Aromatic Acid Metabolites of Escherichia coli K-12 Can Induce the marRAB Operon

ABSTRACT MarR is a key regulator of the marRAB operon involved in antibiotic resistance and solvent stress tolerance in Escherichia coli. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate marRAB transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates marRAB transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.

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Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

ISME Communications ◽

10.1038/s43705-021-00041-z ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Yue Xing ◽

Xiaoxi Kang ◽

Siwei Zhang ◽

Yujie Men

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Selective Pressure ◽

Fold Increase ◽

Streptomycin Resistance ◽

Evolutionary Stage ◽

Fitness Costs ◽

Evolutionary Trajectories ◽

K 12 ◽

Late Stages

AbstractTo explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5–6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

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Increased Survival of Antibiotic-Resistant Escherichia coli inside Macrophages

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01632-12 ◽

2012 ◽

Vol 57 (1) ◽

pp. 189-195 ◽

Cited By ~ 33

Author(s):

Migla Miskinyte ◽

Isabel Gordo

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Bacterial Infections ◽

Resistance Mutation ◽

Fitness Cost ◽

Resistance Mutations ◽

Content Type ◽

E Coli ◽

Fitness Effects ◽

K 12

ABSTRACTMutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in therpoB,rpsL, andgyrAgenes, which confer resistance to rifampin, streptomycin, and nalidixic acid, respectively. These antibiotics are frequently used in the treatment of bacterial infections. We measured two important fitness traits—growth rate and survival ability—of 12Escherichia coliK-12 strains, each carrying a single resistance mutation, in the presence of macrophages. Strikingly, we found that 67% of the mutants survived better than the susceptible bacteria in the intracellular niche of the phagocytic cells. In particular, allE. colistreptomycin-resistant mutants exhibited an intracellular advantage. On the other hand, 42% of the mutants incurred a high fitness cost when the bacteria were allowed to divide outside of macrophages. This study shows that single nonsynonymous changes affecting fundamental processes in the cell can contribute to prolonged survival ofE. coliin the context of an infection.

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Core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00341-21 ◽

2021 ◽

Author(s):

Jianli Wang ◽

Wenjian Ma ◽

Yu Fang ◽

Hao Liang ◽

Huiting Yang ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Cell Envelope ◽

Gene Clusters ◽

Gram Negative Bacteria ◽

Multiple Antibiotic Resistance ◽

Core Oligosaccharide ◽

Gram Negative ◽

The Core ◽

K 12

Gram-negative bacteria are intrinsically resistant to antibiotics due to the presence of the cell envelope, but mechanisms are still not fully understood. In this study, a series of mutants that lack one or more major components associated with the cell envelope were constructed from Escherichia coli K-12 W3110. WJW02 can only synthesize Kdo 2 -lipid A which lacks the core oligosaccharide portion of lipopolysaccharide. WJW04, WJW07 and WJW08 were constructed from WJW02 by deleting the gene clusters relevant to the biosynthesis of exopolysaccharide, flagella and fimbria, respectively. WJW09, WJW010 and WJW011 cells cannot synthesize exopolysaccharide, flagella and fimbria, respectively. Comparing to the wild type W3110, mutants WJW02, WJW04, WJW07 and WJW08 cells showed decreased resistance to more than 10 different antibacterial drugs, but not the mutants WJW09, WJW010 and WJW011. This indicates that the core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in E. coli and the 1 st heptose in core oligosaccharide portion is critical. Furthermore, the removal of the core oligosaccharide of LPS leads to influences on cell wall morphology, cell phenotypes, porins, efflux systems, and the respond behaviors to antibiotic stimulation. The results demonstrated the important role of lipopolysaccharide on the antibiotic resistance of Gram-negative bacteria.

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The Conjugation Window in an Escherichia coli K-12 Strain with an IncFII Plasmid

Applied and Environmental Microbiology ◽

10.1128/aem.00948-20 ◽

2020 ◽

Vol 86 (17) ◽

Cited By ~ 1

Author(s):

Brendan Headd ◽

Scott A. Bradford

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Antibiotic Resistance Genes ◽

Time Frame ◽

Environmental Aspect ◽

Content Type ◽

E Coli ◽

Donor Cells ◽

K 12 ◽

Regulatory Controls

ABSTRACT Many studies have examined the role that conjugation plays in disseminating antibiotic resistance genes in bacteria. However, relatively little research has quantitively examined and modeled the dynamics of conjugation under growing and nongrowing conditions beyond a couple of hours. We therefore examined growing and nongrowing cultures of Escherichia coli over a 24-h period to understand the dynamics of bacterial conjugation in the presence and absence of antibiotics with pUUH239.2, an IncFII plasmid containing multiantibiotic- and metal-resistant genes. Our data indicate that conjugation occurs after E. coli cells divide and before they have transitioned to a nongrowing phase. The result is that there is only a small window of opportunity for E. coli to conjugate with pUUH239.2 under both growing and nongrowing conditions. Only a very small percentage of the donor cells likely are capable of even undergoing conjugation, and not all transconjugants can become donor cells due to molecular regulatory controls and not being in the correct growth phase. Once a growing culture enters stationary phase, the number of capable donor cells decreases rapidly and conjugation slows to produce a plateau. Published models did not provide accurate descriptions of conjugation under nongrowing conditions. We present here a modified modeling approach that accurately describes observed conjugation behavior under growing and nongrowing conditions. IMPORTANCE There has been growing interest in horizontal gene transfer of antibiotic resistance plasmids as the antibiotic resistance crisis has worsened over the years. Most studies examining conjugation of bacterial plasmids focus on growing cultures of bacteria for short periods, but in the environment, most bacteria grow episodically and at much lower rates than in the laboratory. We examined conjugation of an IncFII antibiotic resistance plasmid in E. coli under growing and nongrowing conditions to understand the dynamics of conjugation under which the plasmid is transferred. We found that conjugation occurs in a narrow time frame when E. coli is transitioning from a growing to nongrowing phase and that the conjugation plateau develops because of a lack of capable donor cells in growing cultures. From an environmental aspect, our results suggest that episodic growth in nutrient-depleted environments could result in more conjugation than sustained growth in a nutrient rich environment.

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Integron-Mediated Antibiotic Resistance in Shiga Toxin–Producing Escherichia coli

Journal of Food Protection ◽

10.4315/0362-028x-72.1.21 ◽

2009 ◽

Vol 72 (1) ◽

pp. 21-27 ◽

Cited By ~ 12

Author(s):

SUPAKANA NAGACHINTA ◽

JINRU CHEN

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Resistance Genes ◽

Shiga Toxin ◽

Antibiotic Resistance Genes ◽

Conjugative Plasmid ◽

E Coli ◽

Class 1 Integrons ◽

Class 1 ◽

K 12

This study was undertaken to characterize the integrons present in a group of Shiga toxin–producing Escherichia coli (STEC) isolates and the ability of these integrons to transfer antibiotic resistance genes from STEC to E. coli K-12 MG1655. A total of 177 STEC isolates were analyzed for antibiotic susceptibility and the presence of integrons. Class 1 integrons were detected in 14 STEC isolates, and a class 2 integron was identified in 1 STEC isolate. The STEC isolates positive for class 1 integrons were resistant to streptomycin (MICs > 128 μg/ml) and sulfisoxazole (MICs > 1,024 μg/ml), and the isolate positive for the class 2 integron was resistant to streptomycin (MIC of 128 μg/ml), trimethoprim (MIC > 256 μg/ml), and streptothricin (MIC > 32 μg/ml). Results of restriction digestion and nucleotide sequencing revealed that the cassette regions of the class 1 integrons had a uniform size of 1.1 kb and contained a nucleotide sequence identical to that of aadA1. The class 2 integron cassette region was 2.0 kb and carried nucleotide sequences homologous to those of aadA1, sat1, and dfrA1. Results of the conjugation experiments revealed that horizontal transfers of conjugative plasmids are responsible for the dissemination of class 1 integron–mediated antibiotic resistance genes from STEC to E. coli K-12 MG1655. Antibiotic resistance traits not mediated by integrons, such as resistance to tetracycline and oxytetracycline, were cotransferred with the integron-mediated antibiotic resistance genes. The study suggested a possible role of integron and conjugative plasmid in dissemination of genes conferring resistance to antibiotics from pathogenic to generic E. coli cells.

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Role of Lipopolysaccharides in Antibiotic Resistance and Bacteriophage Adsorption of Escherichia coli K-12

Journal of Bacteriology ◽

10.1128/jb.105.3.968-975.1971 ◽

1971 ◽

Vol 105 (3) ◽

pp. 968-975 ◽

Cited By ~ 122

Author(s):

Shigeo Tamaki ◽

Tomoyasu Sato ◽

Michio Matsuhashi

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

K 12

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The Periplasmic Murein Peptide-Binding Protein MppA Is a Negative Regulator of Multiple Antibiotic Resistance in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.181.16.4842-4847.1999 ◽

1999 ◽

Vol 181 (16) ◽

pp. 4842-4847 ◽

Cited By ~ 16

Author(s):

HongShan Li ◽

James T. Park

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Binding Protein ◽

Wide Spectrum ◽

Negative Regulator ◽

Null Mutant ◽

Multiple Antibiotic Resistance ◽

Resistance Phenotype ◽

E Coli ◽

K 12

ABSTRACT MppA is a periplasmic binding protein in Escherichia coli essential for uptake of the cell wall murein tripeptidel-alanyl-γ-d-glutamyl-meso-diaminopimelate. We have found serendipitously that E. coli K-12 strains carrying a null mutation in mppA exhibit increased resistance to a wide spectrum of antibiotics and to cyclohexane. Normal sensitivity of the mppA mutant to these agents is restored by mppA expressed from a plasmid. As is observed in the multiple antibiotic resistance phenotype in E. coli cells, the mppA null mutant overproduces the transcriptional activator, MarA, resulting in expression of the membrane-bound AcrAB proteins that function as a drug efflux pump. Reduced production of OmpF similar to that observed in the multiple antibiotic resistance phenotype is also seen in the mppA mutant. These and other data reported herein indicate that MppA functions upstream of MarA in a signal transduction pathway to negatively regulate the expression ofmarA and hence of the MarA-driven multiple antibiotic resistance. Overproduction of cytoplasmic GadA and GadB and of several unidentified cytoplasmic membrane proteins as well as reduction in the amount of the outer membrane protein, OmpP, in the mppAnull mutant indicate that MppA regulates a number of genes in addition to those already known to be controlled by MarA.

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Specific phenotypic, genomic, and fitness evolutionary trajectories toward antibiotic resistance induced by pesticide co-stressors in Escherichia coli

10.1101/2021.07.13.452255 ◽

2021 ◽

Author(s):

Yue Xing ◽

Xiaoxi Kang ◽

Siwei Zhang ◽

Yujie Men

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Selective Pressure ◽

Fold Increase ◽

Evolutionary Stage ◽

Fitness Costs ◽

Evolutionary Trajectories ◽

Resistant Mutants ◽

K 12 ◽

Late Stages

To explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolution trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5 ~ 6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

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Benzoate- and Salicylate-Tolerant Strains of Escherichia coli K-12 Lose Antibiotic Resistance during Laboratory Evolution

Applied and Environmental Microbiology ◽

10.1128/aem.02736-16 ◽

2016 ◽

Vol 83 (2) ◽

Cited By ~ 16

Author(s):

Kaitlin E. Creamer ◽

Frederick S. Ditmars ◽

Preston J. Basting ◽

Karina S. Kunka ◽

Issam N. Hamdallah ◽

...

Keyword(s):

Escherichia Coli ◽

Drug Resistance ◽

Antibiotic Resistance ◽

Multidrug Resistance ◽

Gut Microbiome ◽

Nucleotide Polymorphisms ◽

Content Type ◽

Large Deletions ◽

Increased Sensitivity ◽

K 12

ABSTRACT Escherichia coli K-12 W3110 grows in the presence of membrane-permeant organic acids that can depress cytoplasmic pH and accumulate in the cytoplasm. We conducted experimental evolution by daily diluting cultures in increasing concentrations of benzoic acid (up to 20 mM) buffered at external pH 6.5, a pH at which permeant acids concentrate in the cytoplasm. By 2,000 generations, clones isolated from evolving populations showed increasing tolerance to benzoate but were sensitive to chloramphenicol and tetracycline. Sixteen clones grew to stationary phase in 20 mM benzoate, whereas the ancestral strain W3110 peaked and declined. Similar growth occurred in 10 mM salicylate. Benzoate-evolved strains grew like W3110 in the absence of benzoate, in media buffered at pH 4.8, pH 7.0, or pH 9.0, or in 20 mM acetate or sorbate at pH 6.5. Genomes of 16 strains revealed over 100 mutations, including single-nucleotide polymorphisms (SNPs), large deletions, and insertion knockouts. Most strains acquired deletions in the benzoate-induced multiple antibiotic resistance (Mar) regulon or in associated regulators such as rob and cpxA, as well as the multidrug resistance (MDR) efflux pumps emrA, emrY, and mdtA. Strains also lost or downregulated the Gad acid fitness regulon. In 5 mM benzoate or in 2 mM salicylate (2-hydroxybenzoate), most strains showed increased sensitivity to the antibiotics chloramphenicol and tetracycline; some strains were more sensitive than a marA knockout strain. Thus, our benzoate-evolved strains may reveal additional unknown drug resistance components. Benzoate or salicylate selection pressure may cause general loss of MDR genes and regulators. IMPORTANCE Benzoate is a common food preservative, and salicylate is the primary active metabolite of aspirin. In the gut microbiome, genetic adaptation to salicylate may involve loss or downregulation of inducible multidrug resistance systems. This discovery implies that aspirin therapy may modulate the human gut microbiome to favor salicylate tolerance at the expense of drug resistance. Similar aspirin-associated loss of drug resistance might occur in bacterial pathogens found in arterial plaques.

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