Study of virulence genes and related with biofilm formation in Pseudomonas aeruginosa isolated from clinical samples of Iranian patients; A systematic review

Electrochemical Control of Biofilm Formation and Approaches to Biofilm Removal

This review deals with microbial adhesion to metal-based surfaces and the subsequent biofilm formation, showing that both processes are a serious problem in the food industry, where pathogenic microorganisms released from the biofilm structure may pollute food and related material during their production. Biofilm exhibits an increased resistance toward sanitizers and disinfectants, which complicates the removal or inactivation of microorganisms in these products. In the existing traditional techniques and modern approaches for clean-in-place, electrochemical biofilm control offers promising technology, where surface properties or the reactions taking place on the surface are controlled to delay or prevent cell attachment or to remove microbial cells from the surface. In this overview, biofilm characterization, the classification of bacteria-forming biofilms, the influence of environmental conditions for bacterial attachment to material surfaces, and the evaluation of the role of biofilm morphology are described in detail. Health aspects, biofilm control methods in the food industry, and conventional approaches to biofilm removal are included as well, in order to consider the possibilities and limitations of various electrochemical approaches to biofilm control with respect to potential applications in the food industry.

Isolation and identification of Streptomyces tunisiensis from Garmsar salt cave soil with antibacterial and gene expression activity against Pseudomonas aeruginosa

It is known that more than 70% of the current antibiotics have been produced by Streptomyces; therefore, the main goal of the present study was to isolate halophiles Streptomyces to investigate their antimicrobial properties on the expression of the pathogenic genes of clinically resistant Pseudomonas aeruginosa. To this aim, isolation of Streptomyces from soil was performed by serial dilution method, and cultivation on ISP2 and SCA medium. The secondary metabolite was extracted by ethyl acetate method. The presence of exo A, alg D and oprl genes were determined by PCR in 50 clinical isolates of Pseudomonas aeruginosa. The inhibitory effect of active metabolites on gene expression were investigated by employing the real-time PCR technique. The purification of secondary metabolites were performed by employing the HPLC technique. Moreover, the FTIR technique was employed to determine the functional groups to help performing identifications by employing the LC-MS technique. Finally, selected Streptomyces was identified by 16S ribosomal RNA gene. Accordingly, the possible forms of Streptomyces were isolated and identified, in which Streptomyces number 25 had the highest growth inhibition zone against the clinical strains of Pseudomonas aeruginosa. The obtained results of molecular analysis showed 95.4% similarity to Streptomyces tunisiensis. The effect of selected Streptomyces secondary metabolites reduced expressions of both of exo A and algD genes in 1024μg/mL concentration. In this regard, the potent fraction could be known as an isobutyl Nonactin analogue. The concluding remarks of this work showed the antimicrobial activity of halophilus Streptomyces species against the resistant strains of Pseudomonas aeruginosa with the ability of producing antibiotics proposing for running further investigations to determine the active compound structures.