Acute infection of the lung parenchyma caused by bacteria (e.g., Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila). Signs and symptoms include productive cough, fever, chills, shortness of breath, and chest pain. The disease is bacterial pneumonia (MONDO_0004652, a Monarch Disease Ontology entry). Also known as: Bacteria caused pneumonia, Bacteria pneumonia, gram-negative pneumonia, pneumonia due to other gram-negative bacteria.