Unveiling the Microbial Landscape: Chronic Airway Colonization in Egyptian Children with Cystic Fibrosis

Background: Cystic fibrosis (CF) is a genetically recessive disease marked by frequent, chronic lung infections that impair lung function and cause early death. Objectives: our aim was to identify the bacteria colonizing the airways among a cohort of Egyptian children with CF and to assess their antimicrobial susceptibility and biofilm formation capacity. Methodology: In this cross-sectional study, we assessed the prevalence of bacterial species colonizing airways of 34 Egyptian pediatric patients with CF. The isolated pathogens underwent antibiotic susceptibility testing using the Kirby–Bauer disc diffusion method and biofilm formation analysis via a microtiter plate assay. Results: In a total of 43 isolated pathogens, the most frequently isolated microorganisms were Staph aureus (S. aureus) (51.2%) followed by Pseudomonas aeruginosa (P. aeruginosa) (34.9%). Other less prevalent bacterial isolates included E. coli, Klebsiella spp., and Acinetobacter spp. (4.7% each). Regarding antibiotic susceptibility profiles, S. aureus demonstrated high resistance to penicillin and cefoxitin (95.5% and 81.8% respectively) followed with erythromycin and tetracycline, with resistance rates of 68.2% and 45.5% respectively. Alarmingly, a high prevalence of Methicillin-Resistant S. aureus (MRSA) was observed among our tested isolates (81.8%). Among P. aeruginosa isolates, cefepime and imipenem exhibited the highest resistance rates (26.7% each), followed by tobramycin (20%). All isolated pathogens produced biofilm with varying degrees. Among them 50% of S. aureus and 66.7% of P. aeruginosa were strong biofilm producers. Conclusion: There was a significantly higher prevalence of S. aureus chronic colonization among our CF patients. Meanwhile chronic colonization with P. aeruginosa was less prevalent. Unfortunately, there was a high prevalence of MRSA and biofilm formation among the isolated bacteria. Implementing strict preventive measures and infection control can help prevent MRSA-related exacerbations in these patients.