Distribution and antimicrobial resistance of pathogenic bacteria causing lower respiratory tract infections

OBJECTIVE To investigate the distribution of bacteria isolated from patients with lower respiratory tract infections and analyze the result of drug susceptibility testing so as to provide basis for the reasonable clinical use of antibiotics.METHODS The conventional bacterial culture was performed for the sputum specimens obtained from 520 patients with lower respiratory tract infections,the identification and the drug susceptibility testing were performed for the isolated pathogens.RESULTS Of 520 strains of pathogens isolated,the gram-negative bacilli accounted for 70.6%(367 strains),the gram-positive cocci accounted for 16.0%(83 strains),and the fungi accounted for 13.4%(70 strains).The top three species of the gram-negative bacilli were Klebsiella pneumoniae(112 strains,21.5%),Escherichia coli(54 strains,10.4%) and Enterobacter cloacae(45 strains,8.7%);the top three species of gram-positive cocci were Staphylococcus haemolyticus(35 strains,6.7%),Staphylococcus aureus(22 strains,4.2%) and Staphylococcus epidermidis(16 strains,3.1%).The gram-negative bailli were highly sensitive to carbapenems.The gram-positive cocci were highly sensitive to linezolid,vancomycin,quinupristin/dalfopristin,nitrofurantoin and chloramphenicol.CONCLUSION The various species of pathogens causing the lower respiratory tract infections vary significantly in the drug resistance to the same antibiotic.It is necessary to use antibiotics on the basis of drug susceptibility testing result so as to reduce the drug resistant strains.