Project description:According to our study, Chrysanthemum lavandulifolum extract showed excellent antibiotic effects on Escherichia coli O157:H7. A notable point is that the antibiotic efficacy of the herb extract is on the all three proven targets for main antibiotic drugs that are bacterial cell wall biosynthesis, bacterial protein synthesis and bacterial DNA replication and repair. This multi-target efficacy of the herbal antibiotics may be used as more effective and safe drugs that substitute existing antibiotics.
Project description:Triclosan is a biocidal active agent commonly found in domestic cleaning products, hand sanitizers, cosmetics and personal care products. It is used to control microbial contamination and has a broad-spectrum of activity against many Gram-positive and Gram-negative bacteria. The development of triclosan tolerance with potential cross resistance to clinically relevant antibiotics in zoonotic pathogens is of concern given the widespread use of this active agent in clinical, food processing and domestic environments. Some studies have proposed that an over-dependence on triclosan-containing products could lead to the emergence of clinically important pathogens that are highly tolerant to both biocides and antibiotics. Currently, there is limited understanding of the mechanisms contributing to the emergence of triclosan tolerance in foodborne pathogens at a genetic level. We used microarray analysis to compare gene expression between a wildtype E. coli O157:H19 isolate (WT) with a minimum inhibitory concentration (MIC) to triclosan of 6.25 ug/ml and its laboratory generated triclosan tolerant mutant (M) with a MIC of >8000 ug/ml.
Project description:The intention of this study is to analyse the effect of antibiotics on the gene expression of Escherichia coli. Shaking-flask cultivations of Escherichia coli K12GFP-UTL2 were carried out with a medium containing nalidixic acid. Cultures with antibiotic-free medium, which were run in an identical way, served as reference. Samples were taken at different times during the cultivations, the RNA was isolated and hybridised on whole genome yeast microarrays. Keywords: Influence of toxins on gene expression in E. coli
Project description:To assay every gene in the E. coli genome to identify those that contribute to increased or decreased susceptibility to the antibiotics trimethoprim and sulfamethoxazole. This will help to define more accurately those bacterial cell mechanisms that contribute to these phenomena and provide information that will contribute to the development of new antibiotics, or compounds or known antibiotics that synergise with those already in clinical use. Thus, this set of experiments confirmed that AZT, widely known for its antiviral activity, acts synergistically with trimehoprim.
Project description:Benzalkonium chloride (BC) is a commonly used disinfectant and preservative. This study describes changes in expression level on the transcriptomic and proteomic level for Escherichia coli K12 gradually adapted to a tolerance level towards BC of 7-8 times the initial MIC. Results from DNA arrays and two-dimensional (2-DE) gel electrophoresis for global gene and protein expression studies were confirmed by real time quantitative PCR. Peptide mass fingerprinting by MALDI-TOF MS was used to identify differentially expressed proteins. Changes in expression level in adapted cells were shown for porins, drug transporters, glycolytic enzymes, ribosomal subunits and several genes and proteins involved in protection against oxidative stress and antibiotics. Adapted strains showed increased tolerance to several antibiotics. In conclusion, E. coli K12 adapted to higher tolerance to BC, acquired several general resistance mechanisms including responses normally related to the multiple antibiotic resistance (Mar) regulon and protection against oxidative stress. The results revealed that BC treatment might result in superoxide stress in E. coli. Keywords: Study of resistance mechanism
Project description:Triclosan is a biocidal active agent commonly found in domestic cleaning products, hand sanitizers, cosmetics and personal care products. It is used to control microbial contamination and has a broad-spectrum of activity against many Gram-positive and Gram-negative bacteria. The development of triclosan tolerance with potential cross resistance to clinically relevant antibiotics in zoonotic pathogens is of concern given the widespread use of this active agent in clinical, food processing and domestic environments. Some studies have proposed that an over-dependence on triclosan-containing products could lead to the emergence of clinically important pathogens that are highly tolerant to both biocides and antibiotics. Currently, there is limited understanding of the mechanisms contributing to the emergence of triclosan tolerance in foodborne pathogens at a genetic level. We used microarray analysis to compare gene expression between a wildtype E. coli O157:H19 isolate (WT) with a minimum inhibitory concentration (MIC) to triclosan of 6.25 ug/ml and its laboratory generated triclosan tolerant mutant (M) with a MIC of >8000 ug/ml. Gene expression profiling was performed on untreated E. coli O157:H19 wildtype (WTu) and mutant (Mu), and on the wildtype and mutant treated with 6 ug/ml triclosan for 30 minutes (WTt and Mt respectively). RNA was extracted from three independent biological replicates for WTu, Mu, WTt & Mt for hybridization on Affymetrix GeneChip E. coli Genome 2.0 Arrays. Micorarray analysis including pre-processing, normalisation and statistical analysis were performed using R (R, 2007) version 2.6 and Bioconductor (Gentleman et al. 2004, Genome Biol. 5:R80) version 2.1 as previously described by Morris et al.(2009, Physiol. Genomics 39:28-37).
Project description:Found how E. coli responds to the commonly prescribed antibiotic-inhibitor combination piperacillin and tazobactam, separately and in combination. TraDIS-Xpress was performed following the protocol outlined by Yasir et al 2020 Genome Research. The results suggest tazobactam triggers the activity of multidrug efflux systems that have been previously seen to confer clinical resistance to multiple classes of antibiotics.
Project description:Pathogenic biofilms have been associated with persistent infections due to their high resistance to antimicrobial agents. To identify non-toxic biofilm inhibitors for enterohemorrhagic Escherichia coli O157:H7, indole-3-acetaldehyde was used and reduced E. coli O157:H7 biofilm formation. Global transcriptome analyses revealed that indole-3-acetaldehyde most repressed two curli operons, csgBAC and csgDEFG, and induced tryptophanase (tnaAB) in E. coli O157:H7 biofilm cells. Electron microscopy showed that indole-3-acetaldehyde reduced curli production in E. coli O157:H7. Together, this study shows that Actinomycetales are an important resource of biofilm inhibitors as well as antibiotics.