[Characterization of two typhoid fever outbreaks in Apartadó, Antioquia, 2005]. / Caracterización de dos brotes de fiebre tifoidea en Apartadó, Antioquia, 2005.

INTRODUCTION: The characterization of typhoid fever outbreaks is important because it is necessary to find the source of the infection and development control measures. OBJECTIVE: A typhoid fever outbreak is described from Apartadó and the Salmonella Typhi isolates characterized by phenotypic and genotypic methods. MATERIALS AND METHODS: From 44 patients, 15 blood cultures and 7 stools cultures were recovered. Phenotypic identification of isolates was done by biochemical and serological tests, and antibiotic susceptibility was tested. Genes hilA, invA and the IS200 marker were evaluated by polymerase chain reaction; pulsed field gel electrophoresis was used for the XbaI gene. Eight water samples were examined by polymerase chain reaction and culture methods in order to isolate Salmonella spp. RESULTS: Fifteen patients were confirmed for typhoid fever, 13 by blood cultures and two by stools cultures. All S. Typhi isolates were susceptible to the antimicrobials tested. The presence of hilA, invA and IS200 were confirmed by polymerase chain reaction in all isolates. The pulsed field gel electrophoresis method grouped 10 isolates in COINJPP.X01.0035 pattern, three in COINJPPX01.0002, one in COINJPP.X01.0012 and one in COINJPPX01.0037. Water isolates were negatives for Salmonella spp. CONCLUSIONS: Pulsed field gel electrophoresis discriminated the isolates in two outbreaks. Initially the cases were described as only one outbreak, by epidemiological criteria and phenotypic test. Additionally two isolates with different clonal origin were discriminated, indicating that they were unrelated to the other cases. It was not possible to confirm the infection source from water samples.