Effectiveness of imipenem stress on upregulation of phzM expression encoding pyocyanin production by Pseudomonas aeruginosa clinical isolates

Hitherto, studies on the expression of phzM gene that has a role in pyocyanin pigment production by Pseudomonas aeruginosa isolates under imipenem stress had not been determined. Hence, the assessment of imipenem stress on the expression of phzM gene is the main focus of contemporaneous study. Thirty Pseudomonas aeruginosa isolates were obtained from Department of Biology, College of Science, University of Baghdad. Isolates were previously diagnosed as Pseudomonas aeruginosa by Vitek-2 system. Investigation of biofilm formation capability was achieved by conducting microtiter plate method. Furthermore, phzM was ascertained in Pseudomonas aeruginosa isolates using conventional PCR technique. while, qRT-PCR technique was undertaken to check the expression of phzM in presence and absence of imipenem. Results revealed that out of 30 isolates, 7(23.33%) formed strong biofilm, thirteen (43.33%) generated moderate biofilm and ten (33.33%) produced weak biofilm. The remaining of the present experiment was done upon choosing strong biofilm former only. Phenotypically, the including of imipenem resulted in significant reduction (P<0.05) of biofilm formation, meanwhile, genotypic results indicated that imipenem stress upregulated the phzM gene expression.