Clinical characteristics of respiratory tract bacterial infections in patients with chronic obstructive pulmonary disease

OBJECTIVE To explore the characteristics of respiratory tract bacterial infections in patients with chronic obstructive pulmonary disease(COPD)to provide guidance for treatment of the infections.METHODS Totally 3 057 COPD patients,who were treated from Mar 2008 to Jan 2013,were enrolled in the study,including 672 cases of respiratory tract bacterial infections,then the data of the subjects were retrospectively analyzed, totally 103 subjects with stable condition were selected from the 672 patients,the sputum culture and drug susceptibility testing were performed,the distribution and drug resistance of pathogens were analyzed,the identification of strains was conducted with the use of VITEK-260 automatic bacteria identification system of BioMerieux,France,and the drug susceptibility testing was performed by using K-B disk diffusion method. RESULTS Of totally 3057 cases of COPD,the respiratory tract bacterial infections occurred in 672 cases with the infection rate of 22.0%.The clinical manifestations of the 103 COPD patients complicated with respiratory tract bacterial infections were the chronic cough(97 cases),expectoration(83 cases),shortness of breath(66cases), and chest tightness(54cases),accounting for 94.17%,80.58%,64.08%,and 52.43%,respectively.A total of 192strains of pathogens were isolated from the sputum specimens,including 134(69.79%)strains of gramnegative bacilli and 58(30.21%)strains of gram-positive cocci;the Pseudomonas aeruginosa(50.74%)was the predominant species of gram-negative bacilli,followed by the Klebsiella pneumoniae(19.27%)and Escherichia coli(11.49%);the Staphylococcus aureus(21strains)was the most common species of gram-positive cocci, accounting for 10.94%.The drug resistance rates of the K.pneumoniae,P.aeruginosa,and E.coli to imipenem and meropenem were significantly lower than those to other commonly used antibiotics,which were 0,11.1%, and 0,respectively,the differences were statistically significant(P0.05).CONCLUSION The gram-negative bacilli are dominant among the pathogens causing the respiratory tract bacterial infections in the COPD patients, among which the P.aeruginosa,K.pneumoniae,and E.coli are the most common species;imipenem and meropenem can be chosen for the treatment of refractory infections.