Genetic Resistance Determinants, In Vitro Time-Kill Curve Analysis and Pharmacodynamic Functions for the Novel Topoisomerase II Inhibitor ETX0914 (AZD0914) in Neisseria gonorrhoeae

Foerster, Sunniva; Golparian, Daniel; Jacobsson, Susanne; Hathaway, Lucy J.; Low, Nicola; Shafer, William M.; Althaus, Christian L.; Unemo, Magnus

doi:10.3389/fmicb.2015.01377

Cited by 46 publications

(61 citation statements)

References 36 publications

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“…2). The rate of bactericidal activity was similar or superior to that for ciprofloxacin and other NBTIs reported in the literature (27,33,34). Interestingly, REDX06213 caused a similar rate of bactericidal activity at 4ϫ and 8ϫ MIC, indicating time-dependent rather than concentration-dependent killing.…”

Section: Discussionsupporting

confidence: 75%

Novel Bacterial Topoisomerase Inhibitors with Potent Broad-Spectrum Activity against Drug-Resistant Bacteria

Charrier

Salisbury

Savage

et al. 2017

Antimicrob Agents Chemother

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The novel bacterial topoisomerase inhibitor class is an investigational type of antibacterial inhibitor of DNA gyrase and topoisomerase IV that does not have cross-resistance with the quinolones. Here, we report the evaluation of the in vitro properties of a new series of this type of small molecule. Exemplar compounds selectively and potently inhibited the catalytic activities of Escherichia coli DNA gyrase and topoisomerase IV but did not block the DNA breakage-reunion step. Compounds showed broad-spectrum inhibitory activity against a wide range of Grampositive and Gram-negative pathogens, including biodefence microorganisms and Mycobacterium tuberculosis. No cross-resistance with fluoroquinolone-resistant Staphylococcus aureus and E. coli isolates was observed. Measured MIC 90 values were 4 and 8 g/ml against a panel of contemporary multidrug-resistant isolates of Acinetobacter baumannii and E. coli, respectively. In addition, representative compounds exhibited greater antibacterial potency than the quinolones against obligate anaerobic species. Spontaneous mutation rates were low, with frequencies of resistance typically Ͻ10 Ϫ8 against E. coli and A. baumannii at concentrations equivalent to 4-fold the MIC. Compound-resistant E. coli mutants that were isolated following serial passage were characterized by whole-genome sequencing and carried a single Arg38Leu amino acid substitution in the GyrA subunit of DNA gyrase. Preliminary in vitro safety data indicate that the series shows a promising therapeutic index and potential for low human ether-a-go-go-related gene (hERG) inhibition (50% inhibitory concentration [IC 50 ], Ͼ100 M). In summary, the compounds' distinct mechanism of action relative to the fluoroquinolones, whole-cell potency, low potential for resistance development, and favorable in vitro safety profile warrant their continued investigation as potential broad-spectrum antibacterial agents.

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Section: Discussionsupporting

confidence: 75%

Novel Bacterial Topoisomerase Inhibitors with Potent Broad-Spectrum Activity against Drug-Resistant Bacteria

Charrier

Salisbury

Savage

et al. 2017

Antimicrob Agents Chemother

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“…Neisseria gonorrhoeae has developed resistance to all antimicrobials currently available [2, 3], and there are only a few novel antibiotics in development [4-6], therefore new approaches are urgently needed. A recently described approach calls for targeted therapy with antibiotics previously thought to be ineffective [7, 8], which has been made possible by the development of rapid molecular assays that predict in vitro antimicrobial susceptibility [9].…”

Section: Introductionmentioning

confidence: 99%

Wild-Type Gyrase A Genotype of Neisseria gonorrhoeae Predicts In Vitro Susceptibility to Ciprofloxacin: A Systematic Review of the Literature and Meta-Analysis

Allan‐Blitz¹,

Wang²,

Klausner³

2017

Sexual Trans Dis

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Multidrug-resistant Neisseria gonorrhoeae infections have been declared one of the top three urgent threats to public health. Approaches to combat resistance include targeted therapy with antibiotics previously thought to be ineffective, made possible by rapid molecular assays to predict susceptibility. Previous studies have associated the gyrase A (gyrA) gene of Neisseria gonorrhoeae with in vitro resistance to ciprofloxacin. We conducted a systematic review of studies comparing Neisseria gonorrhoeae gyrA genotype results with conventional antimicrobial susceptibility test results. We identified 31 studies meeting inclusion criteria, among which seven different loci for mutations in the gyrA gene were identified, from sixteen countries between the years of 1996 and 2016. We then performed a meta-analysis among those studies stratifying by use of real-time PCR or non-real-time PCR technique, and compared the summary receiver operating characteristic curves (sROC) between the two PCR methods. Among studies using real-time PCR the pooled estimate of sensitivity and specificity of gyrA genotype results for the prediction of Neisseria gonorrhoeae susceptibility to ciprofloxacin were 98.2% (95% CI 96.5%-99.1%) and 98.6% (95% CI 97.0%-99.3%), respectively. The sROCs for studies using real-time PCR techniques were well separated from those using non-real-time PCR techniques, with only slight overlap in the confidence intervals, suggesting that real-time PCR techniques were a more accurate approach. GyrA genotype testing is a novel approach to combating the emergence of multi drug-resistant Neisseria gonorrhoeae, and is a sensitive and specific method to predict in vitro ciprofloxacin susceptibility.

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“…Initially, our screening workflow was based on the timekill experiments performed by Foerster et al (52), who suspended N. gonorrhoeae in phosphate-buffered saline to a turbidity equivalent to a 0.5 McFarland standard and then inoculated 15 ml of GW medium with 30 l of suspension. The inoculum was dispensed into microtiter plates and grown for 4 h, at which point antibiotics were added, and cultures were grown up to 6 h longer (52). However, we were unable to achieve consistent, reliable growth with this method using N. gonorrhoeae strain FA1090, likely due to the various degrees of cell lysis observed between different gonococci (58-62) as well as of our knockout strains.…”

mentioning

confidence: 98%

“…Additionally, it has been successfully utilized to establish a time course of bacterial killing with antibiotics of different mechanisms of action (52).…”

mentioning

confidence: 99%

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

et al. 2017

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The function and extracellular location of cell envelope proteins make them attractive candidates for developing vaccines against bacterial diseases, including challenging drug-resistant pathogens, such as Neisseria gonorrhoeae. A proteomicsdriven reverse vaccinology approach has delivered multiple gonorrhea vaccine candidates; however, the biological functions of many of them remain to be elucidated. Herein, the functions of six gonorrhea vaccine candidates-NGO2121, NGO1985, NGO2054, NGO2111, NGO1205, and NGO1344 -in cell envelope homeostasis were probed using phenotype microarrays under 1,056 conditions and a ΔbamE mutant (Δngo1780) as a reference of perturbed outer membrane integrity. Optimal growth conditions for an N. gonorrhoeae phenotype microarray assay in defined liquid medium were developed, which can be useful in other applications, including rapid and thorough antimicrobial susceptibility assessment. Our studies revealed 91 conditions having uniquely positive or negative effects on one of the examined mutants. A cluster analysis of 37 and 57 commonly beneficial and detrimental compounds, respectively, revealed three separate phenotype groups: NGO2121 and NGO1985; NGO1344 and BamE; and the trio of NGO1205, NGO2111, and NGO2054, with the last protein forming an independent branch of this cluster. Similar phenotypes were associated with loss of these vaccine candidates in the highly antibiotic-resistant WHO X strain. Based on their extensive sensitivity phenomes, NGO1985 and NGO2121 appear to be the most promising vaccine candidates. This study establishes the principle that phenotype microarrays can be successfully applied to a fastidious bacterial organism, such as N. gonorrhoeae. IMPORTANCE Innovative approaches are required to develop vaccines against prevalent and neglected sexually transmitted infections, such as gonorrhea. Herein, we have utilized phenotype microarrays in the first such investigation into Neisseria gonorrhoeae to probe the function of proteome-derived vaccine candidates in cell envelope homeostasis. Information gained from this screening can feed the vaccine candidate decision tree by providing insights into the roles these proteins play in membrane permeability, integrity, and overall N. gonorrhoeae physiology. The optimized screening protocol can be applied in investigations into the function of other hypothetical proteins of N. gonorrhoeae discovered in the expanding number of whole-genome sequences, in addition to revealing phenotypic differences between clinical and laboratory strains.KEYWORDS Neisseria gonorrhoeae, vaccine antigens, cell envelope, phenotypic microarrays, antibiotics, Biolog I n Gram-negative bacteria, the cell envelope is composed of the outer membrane, the cell wall, and the cytoplasmic or inner membrane, each of which can be further broken down into its constituents (1). The outer membrane is a bilayer composed of a lipopolysaccharide (LPS) or lipooligosaccharide (LOS) outer leaflet facing the extracel-

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Genetic Resistance Determinants, In Vitro Time-Kill Curve Analysis and Pharmacodynamic Functions for the Novel Topoisomerase II Inhibitor ETX0914 (AZD0914) in Neisseria gonorrhoeae

Cited by 46 publications

References 36 publications

Novel Bacterial Topoisomerase Inhibitors with Potent Broad-Spectrum Activity against Drug-Resistant Bacteria

Novel Bacterial Topoisomerase Inhibitors with Potent Broad-Spectrum Activity against Drug-Resistant Bacteria

Wild-Type Gyrase A Genotype of Neisseria gonorrhoeae Predicts In Vitro Susceptibility to Ciprofloxacin: A Systematic Review of the Literature and Meta-Analysis

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

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