Etiological Comparison Of Lower Respiratory Tract Infection Between Patients With Asthma Chronic Obstructive Pulmonary Disease Overlap(ACO) And Patients With Chronic Obstructive Pulmonary Disease(COPD)

Objective:To investigate the etiological distribution of lower respiratory tract infection in patients with asthma chronic obstructive pulmonary disease(ACO)and chronic obstructive pulmonary disease(COPD).Methods:From June 2017 to December 2019,the clinical data of ACO patients and COPD patients in the same period were collected from the respiratory department of the Second Hospital of Hebei Medical University,and the laboratory indexes of the two groups were analyzed.Results:1.There was no significant difference in gender and age between ACO group and COPD group.2.In ACO group and COPD group,the distribution of pathogenic bacteria in lower respiratory tract was mainly Gram-negative bacteria.134 strains were collected in ACO group,of which 35 strains(26.12%)were Klebsiella pneumoniae,28(20.90%)Pseudomonas aeruginosa,22(16.42%)Acinetobacter baumannii,11(8.20%)Enterobacter cloacae,9(6.71%)Escherichia coli,2(1.49%)Serratia marcescens,1(0.75%)Acin etobacter haemolyticus.134 strains were collected in COPD group,of wh ich 50 strains(37.31%)were Pseudomonas aeruginosa,31 strains of Kle bsiella pneumoniae(23.13%),19 strains of Acinetobacter baumannii(14.18%),9 strains of Escherichia coli(6.72%),4 strains of Enterobacter cl oacae(2.99%),4 strains of Haemophilus parainfluenzae(2.99%),2 strains of Enterobacter aerogenes(1.49%),including 1 Staphylococcus aureus(0.75%)and 2 Streptococcus pneumoniae(1.49%).3.There were differences in the proportion of fungal infection between the two groups.In ACO patients,Aspergillus accounted for 16 strains(11.94%)and Candida albicans 6 strains(4.48%);in COPD patients,Candida albicans was the main strain,accounting for 7 strains(5.22%),3 strains(2.24%)and 2 strains(1.49%)of Candida albicans.4.There was no significant difference in the percentage of neutrophils between the two groups after infection with pathogenic bacteria.The absolute value of eosinophils in ACO group was higher than that in COPD group,and the difference between the two groups was statistically significant(P < 0.05).5.In ACO group,the absolute value of eosinophils in patients with fungal infection was higher than that in patients with bacterial infection.In COPD group,there was no significant difference in eosinophil elevation between fungal infection and bacterial infection.Conclusion:1.In acute exacerbation period,Gram-negative bacteria were the main pathogens,followed by fungi,and Gram-positive bacteria were the least.2.The types and proportions of pathogens in lower respiratory tract infection of patients with acute exacerbation of ACO are different from those of patients with acute exacerbation of COPD.3.The absolute value of eosinophils was higher in patients with acute exacerbation of ACO after fungal infection than that after bacterial infection,suggesting that patients with ACO may be sensitized after fungal infection,leading to exacerbation of the disease.