Pathogenic Bacteria Distribution Of Children With Bacterial Pneumonia And Changes Of Immune Function

BackgroundPneumonia is still the leading cause of death in children under 5 years old in China.Bacteria are the main pathogens causing pneumonia,so understanding the distribution characteristics and drug resistance of pathogenic bacteria in children with bacterial pneumonia in different areas has great significance,so as to guide the rational use of antibiotics in clinical practice,improve the prognosis of children with bacterial pneumonia.The occurrence of infectious pneumonia is also closely related to the immune dysfunction of the body expect the direct infection of pathogens,therefore,analyze the relationship between the changes of immune function and the severity of illness in children with bacterial pneumonia is very important for guiding clinical treatment and evaluating the prognosis of children.Objective(1)Analysis of the pathogenic bacteria distribution and drug resistance of 246 children with bacterial pneumonia,in order to guide clinicians in this region to rationally apply antibacterial drugs.(2)Explore the changes of cellular and humoral immune function in children with bacterial pneumonia,and analyze the correlation between immune function and severe pneumonia.Methods(1)Using prospective research methods,246 children with bacterial pneumonia treated in the department of pediatrics of shangqiu first people's hospital from January 2017 to December 2019 were selected as the research objects,collected the lower respiratory tract secretions such as sputum,alveolar lavage fluid,bronchial brush and bronchial secretions,than carried out bacterial culture,strain identification and susceptibility test in vitro for the cultured strain.(2)The 246 children with bacterial pneumonia were divided into mild pneumonia group(n=197)and severe pneumonia group(n=49)according to the severity of pneumonia,another 50 healthy children who came from shangqiu first people's hospital for physical examination during the same period were selected as the control group,the proportion of peripheral blood T lymphocyte subsets(CD3+,CD4+,CD8+)and the levels of serum humoral immune function-related indicators(IgA,IgG,IgM)were compared between the three groups,the multivariate Logistic regression analysis was used to analyze the correlation between immune indexes and severe pneumonia.Results(1)A total of 1276 samples of lower respiratory tract secretions were collected from 246 children with bacterial pneumonia,most of sputum and bronchial secretions,accounting for 57.68%and 40.05%,respectively.(2)A total of 468 strains of pathogenic bacteria were cultured in 1276 samples of lower respiratory tract secretions,in which the Gram-negative bacilli accounted for 85.47%,Gram-positive cocci accounted for 14.53%,multiple bacterial infections account for 1.18%.(3)Klebsiella pneumoniae was the most in the Gram-negative bacilli,accounting for 21.58%,than Acinetobacter baumannii,Pseudomonas aeruginosa,Escherichia coli,accounting for 18.59%,13.89%and 9.19%,respectively.Staphylococcus aureus was the most in the Gram-positive cocci,accounting for 6.41%,than Streptococcus pneumoniae,accounting for 3.42%.(4)The susceptibility results in vitro suggest that both Staphylococcus aureus and Streptococcus pneumoniae were very sensitive to mupirocin,linezolid,vancomycin and telagione,the resistance rates for penicillins,ciprofloxacin,aztreonam,cephazolin,cefazolin and clavulanic acid/cefotaxime were all higher than 50%.(5)The susceptibility results in vitro suggest that Klebsiella pneumoniae had higher resistance rates to penicillins,cephalosporins,ampicillin/sulbactam,sulfamethoxazole/trimethoprim and aminoglycoside except for amikacin,it was more sensitive to carbapenems.Acinetobacter baumannii had higher resistance rates to penicillins,aminoglycosides,ampicillin/sulbactam,fluoroquinolones and cephalosporins,but it was more sensitive to cefoperazone and carbapenems.Pseudomonas aeruginosa had higher resistance rates to penicillins,cephalosporins and sulfamethoxazole/trimethoprim,the resistance rate for carbapenems was 40%,it was more sensitive to aminoglycosides.Escherichia coli showed high resistance to penicillins,cephalosporins,ampicillin/sulbactam,sulfamethoxazole/trimethoprim and aminoglycoside except for amikacin,it was more sensitive to cefoperazone/sulbactam and carbapenems.In addition,all of the above 4 strains were sensitive to clavulanic acid/ceftazidime and clavulanic acid/cefotaxime.(6)Compared with the control group,the proportion of CD3+,CD4+and CD4+/CD8+in peripheral blood decreased significantly,the proportion of CD8+increased significantly in children with mild pneumonia group and severe pneumonia group(P<0.01);compared with mild pneumonia group,the proportion of CD3+,CD4+and CD4+/CD8+in peripheral blood decreased significantly,the proportion of CD8+increased significantly in children with severe pneumonia group(P<0.01).(7)Compared with the control group,the levels of IgA,IgG and IgM in serum decreased significantly in children with mild pneumonia group and severe pneumonia group(P<0.01),and the levels of IgA,IgG and IgM in serum of the severe pneumonia group were significantly lower than the mild pneumonia group(P<0.01)(8)Multivariate Logistic regression analysis showed that CD4+/CD8+and levels of IgA and IgG were associated with the occurrence of severe pneumonia(all P<0.05);however,the gender,age,disease course,the proportion of CD3+,CD4+,CD8+and IgM level had no correlation with the occurrence of severe pneumonia(all P>0.05).Conclusion(1)Gram-negative bacilli is the main pathogenic bacteria causing bacterial pneumonia in children in this area,in which Klebsiella pneumoniae is the main pathogenic bacteria;Staphylococcus aureus is the main Gram-positive pathogenic bacteria.(2)The drug resistance of bacterial pneumonia pathogens in this area is still very severe.Amikacin,carbapenems,clavulanic acid/ceftazidime and clavulanic acid/cefotaxime can be used for pneumonia caused by Klebsiella pneumoniae and Escherichia coli,E.coli can also be treated with cefoperazone/sulbactam;Clavulanic acid/ceftazidime and clavulanic acid/cefotaxime can be used for pneumonia caused by Acinetobacter baumannii and Pseudomonas aeruginosa,Acinetobacter baumannii can also be treated with carbapenems;Mupirocin,linezolid,vancomycin and tiramucin can be used for pneumonia caused by Staphylococcus aureus and Streptococcus pneumoniae.(3)The immune function of children with bacterial pneumonia is significantly reduced,and the more serious the disease,the more obvious the decrease in immune function.(4)The CD4+/CD8+and the levels of IgA and IgG are associated with severe pneumonia,the lower of CD4+/CD8+and the levels of IgA and IgG,the higher the risk of severe pneumonia.