Patients who have penA labels are treated with non-penicillin antibiotics and receive more antibiotics when compared with patients without penA after formal allergy assessments, >90% of people with a penA label are found not to be allergic Antimicrobial stewardship policies now advocate assessment to identify and remove incorrect penA labels

Eighteen studies compared AMR outcomes in participants with and without penA, and the rest investigated the impact of beta-lactam allergy or any antibiotic allergy on AMR outcomes PenA labels were also associated with vancomycin-resistant enterococci (three of five studies)

There was limited evidence on the impact of penA on extended-spectrum beta-lactamase-producing Enterobacterales and resistant Streptococcus pneumoniae.