by AKSSuT resistance (19%). Most animal 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-resistant isolates had a clonal group A or B subtype. Resistance to ceftriaxone and nalidixic acid increased, primarily among clonal group A/ACSSuT isolates. Clonal group B/AKSSuT isolates decreased over time. These data support the hypothesis that food animals are the primary reservoir of multidrug-resistant S. Typhimurium.
Acute Disease Investigation and Control Section, Minnesota Department of Health, Minneapolis, Minnesota 55164-0975, USA. stephanie.wedel@health.state.mn.us
Stephanie D
SD
Wedel
Jeffrey B
JB
Bender
Fe T
FT
Leano
David J
DJ
Boxrud
Craig
C
Hedberg
Kirk E
KE
Smith
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D008910:Minnesota / Q000453:epidemiology; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics; D013997:Time Factors
D000900:Anti-Bacterial Agents