Reviving Antibiotics: Efflux Pump Inhibitors That Interact with AcrA, a Membrane Fusion Protein of the AcrAB-TolC Multidrug Efflux Pump

Abdali, Narges; Parks, Jerry M.; Haynes, Keith M.; Chaney, Julie L.; Green, Adam T.; Wolloscheck, David; Walker, John K.; Rybenkov, Valentin V.; Baudry, Jérôme; Smith, Jeremy C.; Zgurskaya, Helen I.

doi:10.1021/acsinfecdis.6b00167

Cited by 99 publications

(140 citation statements)

References 40 publications

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“…The AcrAB-TolC pump that belongs to the RND family is the main efflux pump in E. coli clinical isolates (10). This pump is composed of an inner membrane transporter AcrB, periplasmic membrane fusion protein AcrA, and an outer membrane channel TolC (11).…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial Resistance, Biofilm Formation, and Phylogenetic Grouping of Uropathogenic Escherichia coli Isolates in Egypt: The Role of Efflux Pump-Mediated Resistance

Gawad¹,

Helmy²,

Tawakkol³

et al. 2018

Jundishapur J Microbiol

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Background: Urinary tract infections are the most commonly encountered infections in clinics and outpatient settings and are mainly caused by Uropathogenic Escherichia coli (UPEC). Multidrug-resistant bacteria (MDR) have become a major public health threat, worldwide. Objectives: This study aimed to investigate the prevalence of the MDR phenotype, efflux pump-mediated resistance, and the ability for in vitro biofilm formation among UPEC clinical isolates from Egypt. Methods: Uropathogenic E. coli isolates were collected from two Egyptian governorates, identified, and classified to their corresponding phylogenetic group by the polymerase chain reaction (PCR). Antimicrobial susceptibility testing was done using the Kirby-Bauer disk diffusion method. AcrAB-TolC efflux pump major genes were detected by PCR; efflux pump-mediated resistance was determined by the efflux pump inhibitor microplate-based assay. The ability for in-vitro biofilm formation was also tested. Results:The phylogenetic analysis of the UPEC isolates revealed that most of the isolates belonged to groups B2 and D. The MDR phenotype was detected in 90.8% of UPEC isolates; efflux pump-mediated resistance was detected in all MDR isolates. The acrA, acrB, and tolC were detected in 74.84% of MDR isolates. The ability for in-vitro biofilm formation was recorded in 76.5% of the UPEC isolates. Conclusions:The MDR phenotype and the ability for in-vitro biofilm formation were predominant among UPEC in Egypt. The high prevalence of MDR efflux pumps necessitates the application of new treatment strategies to inhibit this phenomenon.

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Section: Introductionmentioning

confidence: 99%

Antimicrobial Resistance, Biofilm Formation, and Phylogenetic Grouping of Uropathogenic Escherichia coli Isolates in Egypt: The Role of Efflux Pump-Mediated Resistance

Gawad¹,

Helmy²,

Tawakkol³

et al. 2018

Jundishapur J Microbiol

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“…Compounds having an MIC ≤100 μM in combination with novobiocin were then evaluated in a checkerboard assay to determine the minimum potentiation concentration (MPC) that results in a fourfold improvement (MPC 4 ) in the MIC of novobiocin. 20 Compounds with an MPC 4 Nov ≤ 50 μM were examined for their affinity as substrates for the AcrAB-TolC efflux pump and also their ability to permeate the OM barrier. To accomplish this, compounds were tested in two additional cell-based bacterial growth inhibition assays.…”

Section: Resultsmentioning

confidence: 99%

“…20,22 The SPR assay was validated using both negative and positive controls, as described previously. 20 The HT uptake assay was performed in a temperature-controlled micro-plate reader (Tecan Spark 10M) equipped with a sample injector, in fluorescence mode. Data were fitted to extract initial rates, as described previously.…”

Section: Methodsmentioning

confidence: 99%

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Identification and Structure–Activity Relationships of Novel Compounds that Potentiate the Activities of Antibiotics in Escherichia coli

et al. 2017

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In Gram-negative bacteria, efflux pumps are able to prevent effective cellular concentrations from being achieved for a number of antibiotics. Small molecule adjuvants that act as efflux pump inhibitors (EPIs) have the potential to reinvigorate existing antibiotics that are currently ineffective due to efflux mechanisms. Through a combination of rigorous experimental screening and in silico virtual screening we recently identified novel classes of EPIs that interact with the membrane fusion protein AcrA, a critical component of the AcrAB-TolC efflux pump in E. coli. Herein, we present initial optimization efforts and structure-activity relationships around one of those previously described hits, NSC 60339 (1). From these efforts we identified two compounds, SLUPP-225 (17h) and SLUPP-417 (17o), which demonstrate favorable properties as potential EPIs in E. coli cells including the ability to penetrate the outer membrane, improved inhibition of efflux relative to 1 and potentiation of the activity of novobiocin and erythromycin.

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“…Initially, macrolides were believed to block the passage of all peptides through the PET when they are 2–5 amino acids long. However, recent studies have shown that several proteins with specific N‐terminal sequences can still be synthesized even when a macrolide is bound to the ribosome and that protein synthesis can become interrupted at any stage in response to specific stalling motifs . The role of this selective protein inhibition in macrolide activity is presently unclear.…”

Section: Introductionmentioning

confidence: 99%

Toward the rational design of macrolide antibiotics to combat resistance

et al. 2017

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Macrolides, one of the most prescribed classes of antibiotics, bind in the bacterial ribosome's polypeptide exit tunnel and inhibit translation. However, mutations and other ribosomal modifications, especially to the base A2058 of the 23S rRNA, have led to a growing resistance problem. Here, we have used molecular dynamics simulations to study the macrolides erythromycin and azithromycin in wild-type, A2058G-mutated, and singly or doubly A2058-methylated Escherichia coli ribosomes. We find that the ribosomal modifications result in less favorable interactions between the base 2058 and the desosamine sugar of the macrolides, as well as greater displacement of the macrolides from their crystal structure position, illuminating the causes of resistance. We have also examined four azithromycin derivatives containing aromatic indole-analog moieties, which were previously designed based on simulations of the stalling peptide SecM in the ribosome. Surprisingly, we found that the studied moieties could adopt very different geometries when interacting with a key base in the tunnel, A751, possibly explaining their distinct activities. Based on our simulations, we propose modifications to the indole-analog moieties that should increase their interactions with A751 and, consequently, enhance the potency of future azithromycin derivatives.

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Reviving Antibiotics: Efflux Pump Inhibitors That Interact with AcrA, a Membrane Fusion Protein of the AcrAB-TolC Multidrug Efflux Pump

Cited by 99 publications

References 40 publications

Antimicrobial Resistance, Biofilm Formation, and Phylogenetic Grouping of Uropathogenic Escherichia coli Isolates in Egypt: The Role of Efflux Pump-Mediated Resistance

Antimicrobial Resistance, Biofilm Formation, and Phylogenetic Grouping of Uropathogenic Escherichia coli Isolates in Egypt: The Role of Efflux Pump-Mediated Resistance

Identification and Structure–Activity Relationships of Novel Compounds that Potentiate the Activities of Antibiotics in Escherichia coli

Toward the rational design of macrolide antibiotics to combat resistance

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