The prevalences were distributed with typical bacterial pneumoniain 20.7%, viral pneumonia in 24.7%, mixed bacterial - viral pneumonia in 31.6%. Typical bacterial pneumonia (included bacterial infections and bacterial - viral coinfections) had higher proportion in prolonged duration of symptoms before admission, fever ≥ 39oC, total WBC count > 22000 / mm3, elevated percentage of neutrophil, presence of band forms, CRP > 35mg / L (p<0.05), presence of lobar or segmental consolidation on chest X - ray, association with pleural effusion than viral pneumonia.