Epidemiology and outcome of Shigella, Salmonella and Campylobacter infections in travellers returning from the tropics with fever and diarrhoea.

Introduction: During a study on fever after a stay in the tropics, we aimed at investigating the epidemiology and outcome of invasive bacterial enteritis due to Shigella, Salmonella or Campylobacter spp. in patients diagnosed with febrile traveller's diarrhoea.

Methods: From April 2000 to September 2006, we evaluated prospectively 594 travellers presenting with fever and diarrhoea within a month after a stay in the tropics. Patients not found with a systemic infection were assumed to have febrile traveller's diarrhoea (TD). Invasive bacterial enteritis was confirmed by isolation of Shigella, Campylobacter or nontyphoidal Salmonella in stool cultures.

Results: Systemic infections (mainly malaria) were diagnosed in 259 (44%) evaluated travellers. Invasive bacterial enteritis, either alone or with another infection, was confirmed in 114 (34%) of the 335 remaining patients with febrile TD. Aetiologies were distributed between Campylobacter jejuni (47, 41%), Shigella spp. (43, 38%), Salmonella spp. (22, 19%) and mixed Campylobacter-Salmonella infection (2, 2%). Invasive bacterial enteritis accounted for about a third of febrile TD cases occurring after a stay in sub-Saharan Africa, North Africa/Middle East or Latin America, and for half of those occurring after a travel to southern Asia (including 33% only due to C. jejuni). Resistance to fluoroquinolones was exclusively observed in C. jejuni isolates, but at an overall rate of 53%. Clinical failure occurred in 33% of the patients with C. jejuni infection empirically treated with a fluoroquinolone.

Conclusion: Invasive bacterial enteritis was a frequent aetiology of febrile TD. C. jejuni was the leading pathogen after a travel to southern Asia, and was associated with high rate of resistance to fluoroquinolones and of clinical failure.