Qom University of Medical Sciences Journal

Background and Objectives: Pseudomonas aeruginosa is one of the most common causes of nosocomial infections. Most laboratories usually use culture method and various biochemical tests for identification of P. aeruginosa, which are time-consuming and sometimes lead to false positive and negative results. The aim of this study was to compare two methods of PCR with DNA extracted by kit and PCR with direct colony for detection of P. aeruginosa isolates.

Methods: In this descriptive-analytical study, out of 395 different clinical isolates, 85 isolates were identified using basic biochemical tests and culture on P. aeruginosa specific media. Then, they were assessed by OPrL, ExoA, algD genes using two methods of direct PCR by using DNA extraction kit and direct PCR and PCR with DNA extracted by kit.

Results: Out of 85 P. aeruginosa isolates detected by phenotypic screening, 81 isolates had OPrL, ExoA, algD genes using PCR with DNA extracted by kit with (amlicon size, 504, 396, and 526 bp) and 80 isolates had the mentioned genes using direct PCR.

Conclusion: This study showed that, acceptable diagnostic results can be achieved in the identification of P. aeruginosa without using extraction kits three stable gens of P. aeruginosa detect by using two different molecular methods. The results showed that, without using extraction kit can be acceptable diagnostic obtained of Pseudomonas aeruginosa. On the other hand, in the obtained results, phenotypic P. aeruginosa detection methods’ error can be observed.