A nalidixic acid-resistant Salmonella enteritidis outbreak in Popayán, Cauca, 2011]

Introduction. Salmonella Enteritidis is recognized worldwide as one of the main agents of human gastrointestinal infection. Several reports indicate the presence of isolates with decreased sensitivity to ciprofloxacin that can lead to a delayed response or the development of resistance during treatment. Objective. To describe and characterize isolates of Salmonella Enteritidis associated to an outbreak of food-borne diseases in Popayan, Cauca. Materials and methods. Ten Salmonella Enteritidis isolates from nine patients and one food sample (chicken sandwich) were analyzed by biochemical tests, serotyping and antimicrobial sensitivity. The minimum inhibitory concentration to ciprofloxacin was determined by E-test and the genetic profile of the isolates was tested by pulsed field gel electrophoresis (PFGE) with XbaI and Blnl enzymes. Results. Salmonella Enteritidis was identified in all isolates. They were resistant to nalidixic acid and had a decreased sensitivity to ciprofloxaxin between 0.25 and 0.5 mu g/ml; all isolates were sensitive to all the other antimicrobials we tested. Ten isolates were grouped by PFGE with the XbaI enzyme in the COIN11. JEG.X01.0038 pattern, and seven isolates were confirmed with the BlnI enzyme using the COIN11. JEG. A26.0009 pattern. Conclusion. We report for the first time an outbreak of nalidixic acid-resistant Salmonella Enteritidis in Colombia and confirmed by phenotypic and genotypic analysis the association between the isolates from patients and the chicken sandwich as the source of infection.