1. Co-infection with zoonotic Campylobacter and Salmonella Kim O. Gradel 1, Brian Kristensen 2, Tove Ejlertsen 1, Henrik C. Schønheyder 1, Henrik Nielsen 1 1 Aalborg Hospital, Aarhus University Hospital, Denmark 2 Aarhus University Hospital, Skejby, Aarhus, Denmark.

2. 2 Background I General interest of study group: acquisition of zoonotic infections, related to host characteristics such as age and comorbidity, which characterize frailty: little is known. Behavioural factors (e.g., food, travel, barbequing): much is known Literature: no published studies on Campylobacter/Salmonella co-infection (to our knowledge)

3. 3 Background II Bacteremia patients: Poly-microbial bacteremia patients are frailer than mono-infected Poly-microbial bacteremia is usually acquired nosocomially Zoonotic gastroenteritis is usually community-acquired: Co-infection in relation to host characteristics? Co-infection in relation to behavioural factors?

4. 4 Hypothesis Patients with zoonotic Salmonella and Campylobacter gastroenteritis co-infection are frailer than mono-infected Salmonella and Campylobacter gastroenteritis patients

5. 5 Setting Denmark North Jutland County Aarhus County All acutely ill patients admitted to the nearest hospital in their county Centralized clinical microbiology service in each county

6. 6 Study cohort All first-time Salmonella and Campylobacter in faecal specimens in the two Danish counties, 1991-2003. Co-infected: Patients with 0-7 days between isolation of Salmonella and Campylobacter Mono-infected: Salmonella patients Campylobacter patients

7. 7 Data linkage Study cohort Civil Registration System: - date of death Hospital Discharge Register: - comorbidity - hospitalization Unique personal identification number

8. 8 Results: n = 13,449: 0.85% (n =114) had co-infection 48.8% (n = 6,567) had Salmonella mono-infection 50.3% (n = 6,768) had Campylobacter mono-infection Days between Salmonella and Campylobacter specimens: 8 (7.0)‏2-7 7 (6.1)‏1 99 (86.8)‏0 Number (%)‏ Days

9. 9 Age distribution Median age: 26.2 years Median age: 35.2 years Median age: 26.8 years

10. 10 Comorbidity 0.7 (0.4-1.4)‏ 1.1 (0.6-2.0)‏ Odds ratio (95% CI)‏ 10.1% (n = 681)‏ 14.2 % (n = 930)‏ 13.2 % (n = 15) Comorbidity present Mono-infected Campylobacter (n = 6,768)‏ Mono-infected Salmonella (n = 6,567)‏ Co-infected (n = 114)‏

11. 11 Hospitalization 1.0 (0.6-1.5)‏ 0.7 (0.4-1.0)‏ Odds ratio (95% CI)‏ 24.7% (n = 1,673)‏ 33.2% (n = 2,182)‏ 24.6 % (n = 28)‏ Hospitalization Mono-infected Campylobacter (n = 6,768)‏ Mono-infected Salmonella (n = 6,567)‏ Co-infected (n = 114)‏

12. 12 Death within one year 0.8-1.3%2.2-2.9%0-3.2%95% CI 1.0% (n = 69)‏ 2.5% (n = 166)‏ 0% (n = 0)‏ Death Mono-infected Campylobacter (n = 6,768)‏ Mono-infected Salmonella (n = 6,567)‏ Co-infected (n = 114)‏

13. 13 Seasonal variation

14. 14 Salmonella serotype distribution 20.9%48.2%Other 0.8% 4.4%Unknown 26.2%14.9%S. Typhimurium 52.1%31.6%S. Enteritidis Mono-infected Salmonella (n = 6,567)‏ Co-infected (n = 114)‏ Serotype

15. 15 Danish Salmonella sources Danish Zoonosis Centre: Annual Report on Zoonoses in Denmark 2006 Travel (mean: 25%)‏

16. 16 Salmonella serotypes and foreign travel Unknown (%)‏ Travelling (%)‏ No travelling (%)‏ 3.318.179.2Other serotypes 23.6 6.771.2S. Typhimurium 39.814.951.3S. Enteritidis Serotype Hald T et al., Risk Analysis, 2004, 24, 255-269.

17. 17 Strengths and limitations Strengths: Population-based Data on comorbidity Data on hospitalization Data on long-term mortality Limitations: Low statistical precision Few data on antibiotic resistance No data on behavioural factors

18. 18 Conclusions Co-infected Salmonella/Campylobacter patients were not frailer than mono-infected patients. Co-infection apparently had no clinical implications. The higher proportion of exotic Salmonella serotypes amongst co- infected patients points to foreign travel.

19. 19 Thank you! Gràcies! Gracias! Tak!