Antimicrobial Drug
Resistance of
Salmonella Isolates
from Meat and
Humans, Denmark
Marianne N. Skov,* Jens Strodl Andersen,†
Søren Aabo,† Steen Ethelberg,‡
Frank M. Aarestrup,† Anders Hay Sørensen,†
Gitte Sørensen,† Karl Pedersen,†
Steen Nordentoft,† Katharina E.P. Olsen,‡
Peter Gerner-Smidt,‡ and Dorte L. Baggesen†
We compared 8,144 Salmonella
isolates collected
from meat imported to or produced in Denmark, as well as
from Danish patients. Isolates from imported meat showed
a higher rate of antimicrobial drug resistance, including
multidrug resistance, than did isolates from domestic meat.
Isolates from humans showed resistance rates lower than
those found in imported meat but higher than in domestic
meat. These findings indicate that programs for controlling
resistant Salmonella spp. are a global issue.
Salmonella spp. are among the most common causes of
human bacterial gastroenteritis worldwide, and food
animals are important reservoirs of the bacteria (1). In
recent years, an increase in the occurrence of antimicrobial
drug–resistant Salmonella spp. has been observed in sever-
al countries (2–5). Fatality rates are higher for patients
with infections caused by drug-resistant Salmonella spp.,
and these patients are more likely to require hospitalization
and to be hospitalized for longer periods than are patients
with infections caused by antimicrobial drug–susceptible
Salmonella spp. (6,7).
Antimicrobial drug resistance of Salmonella spp. iso-
lated from food animals in Denmark has so far been rela-
tively low (8). However, an estimated 30% of all poultry,
10% of all pork, and 50% of all beef sold in Denmark is
imported (9). Imported meat is therefore an important
potential source of human infection with drug-resistant
Salmonella spp. We compared antimicrobial drug resist-
ance of Salmonella isolates from both imported meat and
meat produced within Denmark (domestic meat), as well
as from outpatients with diarrhea.
Salmonella isolates from humans and meat were
obtained from July 1998 through June 2002. Isol