scholarly journals Quinolone-resistant Neisseria gonorrhoeae: correlation of alterations in the GyrA subunit of DNA gyrase and the ParC subunit of topoisomerase IV with antimicrobial susceptibility profiles.

1996 ◽  
Vol 40 (4) ◽  
pp. 1020-1023 ◽  
Author(s):  
T Deguchi ◽  
M Yasuda ◽  
M Nakano ◽  
S Ozeki ◽  
T Ezaki ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Susceptibility ◽  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Clinical Strains ◽  
Susceptibility Profiles

Fifty-five clinical strains of Neisseria gonorrhoeae were examined for mutations in the gyrA and parC genes and for antimicrobial susceptibility profiles. The MICs of quinolones for 31 strains with alterations in GyrA were significantly higher than the MICs for 24 strains without such alterations. Eleven strains with alterations in both GyrA and ParC were significantly more resistant to fluoroquinolones than those with alterations in GyrA alone. The MICs of cephalosporins for these strains were also significantly higher than those for other strains.

Activities of Trovafloxacin Compared with Those of Other Fluoroquinolones against Purified Topoisomerases and gyrA and grlA Mutants ofStaphylococcus aureus

1999 ◽  
Vol 43 (8) ◽  
pp. 1845-1855 ◽  
Author(s):  
Thomas D. Gootz ◽  
Richard P. Zaniewski ◽  
Suzanne L. Haskell ◽  
Frank S. Kaczmarek ◽  
Alison E. Maurice
Keyword(s):  
Dna Cleavage ◽  
Dna Gyrase ◽  
The Other ◽  
Second Step ◽  
Ofstaphylococcus Aureus ◽  
Topoisomerase Iv ◽  
Direct Plating ◽  
Clinical Strains ◽  
Plating Method ◽  
Susceptibility Breakpoint

ABSTRACT Frequencies of mutation to resistance with trovafloxacin and four other quinolones were determined with quinolone-susceptibleStaphylococcus aureus RN4220 by a direct plating method. First-step mutants were selected less frequently with trovafloxacin (1.1 × 10−10 at 2 to 4× the MIC) than with levofloxacin or ciprofloxacin (3.0 × 10−7 to 3.0 × 10−8 at 2 to 4× the MIC). Mutants with a change in GrlA (Ser80→Phe or Tyr) were most commonly selected with trovafloxacin, ciprofloxacin, levofloxacin, or pefloxacin. First-step mutants were difficult to select with sparfloxacin; however, second-step mutants with mutations in gyrA were easily selected when a preexisting mutation in grlA was present. Against 29 S. aureus clinical isolates with known mutations in gyrA and/or grlA, trovafloxacin was the most active quinolone tested (MIC at which 50% of isolates are inhibited [MIC50] and MIC90, 1 and 4 μg/ml, respectively); in comparison, MIC50s and MIC90s were 32 and 128, 16 and 32, 8 and 32, and 128 and 256 μg/ml for ciprofloxacin, sparfloxacin, levofloxacin, and pefloxacin, respectively. Strains with a mutation in grlA only were generally susceptible to all of the quinolones tested. For mutants with changes in both grlA and gyrA MICs were higher and were generally above the susceptibility breakpoint for ciprofloxacin, sparfloxacin, levofloxacin, and pefloxacin. Addition of reserpine (20 μg/ml) lowered the MICs only of ciprofloxacin fourfold or more for 18 of 29 clinical strains. Topoisomerase IV and DNA gyrase genes were cloned from S. aureus RN4220 and from two mutants with changes in GrlA (Ser80→Phe and Glu84→Lys). The enzymes were overexpressed in Escherichia coli GI724, purified, and used in DNA catalytic and cleavage assays that measured the relative potency of each quinolone. Trovafloxacin was at least five times more potent than ciprofloxacin, sparfloxacin, levofloxacin, or pefloxacin in stimulating topoisomerase IV-mediated DNA cleavage. While all of the quinolones were less potent in cleavage assays with the altered topoisomerase IV, trovafloxacin retained its greater potency relative to those of the other quinolones tested. The greater intrinsic potency of trovafloxacin against the lethal topoisomerase IV target in S. aureus contributes to its improved potency against clinical strains of S. aureus that are resistant to other quinolones.

IN VITRO SELECTION OF FLUOROQUINOLONE-RESISTANT NEISSERIA GONORRHOEAE HARBORING ALTERATIONS IN DNA GYRASE AND TOPOISOMERASE IV

2000 ◽  
pp. 847-851
Author(s):  
MITSURU YASUDA ◽  
HIDEYUKI FUKUDA ◽  
SHIGEAKI YOKOI ◽  
SATOSHI ISHIHARA ◽  
YUKIMICHI KAWADA ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
In Vitro Selection ◽  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Selection Of

scholarly journals NG-STAR genotypes are associated with MDR in Neisseria gonorrhoeae isolates collected in 2017 in Shanghai

2019 ◽  
Vol 75 (3) ◽  
pp. 566-570 ◽  
Author(s):  
Yijing Yang ◽  
Yang Yang ◽  
Irene Martin ◽  
Yuan Dong ◽  
Nannan Diao ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Neisseria Gonorrhoeae ◽  
Antimicrobial Susceptibility ◽  
Mlst Analysis ◽  
High Prevalence ◽  
Star Database ◽  
Susceptibility Profiles

Abstract Objectives To determine the association of Neisseria gonorrhoeae antimicrobial resistance and genotypes using N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR). Methods We characterized 124 N. gonorrhoeae isolates for their antimicrobial susceptibility profiles and NG-STAR ST characteristics using the guidelines of CLSI and EUCAST. The NG-STAR STs of seven loci were analysed. N. gonorrhoeae multiantigen sequence typing (NG-MAST) and MLST analysis was conducted in isolates with specific NG-STAR STs. Results NG-STAR differentiated 124 N. gonorrhoeae isolates into 84 STs, of which 66 STs were novel to the NG-STAR database. NG-STAR ST-199, ST-348, ST-428, ST-497 and ST-1138 were the predominant STs. Three N. gonorrhoeae isolates with ceftriaxone and cefixime MICs ≥1.0 mg/L were grouped as NG-STAR ST-233. NG-STAR ST-202 isolates (n=4) were associated with high azithromycin MICs and had an identical NG-MAST ST. The NG-STAR ST-348 group (n=5) comprised more isolates with reduced susceptibility to cefixime (n=4) than cefixime-susceptible isolates (n=1). Conclusions NG-STAR analysis differentiated N. gonorrhoeae isolates in settings with a high prevalence of antimicrobial resistance. Specific NG-STAR STs are associated with reduced susceptibility to ceftriaxone or cefixime and resistance to azithromycin in N. gonorrhoeae.

scholarly journals Inhibition of Neisseria gonorrhoeae Type II Topoisomerases by the Novel Spiropyrimidinetrione AZD0914

2015 ◽  
Vol 290 (34) ◽  
pp. 20984-20994 ◽  
Author(s):  
Gunther Kern ◽  
Tiffany Palmer ◽  
David E. Ehmann ◽  
Adam B. Shapiro ◽  
Beth Andrews ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Bacterial Species ◽  
Dna Gyrase ◽  
Resistant Mutant ◽  
Multidrug Resistant ◽  
Type Ii ◽  
Topoisomerase Iv ◽  
Gram Positive ◽  
Gram Negative

We characterized the inhibition of Neisseria gonorrhoeae type II topoisomerases gyrase and topoisomerase IV by AZD0914 (AZD0914 will be henceforth known as ETX0914 (Entasis Therapeutics)), a novel spiropyrimidinetrione antibacterial compound that is currently in clinical trials for treatment of drug-resistant gonorrhea. AZD0914 has potent bactericidal activity against N. gonorrhoeae, including multidrug-resistant strains and key Gram-positive, fastidious Gram-negative, atypical, and anaerobic bacterial species (Huband, M. D., Bradford, P. A., Otterson, L. G., Basrab, G. S., Giacobe, R. A., Patey, S. A., Kutschke, A. C., Johnstone, M. R., Potter, M. E., Miller, P. F., and Mueller, J. P. (2014) In Vitro Antibacterial Activity of AZD0914: A New Spiropyrimidinetrione DNA Gyrase/Topoisomerase Inhibitor with Potent Activity against Gram-positive, Fastidious Gram-negative, and Atypical Bacteria. Antimicrob. Agents Chemother. 59, 467–474). AZD0914 inhibited DNA biosynthesis preferentially to other macromolecules in Escherichia coli and induced the SOS response to DNA damage in E. coli. AZD0914 stabilized the enzyme-DNA cleaved complex for N. gonorrhoeae gyrase and topoisomerase IV. The potency of AZD0914 for inhibition of supercoiling and the stabilization of cleaved complex by N. gonorrhoeae gyrase increased in a fluoroquinolone-resistant mutant enzyme. When a mutation, conferring mild resistance to AZD0914, was present in the fluoroquinolone-resistant mutant, the potency of ciprofloxacin for inhibition of supercoiling and stabilization of cleaved complex was increased greater than 20-fold. In contrast to ciprofloxacin, religation of the cleaved DNA did not occur in the presence of AZD0914 upon removal of magnesium from the DNA-gyrase-inhibitor complex. AZD0914 had relatively low potency for inhibition of human type II topoisomerases α and β.

scholarly journals 1249. Genetic Evidence That Gepotidacin Shows Well-balanced Dual Targeting against DNA Gyrase And Topoisomerase IV in Neisseria gonorrhoeae

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S642-S643
Author(s):  
Pan Chan ◽  
Karen Ingraham ◽  
Sharon Min ◽  
Nicole Scangarella-Oman ◽  
Steve Rittenhouse ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Fold Increase ◽  
Dna Gyrase ◽  
Dose Selection ◽  
Topoisomerase Iv ◽  
Resistance Development ◽  
Phase 2 Trial ◽  
Dual Targeting ◽  
Clinical Resistance

Abstract Background Gepotidacin (GEP) is a novel triazaacenaphthylene bacterial type II topoisomerase inhibitor targeting both bacterial DNA gyrase and topoisomerase IV by a different mechanism from fluoroquinolone antibiotics. Although in vitro frequency of resistance to GEP in Neisseria gonorrhoeae (NG) is low, during a phase 2 trial, clinical resistance to gepotidacin in NG emerged in a subset of fluoroquinolone-resistant NG isolates that contained a pre-existing ParC D86N mutation by introduction of a new GyrA A92T mutation. The objective of this study was to evaluate the role of GyrA A92T & Parc D86N mutations in resistance to GEP. Methods We utilized the high frequency of natural transformation to introduce GyrA A92T and ParC D86N mutations, individually and in combination, into NG isolates either with GyrA S91F D95G mutations or with wild type (WT) GyrA by selection on ciprofloxacin (CIP) or GEP to generate isogenic strains for susceptibility evaluation. Results Results are summarized in enclosed table. Overall, GyrA A92T and ParC D86N mutations alone did not confer a significant (>4-fold) increase in GEP MIC; whereas together they gave >16-fold increases in GEP MIC. Importantly, quinolone target mutations (GyrA S91F D95G and ParC D86N) together showed no significant effect on the GEP MIC; while they gave >1000-fold increase in CIP MIC. As expected, GyrA A92T and ParC D86N mutations alone or together in WT GyrA background had no significant effect on CIP susceptibility. Susceptibility of isogenic NG strains to gepotidacin and ciprofloxacin Conclusion Our results indicated that unlike fluoroquinolones that primarily target DNA gyrase in NG, there is no obvious primary target for GEP, supporting well-balanced dual targeting of DNA gyrase and topoisomerase IV by GEP in NG. Though, the pre-existing ParC D86N mutation is a potential risk marker for clinical resistance development, as this mutation compromises dual targeting of GEP, our studies provide mechanistic insight for appropriate clinical dose selection to potentially suppress further resistance development in this subset of clinical isolates. Disclosures Pan Chan, PhD, GlaxoSmithKline (Employee, Shareholder) Karen Ingraham, MS, GlaxoSmithKline (Employee, Shareholder) Sharon Min, MS, GlaxoSmithKline (Employee, Shareholder) Nicole Scangarella-Oman, MS, GlaxoSmithKline plc. (Employee, Shareholder) Steve Rittenhouse, PhD, GlaxoSmithKline (Employee, Shareholder) Jianzhong Huang, PhD, GlaxoSmithKline (Employee, Shareholder)

Antimicrobial Susceptibility of Neisseria gonorrhoeae in Adult Patients Seeking Care at Military Hospitals in Thailand From 2014 to 2020

2022 ◽  
Author(s):  
Maneerat Somsri ◽  
Wilawan Oransathid ◽  
Brian Vesely ◽  
Mariusz Wojnarski ◽  
Samandra Demons ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Susceptibility ◽  
Generation Cephalosporin ◽  
Multidrug Resistant ◽  
Fourth Generation ◽  
Walter Reed Army Institute ◽  
Medical Department ◽  
Military Hospitals ◽  
Silver Spring ◽  
Susceptibility Profiles

ABSTRACT Introduction The effective dual antibiotics ceftriaxone (CRO) and azithromycin (AZM) have successfully treated Neisseria gonorrhoeae (GC) infection, however, the CRO- and AZM-resistant strains have been sporadically detected globally and in Thailand. Furthermore, there are no currently antimicrobial susceptibility profiles of the GC isolates obtained from soldiers reported in Thailand. Hence, this is the first study to describe the antimicrobial susceptibility profiles of GC isolates obtained from predominately soldiers who seeking care at Military Camp Hospitals, in Thailand from 2014 to 2020. Materials and Methods A total of 624 symptomatic gonococcal samples were received from 10 military hospitals during 2014-2020. They were collected from urethral swabs and inoculated into selective media. The suspected GC isolates were subcultured and presumptively identified using conventional microbiology techniques. Antimicrobial susceptibility test was performed by Etest to determine minimal inhibitory concentration (μg/mL) against AZM, benzylpenicillin, cefepime, cefixime, ceftriaxone (CRO), ciprofloxacin, spectinomycin, and tetracycline using the criteria outlined in the Clinical and Laboratory Standards Institute guidelines. This study was approved by Institutional Review Board, Royal Thai Army Medical Department under protocol number S036b/56 and Walter Reed Army Institute of Research, and Silver Spring, MD under protocol number WR #2039. Results A total of 624 samples were collected from symptomatic gonococcal infectious patients with 91.5% (571/624) of samples obtained from soldiers. Of those, 78% (488/624) were identified as GC and 92% (449/488) of them were isolated from soldiers. All GC samples collected were susceptible to CRO (first-line treatment) with only one GC isolate identified as non-susceptible to cefepime and three isolates identified as non-susceptible to AZM. Conclusion The recommended dual treatment of GC infections with CRO and AZM is currently an effective empirical treatment for patients who are seeking care at military hospitals in Thailand. Nevertheless, cefepime is a fourth-generation cephalosporin with documented high activity against GC strains equal to other “third-generation” cephalosporins such as CRO. Due to the active duty of military personnel, they concerned about the confidentiality and frequently seek treatment at civilian clinics. Additionally, due to the availability of antibiotics over the counter in Thailand, many choose the option to self-medicate without a physician’s prescription. These could be subsequently driven the gradual increase of multidrug-resistant gonococcal strains throughout the country. Thus, the GC surveillance would be needed for further Force Health Protection and public health authorities in response to the drug-resistant GC threats.

scholarly journals Characterization of the Novel DNA Gyrase Inhibitor AZD0914: Low Resistance Potential and Lack of Cross-Resistance in Neisseria gonorrhoeae

2014 ◽  
Vol 59 (3) ◽  
pp. 1478-1486 ◽  
Author(s):  
Richard A. Alm ◽  
Sushmita D. Lahiri ◽  
Amy Kutschke ◽  
Linda G. Otterson ◽  
Robert E. McLaughlin ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Oral Treatment ◽  
Bacterial Species ◽  
Treatment Options ◽  
Dna Gyrase ◽  
Cross Resistance ◽  
Topoisomerase Iv ◽  
Content Type

ABSTRACTThe unmet medical need for novel intervention strategies to treatNeisseria gonorrhoeaeinfections is significant and increasing, as rapidly emerging resistance in this pathogen is threatening to eliminate the currently available treatment options. AZD0914 is a novel bacterial gyrase inhibitor that possesses potentin vitroactivities against isolates with high-level resistance to ciprofloxacin and extended-spectrum cephalosporins, and it is currently in clinical development for the treatment ofN. gonorrhoeaeinfections. The propensity to develop resistance against AZD0914 was examined inN. gonorrhoeaeand found to be extremely low, a finding supported by similar studies withStaphylococcus aureus. The genetic characterization of both first-step and second-step mutants that exhibited decreased susceptibilities to AZD0914 identified substitutions in the conserved GyrB TOPRIM domain, confirming DNA gyrase as the primary target of AZD0914 and providing differentiation from fluoroquinolones. The analysis of available bacterial gyrase and topoisomerase IV structures, including those bound to fluoroquinolone and nonfluoroquinolone inhibitors, has allowed the rationalization of the lack of cross-resistance that AZD0914 shares with fluoroquinolones. Microbiological susceptibility data also indicate that the topoisomerase inhibition mechanisms are subtly different betweenN. gonorrhoeaeand other bacterial species. Taken together, these data support the progression of AZD0914 as a novel treatment option for the oral treatment ofN. gonorrhoeaeinfections.

scholarly journals In Vitro and In Vivo Activities of TP0480066, a Novel Topoisomerase Inhibitor, against Neisseria gonorrhoeae

2021 ◽  
Author(s):  
Aiko Masuko ◽  
Iichiro Takata ◽  
Kiyoko Fujita ◽  
Hirotoshi Okumura ◽  
Fumihito Ushiyama ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Agent ◽  
Transmitted Disease ◽  
Dna Gyrase ◽  
Multidrug Resistant ◽  
Cross Resistance ◽  
Topoisomerase Iv ◽  
Sexually Transmitted

Gonorrhea is a common, sexually transmitted disease caused by Neisseria gonorrhoeae. Multidrug-resistant N. gonorrhoeae is an urgent threat, and the development of a new antimicrobial agent that functions via a new mechanism is strongly desired. We evaluated the in vitro and in vivo activities of a DNA gyrase/topoisomerase IV inhibitor, TP0480066, which is a novel 8-(methylamino)-2-oxo-1,2-dihydroquinoline derivative. The MICs of TP0480066 were substantially lower than those of other currently or previously used antimicrobials against gonococcal strains demonstrating resistance to fluoroquinolones, macrolides, β-lactams and aminoglycosides (MICs, ≤0.0005 μg/mL). Additionally, no cross-resistance was observed between TP0480066 and ciprofloxacin. The frequencies of spontaneous resistance to TP0480066 for N. gonorrhoeae ATCC 49226 were below the detection limit (<2.4 × 10−10) at concentrations equivalent to 32 × MIC. TP0480066 also showed potent in vitro bactericidal activity and in vivo efficacy in a mouse model of N. gonorrhoeae infection. These data suggest that TP0480066 is a candidate antimicrobial agent for gonococcal infections.

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