Isolation, Identification and Antibiotic Resistance of Anaerobic Bacteria in Sputum of Cystic Fibrosis Patients from Children s Medical Center of Tehran, Iran

Background and Aim: Following genetic defects in cystic fibrosis (CF), mucus accumulation and hypoxic gradients develop in the lungs creating conditions for the anaerobic bacterial colonization. This study investigated the difference between the prevalence of some anaerobic bacteria and antibiotic resistance among healthy and CF groups. Materials and Methods: In this research, anaerobic bacteria were investigated in sputum samples of the CF patients (50 people) and the healthy individuals (18 people) in Tehran, Iran by culture method during 2021-2022. The sputum samples were cultured on Brucella blood agar, Brain heart infusion agar with vancomycin, Laked brucella blood agar with kanamycin and vancomycin, and Brucella blood agar with neomycin and vancomycin. Gram-negative and Gram-positive isolates were identified using biochemical methods and 16S rRNA sequencing, respectively. In addition, the minimum inhibitory concentration (MIC) of the bacterial isolates was tested for ampicillin, clindamycin and ampicillin/sulbactam using E-test strips. Results: In the culture-based method, anaerobic bacteria were isolated in 33% and 24% of the healthy and CF groups, respectively. Bacterial isolates detected include Dialister spp., Fusobacterium spp., Lactobacillus spp., and Prevotella spp. The Fusobacterium isolates from the healthy group were sensitive to ampicillin, but 33% of Fusobacterium isolates from the CF group showed resistance to this antibiotic. Conclusion: In this study, the presence of anaerobic bacteria in the lungs of healthy and CF individuals was determined. The total frequency of these bacteria was higher in the healthy group than the CF group. The abundance of Gram-positive Lactobacillus bacteria, as potentially beneficial bacteria, was lower in the CF patients than in the healthy individuals.