Chronic Airway Infection and Resistance Pattern in Children and Adults with Cystic Fibrosis in Oman: A Single-center Cross-sectional Study.

Objectives: Cystic fibrosis (CF) is a multisystemic genetic disease. Progressive decline in lung function is the major cause of morbidity and mortality in this population, primarily related to chronic airway infection and recurrent pulmonary exacerbations. We sought to assess the pattern of airway bacterial growth among patients with CF in Oman and identify possible risk factors for the hypothesized early Pseudomonas aeruginosa acquisition among this population.

Methods: We conducted a retrospective single-center cross-sectional study that included all patients who attended the CF clinic at Royal Hospital, Oman between 2004 and 2020. Collected data included age, sex, geographic region, date of CF diagnosis, CF genotype, number of siblings with CF, and the date and results of all positive respiratory cultures. Early P. aeruginosa acquisition was defined by a positive respiratory culture for P. aeruginosa before the age of two years. Multi-drug resistant P. aeruginosa was defined as P. aeruginosa not susceptible to ≥ 1 agent in ≥ 3 classes of antimicrobials. The above factors were compared between the early and late P. aeruginosa acquisition groups.

Results: A total of 114 patients were included, and 2393 positive bacterial cultures were analyzed. Eighty-four (73.7%) patients were identified to have a positive culture for P. aeruginosa, including 40 (47.6%) who acquired it before the age of two years. P. aeruginosa remained the most common organism across all age groups. Twenty-six (22.8%) patients were positive for P. aeruginosa on their first respiratory culture, while 56 (49.1%) patients had three or more positive respiratory cultures for P. aeruginosa. Methicillin-resistant Staphylococcus aureus accounted for 7.2% of all positive cultures under the age of one year and peaked at 14.8% between the ages of four and five years. A significant association were found between early P. aeruginosa acquisition and male sex. No significant association was observed between CF genotype, geographic region, age at diagnosis, or the presence of a sibling with CF and early P. aeruginosa acquisition.

Conclusions: Our study demonstrated earlier acquisition of P. aeruginosa and its predominance among children with CF in Oman. Male sex was associated with a higher risk for early P. aeruginosa acquisition. Further prospective studies are needed to confirm this association and identify other possible risk factors. These findings will impact the clinical practice of CF physicians in Oman.