The scope of lower respiratory tract infection.

Lower respiratory tract infections (LRTI) are commonly classified as either bronchitis or pneumonia, and these infections are associated with an extremely high morbidity in the community, as well as a high mortality in those patients that require hospitalisation. Therefore, such infections place a huge burden, both economically and as a user of health services, on the entire health care system. The antibiotic treatment of community-acquired pneumonia caused by gram-negative organisms or staphylococci is controversial, and these organisms may cause one-third of the cases of community-acquired pneumonia. Nosocomial pneumonia is caused even more often by gram-negative bacteria, and as such the development of rational and effective antibiotic therapy to cover these organisms is very important.