Bacterial spectrum and drug resistance of pathogens causing nosocomial lower respiratory tract infections

OBJECTIVE To explore the bacterial spectrum and drug resistance of the pathogens causing lower respiratory tract infections so as to provide reference for the clinical use of antibiotics.METHODS The sputum specimens were collected from the hospitalized patients with lower respiratory tract infections from Jan 2010 to Jan 2012.The eligible sputum specimens were inoculated to the blood agar plate and the MacConkey tablet for the bacterial culture for 24-48 hours.According to the National Clinical Laboratory Operation Standards,the bacteria were isolated and identified with API identification strips of Bio-Merieux,France.The drug susceptibility testing was performed by using the K-B method,the results were judged by referring to the standards for the operation of K-B for drug susceptibility testing by the NCCLS,2002 edition.RESULTS A total of 873 strains of pathogens were isolated from 1034 eligible sputum specimens with the detection rate of 84.4%,including 517(59.22%) strains of gram-negative bacteria,215(24.63%) strains of fungi,and 141(16.15%) strains of gram-positive bacteria.The results of antimicrobial sensitivity testings showed that the drug resistance rate of the gram-negative bacteria was the lowest to imipenem,followed by amikacin.The gram-positive bacteria were highly sensitive to vancomycin,reaching up to 100.00%.CONCLUSION The gram-negative bacilli are the main pathogens causing the lower respiratory tract infections,followed by fungi and gram-positive bacteria.The bacterial resistance becomes increasingly serious,thus it is necessary to reasonably use antibiotics on the basis of drug susceptibility testing result.