Pediatric parapneumonic empyema (PPE) has been
increasing in several countries including Spain.
Strepto-
coccus pneumoniae
is a major PPE pathogen; however,
antimicrobial pretreatment before pleural
fl
uid (PF) sam-
pling frequently results in negative diagnostic cultures,
thus greatly underestimating the contribution of pneumo-
cocci, especially pneumococci susceptible to antimicrobial
agents, to PPE. The study aim was to identify the sero-
types and genotypes that cause PPE by using molecular
diagnostics and relate these data to disease incidence
and severity. A total of 208 children with PPE were pro-
spectively enrolled; blood and PF samples were collected.
Pneumococci were detected in 79% of culture-positive and
84% of culture-negative samples. All pneumococci were
genotyped by multilocus sequence typing. Serotypes were
determined for 111 PPE cases; 48% were serotype 1, of 3
major genotypes previously circulating in Spain. Variance
in patient complication rates was statistically signi
fi
cant
by serotype. The recent PPE increase is principally due
to nonvaccine serotypes, especially the highly invasive
serotype 1.