Caracterização clonal de cepas de Bordetella pertussis isoladas no Distrito Federal

Bordetella pertussis is a Gram-negative human-restricted bacterium that causes whooping-cough or pertussis, which is the most prevalent vaccine-preventable disease worldwide. The introduction of the pertussis vaccination has affected the bacterial population and epidemiology of the disease. Bordetella pertussis is relatively monomorphic worldwide, but nevertheless, different countries are facing different epidemiological evolutions of the disease. In Brazil, a sudden increase of pertussis cases was observed since 2011. In Distrito Federal, 442 were observed from 2010 to 2014. The aim of this study was to characterize the Bordetella pertussis strains isolated at LACEN-DF during 2012 to 2014 through serotyping and PFGE techniques, besides analyzing the following data: group age and residence of the patients with positive culture for Bordetella pertussis. Ninety two strains were isolated from July 2012 to August 2014: 69 strains were isolated from 16 regions from Distrito Federal (DF), and 23 were from Goiás (GO) and Minas Gerais (MG). The most prevalence were observed among patients from patients with 02 to 04 months of age (40/92), followed by 0 to 01 month of age (28/92). The high prevalence of these infection among babies up to 04 months confirmed the observations in Brazil, in which were recorded 4921 cases in this age range. All the three Bordetella pertussis serotypes were identified among the isolates. Fim2 serotype were the most prevalent (53.23%), followed by Fim3 (31.61%) and Fim2,3 (13.04%). During the period analyzed, there was an alteration of the prevalent serotypes: from July 2013 to July 2014, Fim3 was the most prevalent however from August 2013 to August 2014 the most prevalent serotype was Fim2. Serotyping results suggest that the pertussis outbreak was caused by different two clones from Bordetella pertussis in Brasilia – DF.According to the PFGE in the three years analyzed were characterized 14pulsetypes, with 85% similarity between them. BP.Xba.0039 and BP.Xba.0040 were the most prevalent pulsetype identified. Since August 2013, we observed the increase of BP.Xba.0039 andBP.Xba.0040pulsetypes and the decrease of genetic diversity. These data suggests the selection occurrence of current strains of B. pertussis on the analyzed area.