 "Staphylococcus aureus", "Haemophilus influenzae", and "Pseudomonas aeruginosa" are the three most common organisms causing lung infections in CF patients.The most common infection involves bacterial strain mutation to form a biofilm-forming and sustaining mucoid strain on the lung epithelium, which can result in downstream mechanisms that progress the infection.In addition to typical bacterial infections, people with CF more commonly develop other types of lung disease.