Dynamic changes of etiological agents in specimens of sputum in elderly patients with respiratory tract severe infections in ICU

OBJECTIVE To investigate the distributions of etiological agents in specimens of sputum in the patients with the lower respiratory tract infections and dynamic changes after antibiotics administration.METHODS A total of 49 patients were retrospectively surveyed,with lower respiratory tract infections when admitted.Specimens of sputum were collected prior and post to antibiotic therapy.The causative organisms were identified by the routine technique.RESULTS The positive rates of the sputum specimens from the 49 patients were 59.2%,83.7%,and 90.2% on the first day,first week and second week after antibiotic therapy,respectively.Both the positive rates of the sputum specimens after 3 and 4 weeks antibiotic therapy were 100.0%.The most common bacteria during early stage cultures were Candida albicans,Pseudomonas aeruginosa,Klebsiella spp,gram-positive cocci,and Stenotrophomonas maltophilia.While P.aeruginosa,Acinetobacter baumannii and S.maltophilia were frequently detected at late stage.CONCLUSION The positive rates of the sputum specimens increase significantly with the extension of time.multi-factor prognostic analysis suggests renal insufficiency is an independent death risk in the ICU.Cultivation and rational use of antibiotics are important.Active measures should be taken for the prevention of acute renal insufficiency.