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Background and Objective: Biofilms caused by pathogenic microorganisms that plays an important role against human health. Due to their resistance to detergents and antimicrobial agent, treatment response of affected patients with these bacteria is difficult. This study was done to evaluate the effect of methanol extract of Nasturtium officinale plant on growth and biofilm formation of Pseudomonas aeruginosa.
Methods: In this descriptive - laboratory study, the extraction was done by Maceration in 80% methanol and by rotary evaporator. The minimum inhibitory concentration (MIC) of Nasturtium officinale extracts were determined by broth microdilution method. Biofilm formation was investigated using the microtiter plate and stained with crystal violet.
Results: The minimum inhibitory concentration of Nasturtium officinale against Pseudomonas aeruginosa was 0.625 mg/ml and the Minimum bactericidal concentration of this extract was 1.25 mg/ml. PAO1 strain and 5 clinical strains were able to biofilm formation. Inhibition of biofilm formation by extract of Nasturtium officinale plant was dependent to concentration. The highest percentage of inhibition of biofilm formation was in the concentration of 7.5 mg/ml and the lowest percentage of inhibition of biofilm formation was in the concentration of 0.11 mg/ml. The mean of Pseudomonas aeruginosa biofilm inhibition by Nasturtium officinale extracts was 72.69±22.27 %. In the concentrations of 7.5, 0.93, 0.46, 0.23 and 0.11 mg/ml, there was a significant difference between clinical strains and PAO1 strain (P<0.05).
Conclusion: Methanolic extracts of Nasturtium officinale plant has anti-bacterial and anti-biofilm effect against Pseudomonas aeruginosa.

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Background and Objective: Various infections and the formation of stones could be the cause for bile duct obstruction of that sterile organ. Determination of pathogenesis factors and the bacteria involved in infections are important in the prevention of disease, and cares needed following surgery. This study was done to determine the bacteria in the gallbladder of patients with cholelithiasis and evaluation of pathogenic factors of the prevalent isolated bacteria.
Methods: In this descriptive laboratory study, 35 samples of gallbladder tissues which contained gallstones were collected under sterile conditions in “Department of General Surgery of Imam Khomeini Hospital”, Tehran, Iran during 2016. The stone types were analyzed and decomposed by chemical procedures, and the bacteria existed in the tissues were also identified using biochemical experiments. The tissues with negative results in microbiological studies were looked for any contaminating bacteria, applying the DNA extracted from gallbladder tissue as a template using F27 and R1492 as the primers for PCR (Polymerase Chain Reaction) amplification of 16SrRNA gene. Those with the positive results of microbiological tests were subjected to the DNA sequencing following gel purification and blasted against the NCBI gene database. The most frequently isolated bacteria were studied according to the intensity of biofilm formation, using the microtitre plate method. CsgF and Ag43 (Flu), the genes involved in the induction of such phenotype were also analyzed in this study. The antibiotic resistance assay of the isolates was performed using disc diffusion procedure.
Results: Thirteen out of thirty five samples of post-surgery gallbladder tissues were found to be infected by different bacteria, including: Klebsiella (3 cases), Escherichia coli (4 cases), Enterobacter (1 case), Staphylococcus aureus (2 cases), Enterococci (2 cases), and Streptococcus (1 case). In 23 out of 35 samples (65.7%), no bacteria could be isolated using microbiological methods. However, in seven out of 23 samples, the amplified 16SrRNA had an indication of Klebsiella (6 cases) and Enterococcus (1 case) isolates. Therefore, the most prevalent genus in gallbladder infections was Klebsiella (47.36%). Chemical analysis showed that the highly frequent compound of gallstones (98%) were of cholesterol and bilirubin. Escherichia coli with fourcases were the highest culture growing isolated bacteria, in all of which, the biofilm formation genes were present. In the two out of four Escherichia coli isolates the intensity of biofilm formation was high. Although, in the remaining two isolates was medium. While, they were found to be sensitive to the most of the antibiotics, they showed resistance to Tetracycline, Ciprofloxacin and Ceftazidime in different ranges.
Conclusion: The present study provided evidence that non-cultural bacteria are hihly present in gallbladder infections. The high potential of the commonly isolated bacteria in biofilm formation should be taken as a warning to follow the precise protocol of antibiotic prescription for treatment of gallbladder infections.

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Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of mortality in immunocompromised patients. One of the most important mechanisms of resistance of this bacterium is biofilm formation. The aim of this study was done to determine the Effect of Morin on Expression of Biofilm Gene of Pseudomonas aeruginosa Isolated from burn wounds by Real time PCR.
Methods: In this descriptive-analytic study 60 sample were collected from burn wounds of patients admitted to the hospitals in Tehran, Iran. Samples were identified by using biochemical methods. The DNA of the isolates was extracted and then antimicrobial activity of morin analyzed by microbroth dilution assay. The presence of biofilm production genes was investigated by PCR. Finally, the expression of lasI gene in combination with Sub-MIC concentration of morin in biofilm-producing bacteria was evaluated using Real time PCR.
Results: From 60 samples that analyzed by Multiplex-PCR, 12 (20%) Pseudomonas aeruginosa strains were isolated in which 12 isolates (100%) were carried lasI and lasR, genes, respectively. 3 isolates (25%) were carried rhlI gene. Sub-MIC concentration of morin in biofilm-producing bacteria reduced lasI gene expression in Pseudomonas aeruginosa.
Conclusion: Morin has significant efficacy on Pseudomonas aeruginosa and could be a good alternative for treatment of antibiotic resistant isolates.