title: Emergence of multidrug-resistant Salmonella enterica serotype Newport infections resistant to expanded-spectrum cephalosporins in the United States.
abstract: We describe a field investigation in New England that identified the emergence and epidemiology of new strains of multidrug-resistant Salmonella, Newport-MDRAmpC, and summarize the Center for Disease Control and Prevention's surveillance data for these infections. In Massachusetts, the prevalence of Newport-MDRAmpC among Salmonella serotype Newport isolates obtained from humans increased from 0% (0/14) in 1998 to 53% (32/60) in 2001 (P<.001). In a retrospective case-control study, infection with Newport-MDRAmpC was domestically acquired and was associated with exposure to a dairy farm. Isolates from both humans and cattle had indistinguishable or closely related antibiograms and pulsed-field gel electrophoresis patterns. Nationally, the prevalence of ceftriaxone-resistant Salmonella increased from 0.5% in 1998 to 2.4% in 2001; 85% of the isolates in 2001 were Newport-MDRAmpC, and at least 27 states have isolated these strains from humans, cattle, or ground beef. These data document the widespread emergence of Newport-MDRAmpC strains in the United States and show that the 5-fold increase in the prevalence of Salmonella resistant to expanded-spectrum cephalosporins, between 1998 and 2001, is primarily due to the emergence of Newport-MDRAmpC strains.
authors.affiliation: Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office, Centers for Disease Control and Prevention, National Center for Infectious Diseases, Atlanta, Georgia, USA. agupta25@jhmi.edu.
authors.forename: Amita
authors.initials: A
authors.lastname: Gupta
authors.forename: John
authors.initials: J
authors.lastname: Fontana
authors.forename: Colleen
authors.initials: C
authors.lastname: Crowe
authors.forename: Barbara
authors.initials: B
authors.lastname: Bolstorff
authors.forename: Alison
authors.initials: A
authors.lastname: Stout
authors.forename: Susan
authors.initials: S
authors.lastname: Van Duyne
authors.forename: Mike P
authors.initials: MP
authors.lastname: Hoekstra
authors.forename: Jean M
authors.initials: JM
authors.lastname: Whichard
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Barrett
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Angulo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001426:Bacterial Proteins; D016022:Case-Control Studies; D002417:Cattle; D018550:Cephalosporin Resistance; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005516:Food Microbiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012480:Salmonella Infections / Q000209:etiology; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics; D012703:Serotyping; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases