Objective To study the distribution of pathogenic spectrum in children with severe community-acquired pneumonia(CAP) and bacteria antibiotic resistance.Methods One hundred and ninety-three children with severe CAP were enrolled from Mar 2011 to Feb 2012.Sputum specimens were collected for bacterial culture and drug sensitive test.Meanwhile mycoplasma pneumonia and chlamydia trachomatis were detected by fluorescent quantitative polymerase enzyme technology.Antigen of virus were detected by immunofluorescence assay.Results A total of 96 cases (49.7％) were bacteria positive in 193 children with severe CAP.The top four bacteria strains were klebsiella pneumoniae,staphylococcus aureus,escherichia coli and streptococcus pneumoniae.Most of gram-negative bacteria were resistant to ampicillin,cefazolin,ceftriaxone,ceftazidime,and compound sulfamethoxazole,but were sensitive to piperacillin/tazobactam,imipenem,ciprofloxacin,levofloxacin,amikacin.Gram-positive bacteria were resistant to penicillin and erythromycin,but sensitive to vancomycin.Fifty-three cases (27.5 ％,53/193) were virus Positive,81.1％ of which were less than 1 year old.Respiratory syncytial virus accounted for the most prevalent pathogen,followed by adenovirus,influenza virus A.Mycoplasma pneumoniae were positive in 4 patients (2.1％,4/193),chlamydia trachomatis were positive in 3 patients (1.6％,3/193).Mixed infection was found in 23 cases (11.9％,23/193).There were 14 cases (7.2％,14/193) with undetected pathogens.Conclusion Bacterium is the major pathogen in children with severe CAP and the virus is the second.The initial antibiotics administration of piperacillin/tazobactam or carbapenem and vancomycin should be chosen for severe bacteria pneumonia.

Objective To investigate the significance of expressions of neutrophil and lymphocyte CD11b in children with severe pneumonia.Methods Expressions of neutrophils and lymphocytes CD11b were measured by flow cytometry in 36 children with severe pneumonia( severe pneumonia group),compared with 35 children with mild pneumonia ( mild pneumonia group) and 30 healthy children ( control group).Results In acute stage,expressions of neutrophil CD11b in severe pneumonia group and mild pneumonia group were (90.67 ± 7.03 ) ％ and ( 84.03 ± 5.08 ) ％,respectively,both of which were higher than that in control group [ ( 69.32 ± 5.72 ) ％ ] ( P ＜ 0.05 ).Furthermore,in acute stage,expression of neutrophils CD11b in severe pneumonia group was higher than that in mild pneumonia group (P ＜ 0.05 ).In recovery stage,expressions of neutrophil CD11b in children with severe pneumonia and mild pneumonia were(72.68 ±2.07 ) ％ and (71.45 ± 3.21 ) ％,respectively,which were both lower than those in acute stage ( P ＜ 0.05 ).In acute stage,expression of lymphocyte CD11b of children with severe pneumonia was ( 13.35 ± 6.52 )％,which was lower than that of mild pneumonia group [ ( 19.19 ± 6.47 ) ％ ] ( P ＜ 0.05 ),however,no significant difference was found between severe pneumonia group and control group [ ( 12.42 ± 6.43 ) ％ ] ( P ＞0.05).In recovery period,there was no significant difference in the expression of lymphocytes CD11b between severe pneumonia group [ ( 13.37 ± 4.88 ) ％ ] and mild pneumonia group [ ( 13.78 ± 4.53 ) ％ ] ( P ＞0.05).Conclusion Expressions of neutrophil and lymphocyte CD11 b participate in the pathogenesis of severe pneumonia.Detection of CD11b expression is helpful to diagnose severe pneumonia and predict the prognosis.