Abstract: The aim was to study the changes on the distribution and drug resistance of the bacteria in patients with the nosocomial lower respiratory tract infection (LRTI) in respiratory ward.The sputum's culture of the patients with the nosocomial LRTI in respiratory ward from 1998 to 2002 was studied with MIC methods.Results: 430 strains were isolated, 73% of which were Gram negative bacillus (GNB) and decreased gradually; 64% of GNB were non fermenters and increased.27% of which were Gram positive bacteria (GPB) and increased; 32% of GPB were S.aureus (SA) and increased, 26% of GPB were methicilin resistant SA (MRSA) and increased.Drug-resistant was growing, only few drugs, such as vancomycin to GPB (0) and Imipenem to GNB (17%), kept lower resistance.Conclusions: The distribution and drug resistance of the bacteria had been changing with time and antibiotics use, nosocomial pathogens have shifted away from easily treated bacteria toward more resistant bacteria.Few drugs, such as vancomycin and imipenem and so on, can be selected to treat nosocomial pathogens.Integrated management is a method to improve it.

Key words: nosocomial infection, lower respiratory tract infection, bacteria, drug resistance