Cystic fibrosis is the most common lethal
genetic disease of Caucasians. The disease affects the exocrine gland secretions throughout the body, and as a result, major pathologic changes develop in the pancreas and in the bronchi. Obstruction of the respiratory airways results in
chronic infection, and in time, this leads to progressive deterioration of lung function. In the initial stages of the disease, usually during infancy,
infection with Staphylococcus aureus plays an important role. Hemophilus influenzae
infections are also common. As the disease progresses,
infection with Pseudomonas aeruginosa develops. Exacerbation of bronchopulmonary
infection is often initiated by respiratory viral or mycoplasmal
infection, with superimposed S. aureus and P. aeruginosa
infections contributing to the severity of the
infection. Frequent courses of
antibiotic therapy are usually required, and some patients may have to receive
antibiotics continuously. Oral
cephalosporins,
ampicillin, and the combination of
trimethoprim/sulfamethoxazole are commonly used for relatively mild
infections. In the treatment of exacerbation of
infection, intravenous
penicillinase-resistant
penicillins and anti-Pseudomonas
antibiotics are the drugs of choice. For
Pseudomonas infections,
ticarcillin,
carbenicillin, the ureidopenicillins, and the
aminoglycosides are indicated. The combination of an anti-Pseudomonas
penicillin and an
aminoglycoside are most commonly used. Of the
third-generation cephalosporins,
ceftazidime appears to be the most efficacious. The
quinolones (such as
ciprofloxacin) are also active against P. aeruginosa, and preliminary studies of these drugs in patients with
cystic fibrosis appear to indicate that they are as efficacious as the already available
antibiotics. In many centers, Pseudomonas cepacia has emerged as a serious problem in patients with
cystic fibrosis. This organism tends to develop resistance to multiple
antibiotics. In some centers,
infection with P. cepacia has been associated with a severe, frequently fatal,
pneumonia.