Host specificity of pseudomonas aeruginosa isolates from patients with cystic fibrosis and patients from different clinical backgrounds.

Abstract

Background: Pseudomonas aeruginosa is one of the primary pathogens being isolated more frequently in cystic fibrosis (CF) and exhibits innate resistant to a wide range of antibiotics. Purpose: To determine whether the highly prevalent genotypes of P. aeruginosa are specifically linked to CF patients, isolates from non-CF patients and environment sources were genotypically analyzed. Methods: Collections of P. aeruginosa from lower respiratory secretions (n= 57) were genotyped using pulse-field gel electrophoresis (PFGE). Phenotypic screening for antibiotic susceptibility was performed for the common antimicrobial agents by Etest and automated Phoenix. Results: P. aeruginosa isolates from CF (n=39), 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 the strains fall among 3 major clusters. Cluster A contained 16 isolates from CF patients and 2 environmental; cluster B contained 12 isolates from CF and one environmental while cluster C contained all the isolates from non CF patients and one environmental. The majority of P. aeruginosa strains in CF were resistant to ciprofloxacin (25.7%) followed by amikacin and gentamicin (each 23.6%). Whereas, the majority of isolates from non-CF were resistant to meropenem (69%), which grouped in cluster C. Conclusion: The fingerprints obtained with P. aeruginosa isolates from CF patients have a high degree of similarity, suggesting specific adaptation of these two clones to CF lung. The third non-CF cluster has different clonal origin, indicating specific clustering in both location and patient group.