Unusual Gram-negative bacteria cause more severe bacterial meningitis than the three classical agents in children

Aim To compare the characteristics, mortality and sequelae at hospital discharge of childhood bacterial meningitis (BM) caused by the three "classical" agents Neisseria meningitidis, Haemophilus influenzae or Streptococcus pneumoniae versus BM due to other aetiology in Finland, Latin America and Angola. Methods This observational study is a secondary analysis of data from five prospective treatment trials on non-neonatal BM in Finland, Latin America and Angola in 1984-2017. Results Of the 1568 cases, 1459 (93%) were caused by the classics, 80 (5%) by other Gram-negative and 29 (2%) by other Gram-positive bacteria. Nonclassical Gram-negative disease was encountered especially in Angola (p < 0.0001). Overall, children in the nonclassical group presented later for treatment and were more often underweight and anaemic (p < 0.001). In multivariate analysis, even if the area was strongest predictor of poor outcome, nonclassical Gram-negative BM increased the odds for death twofold and the odds for death or severe sequelae 2.5-fold. Conclusion BM of a nonclassical aetiology is a particularly severe disease affecting especially Angolan children poorly armoured to fight infections. Since vaccinations are diminishing the role of classical agents, that of nonclassical agents is growing.