Croup
Bacterial croup includes laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. Corynebacterium diphtheriae causes laryngeal diphtheria; bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis come from a virus infection, followed by a bacteria infection. The most common bacteria that cause croup areStaphylococcus aureus, Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis.