Sensitization to aztreonam and cross-reactivity with other beta-lactam antibiotics in high-risk patients with cystic...

Area of Science:

• Immunology
• Pharmacology
• Clinical Medicine

Background:

• Patients with cystic fibrosis (CF) often have allergies to beta-lactam antibiotics (BLAs).
• Investigating aztreonam's safety and immunogenicity in this high-risk group is crucial.

Purpose of the Study:

• To assess the immunogenicity, allergenicity, and cross-reactivity of aztreonam in CF patients with prior BLA allergies.
• To determine the risk of allergic reactions and sensitization to aztreonam in this population.

Main Methods:

• Skin tests (STs) and serologic testing (IgE, IgG) were used to evaluate reactions to penicillin, cephalosporins, and aztreonam.
• 21 CF patients with documented allergies to other BLAs were enrolled.

Main Results:

• 90% of patients showed positive skin tests to other BLAs.
• Initially, 20 out of 21 patients had negative aztreonam skin tests.
• Four patients developed sensitization to aztreonam after treatment, with allergic reactions observed in three.
• No aztreonyl-specific IgE or IgG antibodies were detected, even in allergic patients.

Conclusions:

• Aztreonam is generally well-tolerated in CF patients allergic to other BLAs, with low detected immunogenicity.
• Preexisting cross-reactivity (5%) and sensitization rates (20%) warrant caution when prescribing aztreonam to BLA-allergic CF patients.