Background: Colon cancer is one of the most common malignancies and the fourth leading cause of cancerrelated mortality in the world. Colibactin, which is synthesized by the pks genomic island of E. coli interfere with the eukaryotic cell cycle. Cinnamon has an antimicrobial effect and considered as a colon cancer-preventing agent. The aim of the study was to evaluate the effects of cinnamon extract and cinnamaldehyde on clbB gene expression and biofilm formation in clinical isolates of E. coli. Methods: Thirty E. coli carrying pks gene were isolated from the colon cancer patients, inflammatory bowel disease and healthy subjects. Antibiotic susceptibility was evaluated by disk diffusion method and the minimum inhibitory concentration of cinnamon essential oil and cinnamaldehyde by microdilution broth method. In vitro biofilm formation of E.coli isolates was monitored using a microtiter plate method. The presence of clbB, clbA and clbQ genes in E.coli isolates were evaluated by PCR. The effect of cinnamaldehyde and cinnamon essential oil on clbB gene expression was evaluated by Real-Time PCR. Results: The highest antibiotic resistance was obtained with 94.4% for ticarcillin-clavulanic acid, azithromycin, amoxicillin, and amikacin. The MIC for all clinical isolates was 32 μl/ml of cinnamon essential oil and the MIC of cinnamaldehyde was between 0.00002 to 0.03 μl/ml. After exposure of isolates to cinnamon extract and cinnamaldehyde, 40 and 13.3% were weakly biofilm producers, respectively. The frequencies of clbB, clbA, and clbQ genes were 23.3, 23.3, and 26.7%, respectively. The expression of clbB gene in the presence of the Sub-MIC concentration of cinnamon essential oil and cinnamaldehyde was decreased in 8 isolates compared to untreated isolates (p-value < 0.05). Conclusions: The antibacterial activity of cinnamaldehyde and cinnamon essential oil allows the use of these herbal compounds for treatment or supplements in infections caused by E. coli and in patients with suspected colorectal cancer.
Background:To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. Objectives: The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for each) were examined for chlorhexidine digluconate effects on biofilm formation and planktonic growth using microtiter plates. In all of the examined strains in the presence of chlorhexidine digluconate, biofilm development and planktonic growth were affected at the same concentrations of the disinfectant. Results: Chlorhexidine digluconate inhibited the planktonic growth of different bacterial species at sub-MICs. But they were able to induce biofilm development of the E. coli, Salmonella spp., S. aureus and Str. agalactiae strains. Conclusions: Bacterial resistance against chlorhexidine is increasing. Sub-MIC doses of chlorhexidine digluconate can stimulate the formation of biofilm strains.
Methicillin-Resistant
Staphylococcus aureus
(MRSA) biofilms are involved in various nosocomial infections, being in the limelight of academic research. The current study aimed to determine the antimicrobial effects of melittin on planktonic and biofilm forms of
S. aureus
. Following the identification of MRSA and SCCmec types (using PCR method), Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and fractional inhibitory concentration index (FICi), for melittin and mupirocin were determined by broth microdilution assay. Melittin anti-biofilm activity was determined, using a microtiter-plate test (MtP) and scanning electron microscope (SEM) methods. The quorum sensing inhibitory activity of ½ MIC melittin was examined using a quantitative real-time RT-PCR method, and melittin cytotoxicity on Vero cells was examined by tetrazolium-based colorimetric (MTT) test. The Results of our study showed that Geometric means of MIC values of the melittin and mupirocin were 4.4 and 14.22 μg/ml respectively. The geometric mean of the FICi for both melittin-mupirocin was 0.75. No
S. aureus
biofilm was formed and
hld
gene (as a biofilm regulator) expression down-regulated. It seems that melittin can be useful in the treatment of
S. aureus
infections (especially MRSA) by reducing the
hld
expression. Furthermore, synergistic growth-inhibitory effects of mupirocin with melittin could be considered as a promising approach in the treatment of MRSA isolates.
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