1. Institut de Veille Sanitaire (National Institute of Public Health, InVS), Saint-Maurice, France
2. Centre National de Reference des Vibrions et du Choléra, Institut Pasteur (National reference centre on vibrios and cholera, Pasteur Institute), Paris, France.
Two returning French travellers were hospitalised in late March 2007 for cholera caused by Vibrio cholerae
serogroup O1 serotype Ogawa. In a separate event, a third case was hospitalised in early April 2007. All three travellers had returned from a trip to India (Rajasthan). They all required urgent specialised care in an intensive care unit and were treated by intravenous rehydration therapy and antibiotics. The V. cholerae
O1 strains isolated during the first cluster of two cases and the third unrelated case were tested for antibiotic susceptibility. These tests showed resistance to nalidixic acid with decreased susceptibility to ofloxacine and ciprofloxacin. The three isolates were sensitive to tetracycline and doxycycline, and one of them was sensitive to trimethoprim-sulfamethoxazole.
The vast majority of cholera cases worldwide are treated by oral rehydration therapy (ORT) which, when administered in a timely and sufficient manner, has transformed the prognosis of cholera since the early 1960s and remains the mainstay of cholera treatment . A total of 129 imported cases of confirmed cholera were diagnosed in France between 1973 and 2005, with a median of three diagnosed cases per year . An additional two cases were diagnosed in 2006. Although many may go undetected, the number of diagnosed cases is on the decrease. Imported cholera cases, however, are diagnosed increasingly in infants or elderly persons who may not well tolerate massive fluids loss [2,3]. Antibiotics may be a useful adjunct  as they have been shown to reduce the duration of diarrhoea [1,4-8], the volume of diarrhoea [5,6,8], the volume of fluids required for rehydration [9,10], the duration of hospital stay  and the duration of excretion of V. cholerae [4-8]. Although emergence of multiple antibiotic resistance during cholera epidemic outbreaks has been documented over the past 30 years [11,12], there is little data on the prognosis of cholera in patients infected with resistant strains. Available data points to longer-lasting and more severe cholera in patients treated with inappropriate antibiotics . In industrialised countries, treating with inappropriate antibiotics may be associated with increased morbidity in patients and higher costs to the community .
In a 2004 publication , the World Health Organization (WHO) examined the possible antibiotic regimen indicated when needed in outbreak or highly endemic situations. The WHO recommends single-dose doxycycline or tetracycline qid per three days or erythromycin in young children qid per four days. Although fluoroquinolones are not recommended by the WHO for treating suspected cholera, they are widely used in the first-line treatment of diarrhoea caused by infections acquired in developing countries. V. cholerae O1 strains resistant to fluoroquinolones have emerged in India  and Bangladesh [15,16] over the past years for a number of reasons. Quite logically, it was only a matter of time before resistant strains were imported to Europe.
The impact of emerging antibioresistant cholera strains is greatest on patients in endemic countries but also affects imported cases. Community- or hospital-based clinicians considering antibiotic therapy for cholera in returning travellers before susceptibility testing should bear in mind that at least three cases imported to France from Rajasthan in 2007 showed decreased susceptibility to fluoroquinolones.
*The laboratory investigation group included: Hélène Jean-Pierre, Montpellier University Hospital; Valérie Lalande, Saint-Antoine University Hospital; Patrice Lemaître, Creil Hospital; Christophe Paquet, Institut de Veille Sanitaire; Estelle Ronco, Garches Hospital; Jacques Tankovic, Saint-Antoine University Hospital.