Genetic features of clinical Pseudomonas aeruginosa strains.

The genetic features of each isolate were determined by enterobacterial repetitive intergenic consensus (ERIC) primer sequences used in PCR and by searching for six virulence genes (alg D, las B, tox A, plc H, plc N, exo S). 49 (79%) of the isolates were distributed in three ERIC PCR subgroups and showed 62% of similarity. The remaining 13 strains generated unique patterns. The first subgroup was primarily composed of isolates from faeces, these strains indicated over 70% relationship with the next subgroup, and primarily contained strains isolated from wounds and bronchial washings and the last subgroup contained strains isolated from wounds and urine. The unique strains were isolated mainly from urine. Statistical analysis indicated that variations in distribution of virulence genes in P. aeruginosa isolates with respect to strain origin and genomic subgroups were not significant. In the group of 49 strains, 100% gave a positive reaction to alg D, las B and plc H genes, 91.8% to tox A and plc N genes and 83.7% to exo S gene. Among the strains that generated unique (ERIC-PCR) patterns, 69.2% gave a positive reaction to alg D gene, 84.6% to las B gene, 76.9% to tox A, plc N and plc H genes, and 46.15% to exo S gene.