title: Epidemiology of Campylobacter jejuni infections in Sweden, November 2011-October 2012: is the severity of infection associated with C. jejuni sequence type?
abstract: BACKGROUND
  Campylobacter jejuni is among the most frequent causes of bacterial gastroenteritis in Europe. Over 8,000 C. jejuni multilocus sequence typing sequence types (STs) have been described; ST-21 and ST-45 have been identified as the most frequent types in all human studies so far. In contrast to other STs, ST-22 has been associated with the Guillain-Barré syndrome and ST-677 was recently linked to severe systemic infections in Finland. We investigated risk factors associated with hospitalisation in individuals with C. jejuni infections acquired in Sweden.
  
  
  METHODS
  A total of 1,075 individuals with domestically acquired C. jejuni infection diagnosed between November 2011 and October 2012 in Sweden were included in this retrospective cohort study. Typing data for the isolates as well as clinical data including hospitalisation dates and diagnosis codes for individuals with C. jejuni infection were obtained. Factors associated with hospitalisation and length of hospitalisation were investigated by multivariable analysis.
  
  
  RESULTS
  A total of 289 individuals were hospitalised due to C. jejuni infection (26.8%); those with co-morbidities were over 14 times more likely to become hospitalised than those without (odds ratio [OR]: 14.39, 95% confidence interval [CI]: 6.84-30.26). Those with underlying co-morbidities were also hospitalised longer than those without (4.22 days vs. 2.86 days), although this was not statistically significant. C. jejuni ST-257 (OR: 2.38; CI: 1.08-5.23), but not ST-22 or ST-677, was significantly associated with hospitalisation.
  
  
  CONCLUSIONS
  ST-677 was not associated with increased hospitalisation or a longer hospital stay in our study whilst ST-257 was. However, individuals with C. jejuni infections were generally more frequently hospitalised than previously demonstrated; this requires further consideration including possible targeted interventions.
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.|European Programme for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden; heli.simmonds@folkhalsomyndigheten.se; heli.simmonds@hotmail.com.
authors.forename: Heli
authors.initials: H
authors.lastname: Harvala
authors.affiliation: National Veterinary Institute of Sweden, Uppsala, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosendal
authors.affiliation: National Veterinary Institute of Sweden, Uppsala, Sweden.
authors.forename: Elina
authors.initials: E
authors.lastname: Lahti
authors.affiliation: National Veterinary Institute of Sweden, Uppsala, Sweden.
authors.forename: Eva O
authors.initials: EO
authors.lastname: Engvall
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Brytting
authors.affiliation: Public Health Agency of Sweden, Solna, Sweden.|Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Wallensten
authors.affiliation: National Veterinary Institute of Sweden, Uppsala, Sweden.
authors.forename: Ann
authors.initials: A
authors.lastname: Lindberg
keywords: Campylobacter; epidemiology; gastrointestinal pathogens; sequence type