<i>Neisseria meningitidis</i> disease-associated clones in Amazonas State, Brazil

<p><b>Background:</b> The aim of this study is to describe the molecular epidemiology of <i>Neisseria meningitidis</i> invasive disease before the introduction of serogroup C conjugate vaccine in Amazonas State in 2010.</p> <p><b>Methods:</b> Meningococcal disease reported cases were investigated in Amazonas State during the period 2000–2010. <i>N. meningitidis</i> isolates (<i>n</i> = 196) recovered from patients were genotyped by multilocus sequence typing (MLST) and sequencing of <i>porB</i>, <i>porA</i>, <i>fetA</i>, <i>fHbp</i> and <i>penA</i>. Antimicrobial susceptibility was determined using E-test.</p> <p><b>Results:</b> In the study period, 948 cases were reported; the incidence was 2.8 for the entire state and 4.8 per 100,000 in the capital of Manaus. Most meningococcal disease was caused by <i>N. meningitidis</i> belonging to ST-32 (72%; 141/196) or ST-103 (21%; 41/196) clonal complexes. Capsular switching (B→C) was suggested within clonal complex (cc) 32. There were 6 (3%; 6/196) strains with intermediate susceptibility to penicillin and a single strain was resistant to rifampicin. Since 2007, serogroup C strains belonging to the cc103 have predominated and case-fatality has increased.</p> <p><b>Conclusion:</b> We demonstrate a high rate of meningococcal disease in Amazonas State, where, like other parts of Brazil, serogroup C replaced serogroup B during 2000s. These data serve as a baseline to measure impact of serogroup C conjugate vaccine introduction in 2010. This study emphasizes the need for enhanced surveillance to monitor changes in meningococcal disease trends following the introduction of meningococcal vaccines.</p>