IV levofloxacin is effective if the patient’s lung infection is due to a bacterial or atypical pathogenic bacteria. If the patient’s intrapulmonary infection is caused by a viral infection or a fungal infection, levofloxacin is ineffective. Therefore, when a patient is diagnosed with an intrapulmonary infection, tests need to be completed to evaluate the possible causative organisms. If the patient’s blood work shows elevated white blood cells, neutrophils, and neutrophil percentage, along with increased C-reactive protein and calcitoninogen, a bacterial infection is clinically considered. If the patient presents with a recent quadruple or more elevated mycoplasma antibody, consider a mycoplasma infection. If the patient has decreased white blood cells, elevated lymphocytes, and normal C-reactive protein, as well as interstitial changes in lung CT and positive viral antibodies, a viral pneumonia is considered clinically.