Over time, CF patients' lungs become colonized with bacteria usually acquired from the environment. People without CF are normally immune to these bacteria, but the bacteria can be transferred between CF patients. Bacteria such as Burkholderia cepacia are the most likely suspects.

Everyone inhales bacteria, but the lungs are usually protected from infection by a thin blanket of mucus that coats the lining of the lungs and traps bacteria, which are then transported out of the lungs. But the thick, sticky mucus in the lungs of CF patients allows the bacteria to survive. Pseudomonas aeruginosa and Staphylococcus aureus bacteria typically infect CF patients, and along with other bacteria can become resistant to antibiotics.

Infection control is defined as "strategies that prevent the acquisition and spread of bacteria." The most important prevention measure is frequent hand-washing with soap and water or alcohol-based cleaners. Proper cleaning of nebulizers and other equipment can also prevent the acquisition of bacteria. 

The best way to minimize the spread of bacteria between CF patients is to prevent prolonged direct contact. Coughing allows droplets carrying bacteria to leave the lungs of patients with CF. Since these droplets do not travel more than 3 feet, maintaining a distance of 3 to 6 feet from other CF patients should minimize the risk of spreading CF pathogens.

Antibiotic-resistant bacteria are the most threatening, including Burkholderia cepacia, Methicillin-resistant Staphylococcus aureus (MRSA) and multiple drug-resistant Pseudomonas aeruginosa (MDR-Pa). Most CF centers have specific policies for managing patients that are colonized with these organisms.

For more information see Stopping the Spread of Germs (PDF)published by the CF Foundation.