“…Such agents include Pneumocystis carinii/jiroveci, Mycobacterium tuberculosis, other mycobacteria and Nocardia. (1)(2) In the absence of an etiological diagnosis, broad-spectrum antimicrobial treatment regimens tend to be used and are frequently extended over the course of the treatment if a satisfactory response is not obtained. These treatments expose the patients to side effects from a great number of antibiotics, increase the risk of nosocomial infection, facilitate the emergence of resistant strains, and are costly.…”