The Study Of Frequent Pathogenic Bacteria In Lower Respiratory Tract In Bronchial Foreign Bodies In Children

Objective:Using isolation and culture and multiplex PCR methods to test lower respiratory tract secretions and throat swabs in the children with Bronchial foreign bodies and to find out those children complicated with lower respiratory tract infection by bacterial characteristics; finding which kind of methods is better to diagnosis the respiratory tract infections; exploring diagnosis value of the methods to lower respiratory tract infections.Method:Using of bronchoscopy for bronchial foreign bodies in 66 cases of children with lower respiratory tract secretion samples; using sterile cotton swab rubbed pharyngeal to obtain samples to isolation and culture. According to culture results, and selected four kinds of pathogenic bacteria to be tested for heat-resistant Staphylococcus aureus nuclease gene (nuc), Streptococcus pneumoniae-specific encoded autolysin LytA gene, 16SrRNA gene in Haemophilus influenzae, Klebsiella pneumonia White bacilli 16-23SrRNA gene intergenic spacer design specific primers for PCR amplification and optimization of reaction conditions.Result:The lower respiratory tract secretions of 66 cases were cultured positive in 17 clinical samples (25.8%), of which 6 cases of Staphylococcus aureus, Klebsiella pneumoniae in 3 cases,2 cases of Candida albicans, C streptococcus in 1 case, Micrococcus in 1 case, Enterobacter cloacae in 1 case, Escherichia coli in 1 case, Acinetobacter spp in 1 case, genus Pan inl case; Throat swab samples were positive in 7 cases, of which of Staphylococcus aureus in 3 cases, Klebsiella pneumoniae in 2 cases, coagulase-negative staphylococci in 1 case, C streptococcus in 1 case; Achieved by the multiplex PCR method for Staphylococcus aureus, Streptococcus pneumonia, Haemophilus influenzae, Klebsiella pneumoniae, while testing of 14 patients were cultured using conventional isolation and detection of Staphylococcus aureus in 2 cases, Klebsi in 1 case. Multiplex PCR, the results of Haemophilus influenzae samples 7 strains, Streptococcus pneumoniae 4 strains, Staphylococcus aureus 3 strains, and Klebsiella pneumoniae 2 strains.Conclusion:1. Bronchial foreign bodies in children with lower respiratory tract secretions of cultured Gram-positive bacteria, accounting for 52.9%(9/17), among which Staphylococcus aureus 66.7%, throat swab culture results were not consistent with results for bronchial foreign bodies in children.2. The result of multiplex PCR indicated that Haemophilus influenzae and Streptococcus pneumoniae are main pathogens in lower respiratory infections and there is the phenomenon of mixed infection.3. Bronchial foreign bodies in children with the diagnosis of lower respiratory tract pathogens, detection of multiple PCR-positive rate in the isolation and culture, particularly in Streptococcus pneumoniae, Haemophilus influenzae fastidious bacteria, the multiplex PCR method is superior to the method of isolation and culture.4. Multiplex PCR is especially suitable for children who had taken antibiotics before surgery; Multiplex PCR is much more specific and sensitive than isolation and culture..