[Bacterial etiology of pneumonia in hospitalized children: combined detection with culture and polymerase chain reaction].

Objective: Bacterial cultures from respiratory aspirate or sputum have been the conventional diagnostic method for pneumonia, but the results of culture was often affected by early extensive use of antibiotics, sample collection and delivery. The objective of this study was to explore application of the combined detection of culture and polymerase chain reaction (PCR) assay in hospitalized children with pneumonia.
Methods: Totally 187 hospitalized children with pneumonia were enrolled. The age of the patients ranged from 1 month to 10 years, 124 were male, 63 female; 175 of the patients received antibiotics treatment before admission. Deep respiratory aspirate sample from patients was cultured by Streptococcus pneumoniae selective plate, Hemophilus influenzae selective plate and conventional plate. The aspirate samples were also amplified for DNA of 14 bacteria with target enriched multiplex polymerase chain reaction (Tem-PCR) and detected with Luminex xMAP technology platform.
Results: The total positive rate by bacterial culture was 40.1% (75/187), of which 17.1% (24/187) were Hemophilus influenzae b, 8.6% (16/187) were Escherichia coli, 6.4% (12/187) were Klebsiella pneumoniae, 4.8% (9/187) were Staphylococcus aureus, 3.7% (7/187) were Streptococcus pneumoniae, 1.6% (3/187) were Pseudomonas aeruginosa, 1.1% (2/187) were Acinetobacter baumannii, and 1.1% (2/187) were Enterobacter cloacae. The total positive rate by combined detection of culture and Tem-PCR assay were 78.6% (147/187), of which 28.9% (54/187) were Hemophilus influenzae b, 19.3% (36/187) were Streptococcus pneumoniae, 8.6% (16/187) were Escherichia coli, 6.4% (12/187) were Klebsiella pneumoniae, 5.9% (11/187) were Staphylococcus aureus, 5.9% (11/187) were Acinetobacter baumannii, 2.7% (5/187) were Pseudomonas aeruginosa, and 1.1% (2/187) were Enterobacter cloacae.
Conclusion: The Tem-PCR assay may increase the detection rate of Hemophilus influenzae b, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. The Combined detection may increase the positive rate of bacterial pathogens in hospitalized children with pneumonia, and the results might reflect the real patterns of bacterial etiology. The Tem-PCR needs further improvement for diagnosis of Escherichia coli and Klebsiella pneumoniae.