Background: Different respiratory sampling methods exist to identify lower airway pathogens in patients with cystic fibrosis (CF). Bronchoalveolar lavage (BAL) is considered the "gold standard.". Because BAL is invasive and cannot be repeated frequently, identification of lower respiratory tract pathogens in CF patients is challenging. Other sampling techniques are sputum, cough, and nasal swabs.
The aim of the work: To differentiate between the microbiological results of bronchoalveolar lavage (BAL), sputum and cough swabs in CF children and to evaluate their accuracy in detecting lower respiratory tract organisms.
Patients and Methods: Microbiological results detected by these different sampling methods were compared in all enrolled CF patients (n=31). Specificity, sensitivity, positive (PPV), and negative (NPV) predictive values were calculated.
Results: Regarding microbiological results, Concordance was found between BAL and sputum as regards Pseudomonas spp., Klebsiella spp. and Enterobacter spp., except for Staph aureus (P 0.039). overall low sensitivity (7.1%) and low accuracy (16.1%) of cough swabs to detect lower airway pathogens [Pseudomonas spp., Staphylococcus aureus spp., Klebsiella spp. and Enterobacter spp.] in children with CF followed by sputum analysis as it showed sensitivity (85.7%) and accuracy (80.6%) while BAL showed highest sensitivity (86.2%) and highest accuracy (82.9%).
Conclusion: Our findings suggested that sputum samples showed a good bacteriologic concordance with BAL in detecting lower airway pathogens, While Cough swabs showed the lowest accuracy in detecting the presence of CF pathogens in clinically stable CF children. However, BAL should be performed in symptomatic patients who could not expectorate and had a negative cough swab and sputum sample.