Supplementary Material for: Microbial Isolates and Antimicrobial Resistance Patterns in Adults with Inborn Errors of Immunity: A Retrospective Longitudinal Analysis of Sputum Cultures

Introduction: Individuals with inborn errors of immunity (IEI) are at increased risk of respiratory infection and frequently receive prolonged broad-spectrum antibiotics, leading to antibiotic resistance. To identify respiratory pathogens and antibiotic resistance patterns in IEI patients.
Methods: We retrospectively studied 36 IEI patients with positive bacterial growth in sputum cultures between 2014 and 2023. Data covered hospitalizations, respiratory infections, yearly antibiotic prescriptions, past sputum cultures, and antibiotic sensitivities. Patients with primary ciliary dyskinesia (PCD) and bronchiectasis served as a control group.
Results: A total of 314 sputum cultures were analyzed from patients with IEI, alongside 585 cultures from individuals with PCD, and 113 cultures from patients with bronchiectasis. Patients with IEI had a median age of 23.5 years, with 61% male. The study compared the differences in bacterial isolates from sputum cultures and antibiotic resistance between patients with IEI and the control groups. The most common bacterial isolates across all groups were Haemophilus influenzae (159 isolates in IEI vs. 314 in PCD and 26 in bronchiectasis), Pseudomonas aeruginosa, and Streptococcus pneumoniae. In IEI patients, 992 symptomatic respiratory exacerbations and 43 pneumonia-related hospitalizations were recorded. Notably, Haemophilus influenzae in IEI patients showed high resistance rates to cefuroxime (82%), amoxicillin/clavulanic acid (66%), trimethoprim/sulfamethoxazole (59%), and ampicillin/sulbactam (49%). Pseudomonas aeruginosa in IEI patients displayed significant resistance to ciprofloxacin (85%), ceftazidime (42%), and aminoglycosides (23-33%). Additionally, all Streptococcus pneumoniae isolates in IEI patients were tetracycline-resistant, with high resistance rates to penicillin, clindamycin, and erythromycin. It's essential to highlight the substantial resistance of common pathogens to oral antibiotics. In contrast, the control groups exhibited lower resistance rates across all bacterial isolates.
Conclusion: Antimicrobial resistance is a growing concern among vulnerable IEI patients. We suggest conducting similar investigations in other regions to address this issue. The findings should inform future infection management guidelines for IEIs.