Detection of biofilm formation and assessment of biofilm genes expression in different Pseudomonas aeruginosa clinical isolates

Introduction: Biofilm formation is an important antibiotic resistance mechanism among different bacterial species. Aim: This study aimed to determine the ability of different P. aeruginosa clinical isolates to produce biofilm and its association with las R, lec A and pel A genes expression and antibiotic resistance. Methods: In this study, 100 isolates of P. aeruginosa were obtained from patients with wound infections at Minia University Hospitals. The antibiotic sensitivity of the isolated strains was done using the disc diffusion method. The isolated bacteria were tested for their ability to form biofilm using a microtiter plate assay. The expression of lasR, lecA and pel A genes in isolated strains was detected using real-time rt-PCR. Results: 27 out of 100 P. aeruginosa isolates (27%) were positive biofilm producers: 14% were strong biofilm producers, 7% were moderate biofilm producers and 6% were weak biofilm producers. Resistance to all used antibiotics and multidrug resistance was higher among biofilm producing than non-biofilm producing strains, but the difference was statistically non-significant. The expression of lasR, lecA and pel A genes were detected in 20 (74.1%), 26(96.3%) and 18(66.7%) isolates out of 27 biofilm-producing strains respectively, compared to 23(31.5%), 26(35.6%) and 24(24%) out of 73 non-biofilm producing strains respectively. Conclusion: Biofilm producing strains demonstrated higher expression level of lasR, lecA, and pel A genes with a mean fold change of 357.02 +/- 248.5, 26.7 +/- 23.2 and 420.2 +/- 271.3 respectively, therefore las R, lec A, and pel A genes have a significant role in biofilm formation.