Molecular analysis of Pseudomonas aeruginosa strains isolated from cystic fibrosis patients.

Pseudomonas aeruginosa is a severe bacterial pathogen. Due to the genetic flexibility among strains, chronic airways infection can lead to mortality among cystic fibrosis (CF) patients. It is essential to develop patient-specific therapy which will rely on phenotypic and genomic diversity. The primary objective of this study was to assess the genomic variability of P. aeruginosa strains, using two different molecular techniques for tracking the epidemiological transmissions. This study applied a multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) for an efficient genotyping of clinical P. aeruginosa strains isolated from CF patients and compared results with a TRS-PCR typing. The percentage similarity analysis was performed using the categorical multi-state coefficient and UPGMA method. Based on the MLVA and TRS-PCR group assessment, 43 P. aeruginosa strains/variants were detected among the 63 clinical isolates from eight CF patients. The study of P. aeruginosa isolates has revealed that during chronic bacterial infections, CF patients harbor different P. aeruginosa strains or variants within the same host over the years. P. aeruginosa genotypes diversity may result from infection with several strains and result from a microevolution process of an initially acquired strain. The TRS-PCR method proposed in this work can complement the MLVA scheme. It can also be used as a preliminary method for genetic typing of P. aeruginosa isolates in CF patients.