PCR-based assay for the rapid and precise distinction of Pseudomonas aeruginosa from other Pseudomonas species recovered from burns patients

BACKGROUND Pseudomonas aeruginosa is an important lifethreatening nosocomial pathogen which plays a prominent role in wound infections in burns patients. We designed this study to identify the isolates of P. aeruginosa recovered from burns patients at the genus and species levels by means of primers targeting oprI and oprL genes. METHODS During a 5-month period, wound samples were taken from burns patients and plated on MacConkey agar. All suspected colonies were screened for P. aeruginosa by means of a combination of phenotype tests. Specific primers for oprI and oprL genes were then used for the molecular identification of colonies. RESULTS During the 5-month period, bacterial isolates recovered from burn wound infections were analyzed. Phenotype identification tests identified 171 (34.8%) P. aeruginosa isolates. However, molecular techniques that used species-specific primers to detect the amplicon of the oprL gene confirmed the exact identification of P. aeruginosa in only 133 cases; in the other isolates, the use of genus-specific primers detected the amplicon of the oprI gene, which confirmed the identification of fluorescent pseudomonads. CONCLUSIONS This study indicates that molecular detection by means of an assay targeting the oprL gene is a useful technique for the rapid and precise detection of P. aeruginosa in burns patients. In addition to phenotype testing, PCR detection should be carried out in order to promptly ascertain the best aggressive antibiotic therapy for P. aeruginosa infections, thereby significantly improving clinical outcomes.