Infectious Disease Compendium

Cystic fibrosis

Diagnosis

Chronic sinopulmonary infections (Review).

Epidemiologic Risks

The longer they live with the disease, the odder and more resistant the infection.

Microbiology

Early in life they get Staphylococcus aureus and Haemophilus influenzae.

Can get pneumonia from a variety of organisms, the odd ones include: P. aeruginosa, Burkholderia cepacia, M. avium intracellulare, M. abscessus Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, Burkholderia gladioli are some of the rarer organisms that are associated with CF.

Corynebacterium pseudodiphtheriticum as well (PubMed).

Aspergilus: "CF patients with persistent Aspergillus detection have elevated BDG and GM levels which ranged between healthy and invasively infected patients. Serum BDG may be superior to GM and fungal culture in predicting an impaired lung function in CF patients (PubMed). "

Empiric Therapy

Depends in part on prior cultures, therapies, and current gram stains; it usually involves cefepime OR ceftazadime OR carbapenem ie anti-pseudomonal antibiotics.

Aerosolized tobramycin may be of benefit to preserve lung function and prevent infections in stable and mildly ill patients; perhaps inhaled aztreonam is better (Pubmed).

In cystic fibrosis patients, resistance to carbapenems can occur even if the patient has not been treated with these agents (PubMed).

Prior exposure to itraconazole leads to azole resistance in Aspergillus (PubMed).

Macrolides have been used in cystic fibrosis and sepsis where, despite in vitro resistance, the antibiotics improved outcomes. Pseudomonas may be resistant to macrolides in a test tube but when tested in cell culture have efficacy (PubMed).

Pearls

If a young person, like in the mid-twenties presents with Pseudomonas pneumonia out the blue, think cystic fibrosis.

Also, it appears that they have elevated beta-D-glucan for no good reason ie an invasive fungal infection (PubMed).

"...the majority of M. abscessus infections are acquired through transmission, potentially via fomites and aerosols, of recently emerged dominant circulating clones that have spread globally. We demonstrate that these clones are associated with worse clinical outcomes, show increased virulence in cell-based and mouse infection models, and thus represent an urgent international infection challenge (PubMed)."

Last Update: 06/12/18.