Bacterial pneumonia is an infection of the lungs caused by bacteria, leading to inflammation and fluid accumulation in the air sacs. Common bacteria responsible for this condition include Streptococcus pneumoniae and Haemophilus influenzae. Symptoms often include cough, fever, chest pain, and difficulty breathing. Diagnosis typically involves a physical examination, chest X-rays, and laboratory tests, such as sputum cultures. Treatment usually consists of antibiotics to eliminate the infection, along with supportive care to help manage symptoms. Vaccines are available to help prevent certain types of bacterial pneumonia, particularly in vulnerable populations.