Pediatric parapneumonic empyema, Spain

Abstract

Pediatric parapneumonic empyema (PPE) has been increasing in several countries including Spain. Streptococcus pneumoniae is a major PPE pathogen; however, antimicrobial pretreatment before pleural fluid (PF) sampling frequently results in negative diagnostic cultures, thus greatly underestimating the contribution of pneumococci, especially pneumococci susceptible to antimicrobial agents, to PPE. The study aim was to identify the serotypes 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 prospectively 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 significant by serotype. The recent PPE increase is principally due to nonvaccine serotypes, especially the highly invasive serotype 1.

Figure 1

Annual number of pediatric parapneumonic empyema (PPE) cases among children <14 years of age admitted to Seville and Malaga hospitals from 1998 to June 2006 (combined prospective and retrospective data) and among children <18 years of age admitted to a Barcelona hospital from October 2003 through June 2006. *October 1, 2003, through December 31, 2003.

Figure 2

Microbiologic characteristics of pleural fluid (PF) specimens from pediatric parapneumonic empyema (PPE) case-patients. *Streptococcus pyogenes (6), Staphylococcus aureus (3), Mycobacterium tuberculosis (2), Escherichia coli (1), Streptococcus mitis (1), Peptostreptococcus spp. (1). †Pleural fluids analyzed by PCR included 2 samples that were ply negative but wzg positive. ‡18 partially genotyped by multilocus sequence typing (MLST) (>3 alleles), as DNA concentration was too low for reliable PCR amplification and sequencing.