Bacterial Pneumonia. Community acquired usually occurs when immune system is compromised, or when a highly virulent strain is encountered. After microbial agents enter the lung, they multiply and trigger inflammation. Alveoli fill with exudative fluid, and inflammatory cells invade the alveolar septa. The exudate consolidates and is difficult to expectorate. Some patients present with only fever. Other symptoms: crackles, bronchial breath sounds. Chest radiograph can diagnose.
