RESUMEN
BACKGROUND: An outbreak of serogroup C meningococcal disease (MD) that involved employees from an oil refinery occurred in Paulínia, from March to June 2010, and spread to the community of Cosmópolis, both situated in São Paulo State, Brazil. The aim of this study was to describe the epidemiological and laboratory aspects, and the control measures that were implemented. METHODS: Descriptive and molecular epidemiological analysis was used to define the extent of the outbreak and the common risk factors among outbreak related cases. Vaccination initiative targeted the employees from the oil refinery and the community-based individuals. RESULTS: A total of six outbreak-related cases of MD in the oil refinery and 12 cases in the city of Cosmópolis, São Paulo State occurred in a three-month period. All 18 MD cases were confirmed as serogroup C either by culture, real time polymerase chain reaction (RT-PCR), or counterimmunoelectrophoresis (CIE). The meningococcal isolates (n=15) had the phenotype C:23:P1.14-6 and showed close genetic relationship by pulsed field gel electrophoresis (PFGE). Multilocus sequence typing (MLST) characterization showed that the clones were ST 3780, ST-103 complex. The isolates were susceptible to the antibiotics tested. Vaccination was administered to 15,848 persons at the oil refinery and 18,571 persons of the community. CONCLUSIONS: The molecular characterization of the Neisseria meningitidis (N. meningitidis) strains, and the efficient investigation and the prompt measures implemented were essential for controlling the disease in the region.