Staph infections Staphylococcus aureus is so common that it is hard to appreciate the full range of its virulence. S. aureus infections are especially common in hospitals. Recently, scientists have begun to understand how virulence factors in S. aureus are regulated. So up to 10,000 microbes per day enter lungs. Those that do reach alveoli are quickly eaten by macrophages.
Diseased hosts have difficulty breathing, cough frequently.
Examples of airborne pathogens Diphtheria . Caused by Corynebacterium diphtheriae . See lecture notes from Univ. of Wisconsin. Bacterial meningitis . See CDC fact sheet .