An inflammatory condition of the lungs, pneumonia is most often caused by infection, although chemical burns or physical injury can also cause the condition. Infections can be caused by bacteria, viruses, fungi or parasites. Bacterial pneumonia is by far the most common of these infecting agents. Bacterial pneumonia can be treated with antibiotics.The signs of pneumonia often mimic flu symptoms, such as a persistent cough and a fever, often making it difficult for patients to realize early on that they may have a more serious condition, especially as pneumonia can develop after a respiratory infection such as influenza or a cold. However, in people under 65, additional symptoms usually develop quickly.Symptoms of Bacterial PneumoniaA persistent cough, often producing greenish mucus (sputum