Differences of genetic diversity and antibiotics susceptibility of Pseudomonas aeruginosa isolated from hospital, river and coastal seawater.

Pseudomonas aeruginosa is an opportunistic pathogen, and ubiquitously found in natural environments. However, details on difference between clinical and environmental isolates have not been reported enough. In this study, we defined existence of marine specific genogroup and different drug susceptibility among isolates from clinical, river and coastal seawaters. Pseudomonas aeruginosa were isolated by using cetrimide kanamycin nalidixic acid agar media and incubation at 42°C, which was specific selection method of this bacterium from the natural aquatic samples. Pulse field gel electrophoresis analysis showed that the levels of genetic variation within P. aeruginosa were different among environmental sites. Pulse field gel electrophoresis also showed a lower diversity within P. aeruginosa in the coastal waters; and coastal strains isolated different sampling points were positioned closely in the same cluster. Most of the aquatic isolates were sensitive to most of the drugs tested and 'intermediate' to panipenem on the contrast to the clinical isolates, suggesting that the clinical use of antibiotics affect significantly to the emergence of the drug-resistant P. aeruginosa.