Antimicrobial-resistant nontyphoidal Salmonella is associated with excess bloodstream infections and hospitalizations.
BACKGROUND
Nontyphoidal Salmonella is a leading cause of foodborne illness. Few studies have explored the health consequences of antimicrobial-resistant Salmonella.


METHODS
The National Antimicrobial Resistance Monitoring System (NARMS) performs susceptibility testing on nontyphoidal Salmonella isolates. The Foodborne Diseases Active Surveillance Network (FoodNet) ascertains outcomes for patients with culture-confirmed Salmonella infection, in 9 states, each of which participates in NARMS. We analyzed the frequency of bloodstream infection and hospitalization among patients with resistant infections. Isolates defined as resistant to a clinically important agent were resistant to 1 or more of the following agents: ampicillin, ceftriaxone, ciprofloxacin, gentamicin, and/or trimethoprim-sulfamethoxazole.


RESULTS
During 1996-2001, NARMS received 7370 serotyped, nontyphoidal Salmonella isolates from blood or stool. Bloodstream infection occurred more frequently among patients infected with an isolate resistant to > or =1 clinically important agent (adjusted odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2-2.1), compared with patients with pansusceptible infection. During 1996-2001, FoodNet staff ascertained outcomes for 1415 patients who had isolates tested in NARMS. Hospitalization with bloodstream infection occurred more frequently among patients infected with an isolate resistant to > or =1 clinically important agent (adjusted OR, 3.1; 95% CI, 1.4-6.6), compared with patients with pansusceptible infection.


CONCLUSIONS
Patients with antimicrobial-resistant nontyphoidal Salmonella infection were more likely to have bloodstream infection and to be hospitalized than were patients with pansusceptible infection. Mitigation of antimicrobial resistance in Salmonella will likely benefit human health.
Varma
Jay K
JK
Epidemic Intelligence Service, Epidemiology Program Office, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. jvarma@cdc.gov
Molbak
Kåre
K
Barrett
Timothy J
TJ
Beebe
James L
JL
Jones
Timothy F
TF
Rabatsky-Ehr
Therese
T
Smith
Kirk E
KE
Vugia
Duc J
DJ
Chang
Hwa-Gan H
HG
Angulo
Frederick J
FJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D001769:Blood / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D005243:Feces / Q000382:microbiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012475:Salmonella / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D014774:Virulence
D000900:Anti-Bacterial Agents