Comparison of Cytomegalovirus Terminase Gene Mutations Selected after Exposure to Three Distinct Inhibitor Compounds

ABSTRACT Letermovir, GW275175X (a benzimidazole), and tomeglovir (Bay38-4766) are chemically unrelated human cytomegalovirus (CMV) terminase complex inhibitors that have been tested in human subjects. UL56 gene mutations are the dominant pathway of letermovir resistance, while UL89 and UL56 mutations are known to confer benzimidazole resistance. This study compares the mutations elicited by the three inhibitors during in vitro CMV propagation. GW275175X consistently selected for UL89 D344E and sometimes selected for UL89 C347S, UL89 R351H, or UL56 Q204R. Tomeglovir consistently selected for UL89 V362M and sometimes selected for UL89 N329S, T350M, H389N, or N405D or UL56 L208M, E407D, H637Q, or V639M. Adding to known and novel UL56 mutations, letermovir occasionally selected for UL89 N320H, D344E, or M359I. Recombinant phenotyping confirmed that UL89 D344E conferred 9-fold resistance (an increased 50% effective concentration [EC50]) for GW275175X and increased the letermovir and tomeglovir EC50s by 1.7- to 2.1-fold for the baseline virus and the UL56 Q204R, E237D, F261L, and M329T mutants. UL89 N320H and M359I conferred <2-fold letermovir resistance but 7-fold tomeglovir resistance; the N320H mutant was also 4-fold resistant to GW275175X. UL89 N329S conferred tomeglovir and letermovir cross-resistance. UL89 T350M conferred resistance to all three inhibitors. UL89 C347S conferred 27-fold GW275175X resistance. UL89 V362M and H389N conferred 98-fold and 29-fold tomeglovir resistance, respectively, without conferring cross-resistance. Thus, characteristic UL89 mutations confer substantial resistance to GW275175X and tomeglovir and are an uncommon accessory pathway of letermovir resistance. Instances of moderate cross-resistance and the proximity of the selected UL89 and UL56 mutations suggest targeting of a similar terminase functional locus involving UL56 and UL89 interaction.

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Cytomegalovirus Mutants Resistant to Ganciclovir and Cidofovir Differ in Susceptibilities to Synguanol and Its 6-Ether and 6-Thioether Derivatives

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02544-13 ◽

2013 ◽

Vol 58 (3) ◽

pp. 1809-1812 ◽

Cited By ~ 8

Author(s):

Sunwen Chou ◽

Gloria Komazin-Meredith ◽

John D. Williams ◽

Terry L. Bowlin

Keyword(s):

Dna Polymerase ◽

Human Cytomegalovirus ◽

Effective Concentration ◽

Cross Resistance ◽

Wild Type ◽

Viral Dna ◽

Exonuclease Domain ◽

Concentration Ratios

ABSTRACTThe methylenecyclopropane nucleoside (MCPN) analogs synguanol and its 6-alkoxy (MBX2168) and 6-alkylthio (MBX1616) derivatives retained goodin vitroactivities against several common ganciclovir-resistant UL97 kinase variants of human cytomegalovirus. Foscarnet-MCPN cross-resistance was observed among UL54 polymerase variants. UL54 exonuclease domain ganciclovir-cidofovir dual-resistant variants were remarkably more hypersensitive to these MCPNs than to cyclopropavir, with some 50% effective concentration ratios that were <0.1× the wild type. Different categories of MCPNs may have therapeutically exploitable mechanistic differences in viral DNA polymerase inhibition.

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Novel Cytomegalovirus UL54 DNA Polymerase Gene Mutations SelectedIn VitroThat Confer Brincidofovir Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00214-16 ◽

2016 ◽

Vol 60 (6) ◽

pp. 3845-3848 ◽

Cited By ~ 13

Author(s):

Sunwen Chou ◽

Ronald J. Ercolani ◽

E. Randall Lanier

Keyword(s):

Dna Polymerase ◽

Gene Mutations ◽

Cross Resistance ◽

The Novel ◽

Resistance Mutations ◽

Single Instance ◽

Selection Experiments ◽

Exonuclease Domain ◽

Domain I

Eightin vitroselection experiments under brincidofovir pressure elicited the known cytomegalovirus DNA polymerase amino acid substitutions N408K and V812L and the novel exonuclease domain substitutions D413Y, E303D, and E303G, which conferred ganciclovir and cidofovir resistance with 6- to 11-fold resistance to brincidofovir or 17-fold when E303G was combined with V812L. The new exonuclease domain I resistance mutations selected under brincidofovir pressure add to the single instance previously reported and show the expected patterns of cross-resistance.

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Differential Effect of SdhB Gene Mutations on the Sensitivity to SDHI Fungicides in Botrytis cinerea

Plant Disease ◽

10.1094/pdis-03-12-0322-re ◽

2013 ◽

Vol 97 (1) ◽

pp. 118-122 ◽

Cited By ~ 71

Author(s):

Thomas Veloukas ◽

Anastasios N. Markoglou ◽

George S. Karaoglanidis

Keyword(s):

Succinate Dehydrogenase ◽

Botrytis Cinerea ◽

Gene Mutations ◽

Gray Mold ◽

Cross Resistance ◽

Low Resistance ◽

Resistance Patterns ◽

Increased Sensitivity ◽

High Control

Succinate dehydrogenase inhibiting (SDHI) fungicides constitute a relatively novel fungicide group used for gray mold control caused mainly by Botrytis cinerea. Shortly after registration, resistance was observed in fungal populations that correlated with several mutations in the succinate dehydrogenase complex (complex II). In the current study, 30 B. cinerea isolates possessing five different mutations at three different codons of SdhB (P225F, N230I, and H272L/R/Y) were characterized for their sensitivities to eight SDHI fungicides. The results show different sensitivities and cross-resistance patterns between structurally different SDHIs. P225F mutants were resistant in vitro to all SDHIs tested. Similarly, isolates possessing the H272L mutation were highly resistant to boscalid but showed low to moderate levels of resistance to other SDHIs. The N230I mutants were moderately resistant to boscalid, fluopyram, and fluxapyroxad and showed low resistance levels to isopyrazam, bixafen, fenfuram, benodanil, and carboxin. The H272R mutants showed moderate levels of resistance to boscalid and low resistance levels to isopyrazam, fenfuram, and carboxin but remained sensitive to fluopyram, bixafen, fluxapyroxad, and benodanil. Similarly, the H272Y showed moderate levels of resistance to boscalid and very low resistance levels to isopyrazam, bixafen, fenfuram, and carboxin but showed increased sensitivity to benodanil and fluopyram. Boscalid provided moderate to high control of H272R/Y and N230I mutants in detached fruit assays but provided little control against the H272L and P225F mutants. In contrast, fluopyram controlled H272R/Y mutants and provided moderate levels of control toward H272L, N230I, and P225F mutants. Our findings suggest that sensitivity to SDHIs may vary greatly, dependent on the point mutation in the sdhb subunit.

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Murine cytomegalovirus resistant to antivirals has genetic correlates with human cytomegalovirus

Journal of General Virology ◽

10.1099/vir.0.80910-0 ◽

2005 ◽

Vol 86 (8) ◽

pp. 2141-2151 ◽

Cited By ~ 7

Author(s):

G. M. Scott ◽

H.-L. Ng ◽

C. J. Morton ◽

M. W. Parker ◽

W. D. Rawlinson

Keyword(s):

Protein Kinase ◽

Dna Polymerase ◽

Human Cytomegalovirus ◽

Murine Cytomegalovirus ◽

Cross Resistance ◽

Antiviral Resistance ◽

Three Dimensional Model ◽

Mcmv Infection

Human cytomegalovirus (HCMV) resistance to antivirals is a significant clinical problem. Murine cytomegalovirus (MCMV) infection of mice is a well-described animal model for in vivo studies of CMV pathogenesis, although the mechanisms of MCMV antiviral susceptibility need elucidation. Mutants resistant to nucleoside analogues aciclovir, adefovir, cidofovir, ganciclovir, penciclovir and valaciclovir, and the pyrophosphate analogue foscarnet were generated by in vitro passage of MCMV (Smith) in increasing concentrations of antiviral. All MCMV antiviral resistant mutants contained DNA polymerase mutations identical or similar to HCMV DNA polymerase mutations known to confer antiviral resistance. Mapping of the mutations onto an MCMV DNA polymerase three-dimensional model generated using the Thermococcus gorgonarius Tgo polymerase crystal structure showed that the DNA polymerase mutations potentially confer resistance through changes in regions surrounding a catalytic aspartate triad. The ganciclovir-, penciclovir- and valaciclovir-resistant isolates also contained mutations within MCMV M97 identical or similar to recognized GCV-resistant mutations of HCMV UL97 protein kinase, and demonstrated cross-resistance to antivirals of the same class. This strongly suggests that MCMV M97 has a similar role to HCMV UL97 in the phosphorylation of nucleoside analogue antivirals. All MCMV mutants demonstrated replication-impaired phenotypes, with the lowest titre and plaque size observed for isolates containing mutations in both DNA polymerase and M97. These findings indicate DNA polymerase and protein kinase regions of potential importance for antiviral susceptibility and replication. The similarities between MCMV and HCMV mutations that arise under antiviral selective pressure increase the utility of MCMV as a model for in vivo studies of CMV antiviral resistance.

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Madu lebah kelulut (Trigona Spp.) dalam aktifitas terhadap bakteri Staphylococcus aureus resisten

Jurnal Skala Kesehatan ◽

10.31964/jsk.v9i1.151 ◽

2018 ◽

Vol 9 (1) ◽

Author(s):

Muhammad Ma'ruf ◽

Gina Alia Mawaddah ◽

Nisa Nur Agistni Eriana ◽

Farah Indah Swari ◽

Syaidatul Aslamiyah ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Inhibitory Concentration ◽

Minimum Bactericidal Concentration ◽

Effective Concentration ◽

Control Group ◽

Control Group Design ◽

Group Design ◽

Inhibitor Compounds ◽

Water Acidity

Infection caused by Staphylococcus aureus bacteria becomes a very serious problem because of the increased resistance of these bacteria to various types of antibiotics. Honey has antibacterial activity because it contains water, acidity and inhibitor compounds namely flavonoids. Honey can be produced Trigona spp. This study aims to Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) and effectiveness of honey bee kelulut (Trigona spp.) Against Staphylococcus aureus resistant cephalosporin bacteria in vitro. This research is true experiment with postest only control group design. The results of the study were measured by MIC showed no clarity at concentrations of 60 mg / ml, 70 mg / ml, 80 mg / ml, 90 mg / ml and and clarity at concentrations of 100 mg / ml, and MBC at concentrations of 60 mg / ml of 151 colonies, 70 mg / ml of 105 colonies, 80 mg / ml of 55 colonies, 90 mg / ml of 16 colonies and 100 mg / ml of 0 colonies. The effective concentration in killing Staphylococcus aureus resistant cephalosporin is 100 mg / ml

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Cytomegalovirus UL97 Mutations Affecting Cyclopropavir and Ganciclovir Susceptibility

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01259-10 ◽

2010 ◽

Vol 55 (1) ◽

pp. 382-384 ◽

Cited By ~ 29

Author(s):

Sunwen Chou ◽

Terry L. Bowlin

Keyword(s):

Effective Concentration ◽

Cross Resistance

ABSTRACTAmong the 7 most common UL97 mutations encountered in ganciclovir-resistant clinical cytomegalovirus isolates, the associated cyclopropavir cross-resistance varies from insignificant (L595S) to substantial (M460I and H520Q) as determined by recombinant phenotyping. Mutations M460I and H520Q were preferentially selectedin vitrounder cyclopropavir and conferred 12- to 20-fold increases in 50% effective concentration (EC50) values, while M460V, C592G, A594V, and C603W conferred 3- to 5-fold increases. Uncommon mutations M460T and C603R increased cyclopropavir EC50s by 8- to 10-fold.

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Human Cytomegalovirus UL97 Kinase Is Involved in the Mechanism of Action of Methylenecyclopropane Analogs with 6-Ether and -Thioether Substitutions

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01726-13 ◽

2013 ◽

Vol 58 (1) ◽

pp. 274-278 ◽

Cited By ~ 19

Author(s):

Gloria Komazin-Meredith ◽

Sunwen Chou ◽

Mark N. Prichard ◽

Caroll B. Hartline ◽

Steven C. Cardinale ◽

...

Keyword(s):

Human Cytomegalovirus ◽

Mechanism Of Action ◽

Fold Increase ◽

Cross Resistance ◽

Varicella Zoster ◽

Growth Defects ◽

Cytopathic Effects ◽

Simplex Virus

ABSTRACTMethylenecyclopropane nucleoside (MCPN) analogs are being investigated for treatment of human cytomegalovirus (HCMV) infection because of favorable preclinical data and limited ganciclovir cross-resistance. Monohydroxymethyl MCPNs bearing ether and thioether functionalities at the purine 6 position have antiviral activity against herpes simplex virus (HSV) and varicella-zoster virus (VZV) in addition to HCMV. The role of the HCMV UL97 kinase in the mechanism of action of these derivatives was examined. When tested against a kinase-inactive UL97 K355M virus, a moderate 5- to 7-fold increase in 50% effective concentration (EC50) was observed, in comparison to a 13- to 25-fold increase for either cyclopropavir or ganciclovir. Serial propagation of HCMV under two of these compounds selected for three novel UL97 mutations encoding amino acid substitutions D456N, C480R,and Y617del. When transferred to baseline laboratory HCMV strains, these mutations individually conferred resistance to all of the tested MCPNs, ganciclovir, and maribavir. However, the engineered strains also demonstrated severe growth defects and abnormal cytopathic effects similar to the kinase-inactive mutant. Expressed and purified UL97 kinase showedin vitrophosphorylation of the newly tested MCPNs. Thus, HCMV UL97 kinase is involved in the antiviral action of these MCPNs, but thein vitroselection of UL97-defective viruses suggests that their activity against more typical ganciclovir-resistant growth-competent UL97 mutants may be relatively preserved.

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New Locus of Drug Resistance in the Human Cytomegalovirus UL56 Gene Revealed byIn VitroExposure to Letermovir and Ganciclovir

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00922-18 ◽

2018 ◽

Vol 62 (9) ◽

Cited By ~ 23

Author(s):

Sunwen Chou ◽

L. Elizabeth Satterwhite ◽

Ronald J. Ercolani

Keyword(s):

Drug Resistance ◽

Human Cytomegalovirus ◽

Genetic Locus ◽

Gene Mutations ◽

Fold Increase ◽

Low Grade ◽

Cell Transplant ◽

Resistance Mutations ◽

Drug Concentrations

ABSTRACTLetermovir is a human cytomegalovirus (CMV) terminase inhibitor recently approved as prophylaxis in stem cell transplant recipients. In further studies of emerging drug resistance, a baseline laboratory CMV strain was serially propagated in cell culture under a combination of letermovir and ganciclovir. In eight experiments, UL56 terminase gene mutations were detected beginning at 10 passages and included novel amino acid substitutions V236A, L328V, and A365S in a region previously associated with letermovir resistance. Outside this region, the UL56 substitution C25F was detected at moderate drug concentrations in two experiments as either the first detected mutation or an addition to a preexisting V231L substitution. In all cases, mutation at UL56 codon 325 conferring absolute letermovir resistance eventually developed at a median of 20 passages. No UL97 kinase or UL54 DNA polymerase mutations relevant to ganciclovir resistance were detected until many passages after the first detection of the UL56 mutations. UL56 substitutions V236A, L328V, and A365S were shown to confer borderline or low-grade letermovir resistance, while C25F conferred a 5.4-fold increase in letermovir resistance (50% effective concentration [EC50]) by itself and a 46-fold increase in combination with V231L. The evolution of resistance mutations sooner in UL56 than in UL54 or UL97 is consistent with priorin vitroobservations, and UL56 codon 25 is a genetic locus for letermovir resistance distinct from loci previously described.

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