title: Typhoid fever in the United States, 1999-2006.
abstract: BACKGROUND
  Typhoid fever in the United States has increasingly been due to infection with antimicrobial-resistant Salmonella ser Typhi. National surveillance for typhoid fever can inform prevention and treatment recommendations.
  
  
  OBJECTIVE
  To assess trends in infections with antimicrobial-resistant S. Typhi.
  
  
  METHODS
  Cross-sectional, laboratory-based surveillance study.
  
  
  METHODS
  We reviewed data from 1999-2006 for 1902 persons with typhoid fever who had epidemiologic information submitted to the Centers for Disease Control and Prevention (CDC) and 2016 S. Typhi isolates sent by participating public health laboratories to the National Antimicrobial Resistance Monitoring System Laboratory at the CDC for antimicrobial susceptibility testing.
  
  
  METHODS
  Proportion of S. Typhi isolates demonstrating resistance to 14 antimicrobial agents and patient risk factors for antimicrobial-resistant infections.
  
  
  RESULTS
  Patient median age was 22 years (range, <1-90 years); 1295 (73%) were hospitalized and 3 (0.2%) died. Foreign travel within 30 days of illness was reported by 1439 (79%). Only 58 travelers (5%) had received typhoid vaccine. Two hundred seventy-two (13%) of 2016 isolates tested were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole (multidrug-resistant S. Typhi [MDRST]); 758 (38%) were resistant to nalidixic acid (nalidixic acid-resistant S. Typhi [NARST]) and 734 NARST isolates (97%) had decreased susceptibility to ciprofloxacin. The proportion of NARST increased from 19% in 1999 to 54% in 2006. Five ciprofloxacin-resistant isolates were identified. Patients with resistant infections were more likely to report travel to the Indian subcontinent: 85% of patients infected with MDRST and 94% with NARST traveled to the Indian subcontinent, while 44% of those with susceptible infections did (MDRST odds ratio, 7.5; 95% confidence interval, 4.1-13.8; NARST odds ratio, 20.4; 95% confidence interval, 12.4-33.9).
  
  
  CONCLUSIONS
  Infection with antimicrobial-resistant S. Typhi strains among US patients with typhoid fever is associated with travel to the Indian subcontinent, and an increasing proportion of these infections are due to S. Typhi strains with decreased susceptibility to fluoroquinolones.
authors.affiliation: Enteric Diseases Epidemiology Branch, Centers for Disease Control and Prevention, 4770 Buford Hwy, MS F-22, Atlanta, GA 30341, USA. mlynch1@cdc.gov
authors.forename: Michael F
authors.initials: MF
authors.lastname: Lynch
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Blanton
authors.forename: Sandra
authors.initials: S
authors.lastname: Bulens
authors.forename: Christina
authors.initials: C
authors.lastname: Polyak
authors.forename: Jazmin
authors.initials: J
authors.lastname: Vojdani
authors.forename: Jennifer
authors.initials: J
authors.lastname: Stevenson
authors.forename: Felicia
authors.initials: F
authors.lastname: Medalla
authors.forename: Ezra
authors.initials: E
authors.lastname: Barzilay
authors.forename: Kevin
authors.initials: K
authors.lastname: Joyce
authors.forename: Timothy
authors.initials: T
authors.lastname: Barrett
authors.forename: Eric Daniel
authors.initials: ED
authors.lastname: Mintz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D006801:Humans; D007223:Infant; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012307:Risk Factors; D012485:Salmonella typhi / Q000187:drug effects*; D014195:Travel; D014435:Typhoid Fever / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology; D055815:Young Adult