Molecular analysis improves pathogen identification and epidemiologic study of pediatric parapneumonic empyema.
BACKGROUND
Parapneumonic empyema (PPE) is an increasingly common complication of bacterial pneumonia. Epidemiologic study is complicated by the low frequency of positive cultures. We sought to describe the epidemiology of PPE in children using molecular analysis of pleural fluid.


METHODS
We performed molecular testing for bacterial pathogens using archived pleural fluid from children hospitalized in 2009 with PPE. Real-time polymerase chain reaction (PCR) to detect Streptococcus pneumoniae, Staphylococcus aureus (including methicillin-resistant), Streptococcus pyogenes, Haemophilus influenzae, and Mycoplasma pneumoniae as well as PCR-based serotyping of S. pneumoniae was performed. Demographic, laboratory, and microbiologic data were abstracted.


RESULTS
Pleural fluid specimens from 63 children were available for PCR. By culture, a pathogen was isolated from blood and/or pleural fluid in 22 (35%) patients, with S. pneumoniae in 15 (24%), S. pyogenes in 3 (5%), and methicillin-resistant Staphylococcus aureus in 4 (6%). By PCR, a pathogen was detected in 53 (84%), including S. pneumoniae in 45 (71%). Compared with culture, PCR testing significantly increased detection of any pathogen (35% vs. 84%; P < 0.001) and of S. pneumoniae (24% vs. 71%; P < 0.001). Serotype 7F was the most common pneumococcal serotype detected. Comparison of culture-negative to culture-positive disease showed differences in both the pathogen profile and clinical outcomes.


CONCLUSIONS
Molecular analysis of pleural fluid more than doubled the detection of pathogens causing PPE. S. pneumoniae was the most common cause of both culture-positive and culture-negative PPE, although serotype distribution and outcomes differed.
Department of Pediatrics, University of Utah, Salt, Lake City, UT, USA. anne.blaschke@hsc.utah.edu
Anne J
AJ
Blaschke
Caroline
C
Heyrend
Carrie L
CL
Byington
Ignacio
I
Obando
Isabel
I
Vazquez-Barba
Elizabeth H
EH
Doby
E Kent
EK
Korgenski
Xiaoming
X
Sheng
Mark A
MA
Poritz
Judy A
JA
Daly
Edward O
EO
Mason
Andrew T
AT
Pavia
Krow
K
Ampofo
D000293:Adolescent; D001424:Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D016724:Empyema, Pleural / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D015995:Prevalence; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D013297:Streptococcus pyogenes / Q000302:isolation & purification