Project description:The antibiotic fosfomycin is widely recognized for treatment of lower urinary tract infections caused by Escherichia coli and lately gained importance as a therapeutic option to combat multidrug resistant bacteria. Still, resistance to fosfomycin frequently develops through mutations reducing its uptake. Whereas the inner membrane transport of fosfomycin has been extensively studied in E. coli, its outer membrane (OM) transport remains insufficiently understood. While evaluating minimal inhibitory concentrations in OM porin-deficient mutants, we observed that the E. coli ΔompCΔompF strain is five times more resistant to fosfomycin than the wild type and the respective single mutants. Continuous monitoring of cell lysis of porin-deficient strains in response to fosfomycin additionally indicated the relevance of LamB. Furthermore, the physiological relevance of OmpF, OmpC and LamB for fosfomycin uptake was confirmed by electrophysiological and transcriptional analysis. This study expands the knowledge of how fosfomycin crosses the OM of E. coli.
2024-01-24 | GSE236554 | GEO
Project description:Escherichia coli from bloodstream infections in Oxfordshire
Project description:Efflux pumps of the resistance-nodulation-division (RND) superfamily, particularly the AcrAB-TolC and MexAB-OprM, besides mediating intrinsic and acquired resistance, also intervene in bacterial pathogenicity. Inhibitors of such pumps could restore activities of antibiotics and curb bacterial virulence. Here, we identify pyrrole-based compounds that boost antibiotic activity in Escherichia coli and Pseudomonas aeruginosa by inhibiting their archetype RND transporters. The discovered efflux pump inhibitors (EPIs) inhibit the efflux of fluorescent probes, attenuate persister formation, and diminish resistant mutant development. Molecular docking and biophysical studies revealed that the EPIs bind to AcrB. EPIs also possess an anti-pathogenic potential and attenuate P. aeruginosa virulence in vivo. The excellent efficacy of the EPI-antibiotic combination was evidenced in animal lung infection and sepsis protection models. These findings indicate that EPIs discovered herein with no off-target effects and negligible toxicity are potential antibiotic adjuvants to address life-threatening bacterial infections.
Project description:Evolution of antibiotic resistance in microbes is frequently achieved by acquisition of spontaneous mutations during antimicrobial therapy. Here we demonstrate that inactivation of a central regulator of iron homeostasis (fur) facilitates laboratory evolution of ciprofloxacin resistance in Escherichia coli. To decipher the underlying molecular mechanisms, we first performed a global transcriptome analysis and demonstrated a substantial reorganization of the Fur regulon in response to antibiotic treatment. We hypothesized that the impact of Fur on evolvability under antibiotic pressure is due to the elevated intracellular concentration of free iron and the consequent enhancement of oxidative damage-induced mutagenesis. In agreement with expectations, over-expression of iron storage proteins, inhibition of iron transport, or anaerobic conditions drastically suppressed the evolution of resistance, while inhibition of the SOS response-mediated mutagenesis had no such effect in fur deficient population. In sum, our work revealed the central role of iron metabolism in de novo evolution of antibiotic resistance, a pattern that could influence the development of novel antimicrobial strategies. We used microarrays to identify genotype specific transcriptional changes under severe DNA damaging conditions (antibiotic ciprofloxacin). We treated Escherichia coli cells with a highly toxic level of ciprofloxacin (gyrase inhibitor) for RNA extraction and hybridization on Affymetrix microarrays. We planned to find genotype specific transcriptional responses using WT control (BW25113) and fur-knockout mutant (selected from the KEIO collection) strains during antibiotic treatments. For each treatment type we used two biological replicates.
Project description:Preterm birth is currently the leading cause of neonatal morbidity and mortality. Genetic, immunological and infectious causes are suspected. Preterm infants have a higher risk of severe bacterial neonatal infections, most of which are caused by Escherichia coli an in particular E. coli K1strains. Women with history of preterm delivery have a high risk of recurrence and therefore constitute a target population for the development of vaccine against E. coli neonatal infections. Here, we characterized the immunological, microbiological and protective properties of a live attenuated vaccine candidate in adult female mice and their pups against after a challenge by K1 and non-K1 strains of E. coli. Our results show that the E. coli K1 E11 aroA vaccine induces strong immunity, driven by polyclonal bactericidal antibodies. In our model of meningitis, pups born to mothers immunized before mating were well protected against various K1 and non-K1 strains of E. coli. Given the very high mortality rate and the neurological sequalae associated with neonatal E. coli K1 meningitis, our results constitute preclinical proof of concept for the development of a live attenuated vaccine against severe E. coli infections in women at risk of preterm delivery.
Project description:We report identification and characterization of antibiotic persister mutants carrying characteristic mutations in the Escherichia coli rpoB gene
Project description:Understanding constraints which shape antibiotic resistance is key for predicting and controlling drug resistance. Here, we performed high-throughput laboratory evolution of Escherichia coli. The transcriptome, resistance, and genomic profiles for the evolved strains in 48 environments were quantitatively analyzed. By analyzing the quantitative datasets through interpretable machine learning techniques, the emergence of low dimensional phenotypic states within the 192 strains was observed. Further analysis revealed the underlying biological processes responsible for the distinct states. We also report a novel constraint which leads to decelerated evolution. These findings bridge the genotypic, gene expression, and drug resistance space, and lead to a comprehensive understanding of constraints for antibiotic resistance.
Project description:Persister cells are a sub-population of all bacterial cultures which exhibit a non-inheritable, multi-drug tolerance when subjected to lethal antibiotic challenge. These persisters arise as a result of metabolic dormancy, and can resume growth subsequent to antibiotic challenge, leading to recalcitrance of bacterial infections. Overproduction of DosP, an oxygen sensing protein with phosphodiesterase activity, increases bacterial persistence. Here we performed a microarray to determine the expression profile induced by DosP as a means to elucidate mechanisms of persister cell formation. dosP was overexpressed in Escherichia coli K-12 BW25113 and compared to the empty vector.