Diagnosis of acute community acquired pneumonia is based on the history, physical examination, and chest x-ray. With respect to diagnosis, the clinician should ask, (1) Is the problem pneumonia or something else? (2) Is the pneumonia often treated empirically with a macrolide (erythromycin, clarithromycin, or azithromycin), a "respiratory quinolone" (levofloxacin, moxifloxacin, gatifloxacin, or gemifloxacin) or doxycycline. 4. Concern has expressed that use of quinolones as monotherapy for pneumonia may promote the emergence of resistant strains. However, the quinolones are more reliable than the macrolides and doxycycline against pneumococcal strains that exhibit reduced susceptibility to penicillin G. 5. Appropriate diagnostic studies for patients with moderately-severe to severe pneumonis include sputum Gram's stain and culture (for those patients who expectorate purulent sputum), blood cultures, and acute serum sample, and --in some circumstnaces--urinary antigen test for Legionella pneumophila. 6. Appropriate initial therapy for patients requiring hospitalization includes a third-generation cephalosporin (such as ceftriaxone or cefotaxime) plus a macrolide or a quinolone.
