Antibiotic resistance properties and molecular characterization of Pseudomonas aeruginosa strains from patients with cystic fibrosis (CF) referred to Gholhak Pathobiology Laboratory in Tehran city during 2016-2018

Background and Objectives: Pseudomonas aeruginosa isolates from the lungs of cystic fibrosis (CF) patients are often heterogeneous and antibiotic resistant strains. Our work therefore focused on the antibiotic resistance properties of these P. aeruginosa strains isolated from Iranian patients, as well as the genetic diversity analysis by a repetitive-element-based molecular assay. Methods: This cross-sectional study performed on 100 strains of P. aeruginosa isolated from CF patients. The isolates were diagnosed using standard biochemical tests, and their antibiotic resistance patterns were determined. Molecular diversity investigated by ERIC-PCR and BOX-PCR methods, and the correlation between molecular types and antimicrobial resistance patterns determined by Pearson's chi-square test. Results: The prevalence of multiple drug resistant isolates was 35%, and in terms of hypermutator [HP] phenotypes, only two isolates were HP. Most isolates (96%) were resistant to Rifampin, and the highest susceptibility to Streptomycin, Imipenem, and Meropenem were 96%, 93%, and 94%, respectively. Molecular analysis demonstrated that BOX-PCR fingerprinting produced 24 patterns in eight clusters, while ERIC-PCR resulted in 26 patterns in nine clusters. Conclusion: The detection of large proportions of diversity and multi-antibiotic-resistant P. aeruginosa strains in CF patients within Iran indicates that this pathogen can be a threat to our public health. Our findings are useful for understanding the evolution of P. aeruginosa population in CF patients and identifying new targets for control of CF chronic infections.