Laboratory-based, 2-year surveillance of pediatric parapneumonic pneumococcal empyema following heptavalent pneumococcal conjugate vaccine universal vaccination in Madrid.
BACKGROUND
In October 2006, the heptavalent pneumococcal conjugate vaccine was included in the Madrid vaccination calendar, warranting serotype (St) surveillances in pneumococcal pediatric parapneumonic empyema (PPE).


METHODS
A prospective 2-year (May 2007-April 2009) laboratory-confirmed PPE surveillance was performed in 22 hospitals. All isolates (for serotyping) and culture-negative pleural fluids were sent to the reference laboratory for polymerase chain reaction (PCR) analysis.


RESULTS
We identified 138 PPEs. Pneumococcal etiology was confirmed in 100 cases: 38 by culture, 62 by PCR. Mean age was 44.64 ± 26.64 months; 51.0% were male. Similar pneumococcal PPE distribution was found by age: 21% to 28% in <24, ≥24-<36, ≥36-<60, and ≥60 months. PPE-associated Sts were St 1 (38%), St 5 (15%), St 19A (11%), St 7F (9%), St 3 (8%), and others (19%). St 1 was the most common in >36 months, with similar rates to St 19A in <24 months (≈30%). In ≥24-≤36 months, St 3 (21.7%), St 1 and St 5 (17.4% each) were the most frequent. No differences in demographic data, vaccination status, length of hospitalization, and outcome were found between culture-negative (PCR positive) and culture-positive PPE patients, with significantly higher percentages of St 1 and St 5 in culture-positive PPEs. Total rates of St 1 (38%), St 5 (15%), and St 7F (9%) would have been over-represented considering only positive-culture PPEs (n = 38), by increasing to 52.6% (St 1), 23.7% (St 5), and 10.5% (St 7F). The 13-valent pneumococcal conjugate vaccine would cover 84.0% of Sts causing PPEs.


CONCLUSIONS
PCR is essential for determining the specific etiology of PPE.
Microbiology Department, Hospital Clínico San Carlos, Madrid, Spain.
Juan
J
Picazo
Jesus
J
Ruiz-Contreras
Juan
J
Casado-Flores
Sagrario
S
Negreira
Fernando
F
Del Castillo
Teresa
T
Hernández-Sampelayo
Mercedes
M
Bueno
Cristina
C
Calvo
Esther
E
Ríos
Cristina
C
Méndez
D002675:Child, Preschool; D004653:Empyema / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D008297:Male; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D012703:Serotyping; D013030:Spain / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification*
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines