Molecular epidemiology of multiply antibiotic-resistant Shigella flexneri in Fortaleza, Brazil.

In northeastern Brazil, strains of Shigella flexneri resistant to multiple antibiotics are often found in patients in both urban areas and community hospitals. This study used pulsed-field gel electrophoresis (PFGE) and plasmid analysis to further analyze the molecular epidemiology of Shigella flexneri strains isolated from hospitals and an urban community in Fortaleza, Brazil. Twenty-six strains of S. flexneri from three distinct areas in the city of Fortaleza, Brazil, were examined: 14 strains from people with diarrhea who lived in an urban community of 2,000 persons, 5 strains from patients in the university hospital, and 7 strains from children in a pediatric hospital. PFGE identified six unique groups of S. flexneri circulating among patients during the 45-month study. Seven strains were further studied for antibiotic resistance plasmid profiles. Three unique antibiotic resistance plasmid profiles were found. Strains collected from the hospitalized patients demonstrated the variety of PFGE and antibiotic resistance patterns in the area. Strains collected from the patients living in the urban community setting demonstrated the persistence of certain PFGE patterns as well as the acquisition of multiple antibiotic resistance plasmids. Effective interventional strategies for such geographic locations as Fortaleza, Brazil, will be more complex than those for single-strain outbreak situations.