title: Genetic relatedness and host specificity of Pseudomonas aeruginosa isolates from cystic fibrosis and non-cystic fibrosis patients.
abstract: BACKGROUND
  Pseudomonas aeruginosa is one of the primary pathogens isolated more frequently in cystic fibrosis (CF) and it exhibits innate resistance to a wide range of antibiotics.
  
  
  OBJECTIVE
  We sought to determine whether the highly prevalent genotypes of P. aeruginosa are specifically linked to CF patients and have any related multidrug antibiotic resistance. Isolates from hospitalized non-CF patients and from environmental sources were also genotypically analyzed.
  
  
  METHODS
  Collections of P. aeruginosa from lower respiratory secretions (n=45) were genotyped using pulsed-field gel electrophoresis (PFGE). Phenotypic screening for antibiotic susceptibility was performed for the common antimicrobial agents by E-test and automated Phoenix method.
  
  
  RESULTS
  P. aeruginosa isolates from CF (n=32), hospitalized non-CF patients (n=13), and environment sources (n=5) were analyzed. The population structure of P. aeruginosa is highly diverse and population-specific. All PFGE results of P. aeruginosa isolates fall among four major clusters. Cluster 1 contained 16 P. aeruginosa isolates from CF patients and two from environmental sources; cluster 2 contained 11 P. aeruginosa isolates from CF and one each from non-CF and environmental sources; cluster 3 contained 12 P. aeruginosa isolates from hospitalized non-CF patients and two P. aeruginosa isolates from one CF patient and one environmental source; and cluster 4 consisted of three isolates from CF patients and one from the environment. The majority of multidrug-resistant P. aeruginosa isolates were in clusters 3 and 4. P. aeruginosa isolates from CF patients were resistant to ciprofloxacin (34.4%) followed by resistance to amikacin and gentamicin (each 28%), whereas the majority of isolates from non-CF patients were resistant to meropenem (69%) and were grouped in cluster 3.
  
  
  CONCLUSIONS
  PFGE of P. aeruginosa isolates from CF patients shows a high degree of similarity, suggesting specific adaptation of these clones to CF-affected lungs. The hospitalized non-CF cluster has a different clonal origin, indicating specific clustering in a specific location, suggesting hospital-acquired P. aeruginosa infections.
authors.affiliation: Department of Pediatrics, Hamad Medical Corporation, Qatar University, Doha, Qatar.
authors.forename: Atqah
authors.initials: A
authors.lastname: AbdulWahab
authors.affiliation: Microbiology Division, Department of Laboratory Medicine and Pathology, Hamad Medical Corporation, Qatar University, Doha, Qatar.
authors.forename: Saad J
authors.initials: SJ
authors.lastname: Taj-Aldeen
authors.affiliation: Microbiology Division, Department of Laboratory Medicine and Pathology, Hamad Medical Corporation, Qatar University, Doha, Qatar.
authors.forename: Emad
authors.initials: E
authors.lastname: Ibrahim
authors.affiliation: Molecular Biology Unit, Central Food Laboratories, Supreme Council of Health, Qatar University, Doha, Qatar.
authors.forename: Shaikha H
authors.initials: SH
authors.lastname: Abdulla
authors.affiliation: Molecular Biology Unit, Central Food Laboratories, Supreme Council of Health, Qatar University, Doha, Qatar.
authors.forename: Ramees
authors.initials: R
authors.lastname: Muhammed
authors.affiliation: Molecular Biology Unit, Central Food Laboratories, Supreme Council of Health, Qatar University, Doha, Qatar.
authors.forename: Irshad
authors.initials: I
authors.lastname: Ahmed
authors.affiliation: Department of Health Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar.
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Abdeen
authors.affiliation: Department of Health Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar.
authors.forename: Omnia
authors.initials: O
authors.lastname: Sadek
authors.affiliation: Department of Health Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar.
authors.forename: Marawan
authors.initials: M
authors.lastname: Abu-Madi
keywords: Pseudomonas aeruginosa; cystic fibrosis; drug susceptibility testing; pulsed-field gel electrophoresis